CN101431333B - Multi-band electronic device and multi-band signal processing method - Google Patents

Abstract

A multi-band electronic device and a multi-band signal processing method are provided. The multi-band electronic device includes first, second and third circuit portions. According to a switching signal, the first and third circuits are selectively formed into a first phase-locked loop frequency synthesizer, and the second and third circuits are not formed into a phase-locked loop at the same time. The first PLL frequency synthesizer output range is within a first frequency band. Or, according to the switch signal, selectively make the second and third circuits form a second PLL frequency synthesizer, and make the first PLL frequency synthesizer form an open circuit at the same time. The second PLL frequency synthesizer output range is within a second frequency band. The first and second frequency bands do not completely overlap.

Description

Multi-band electronic device and multi-band signal processing method

technical field

The present invention relates to a phase-locked loop frequency synthesizer, in particular to a multi-band phase-locked loop frequency synthesizer capable of synthesizing desired frequencies in multiple frequency bands.

Background technique

A phase locked loop is an electronic control system that generates a signal that locks the phase of a reference signal. FIG. 1 is a block diagram of a known PLL 100 . The phase locked loop 100 includes a phase detector 110 , a loop filter 120 , and a voltage controlled oscillator 130 . The phase detector 110 is generally a mixer, which compares the difference in frequency and phase between the reference signal Sref and the output signal Svco of the voltage-controlled oscillator 130 , and outputs a difference signal to the loop filter 120 . The loop filter 120 drives the voltage-controlled oscillator 130 according to the difference signal, so as to maintain the phase difference between the output signal Svco of the voltage-controlled oscillator 130 and the reference signal Sref at a certain value. That is, the output signal Svco is locked to the reference signal Sref, and the frequency of the two signals is the same.

Phase-locked loops are widely used in the field of electronic communication, and can be used for frequency synthesis, carrier or clock recovery, frequency modulation/demodulation, etc. FIG. 2 is a conventional PLL frequency synthesizer 200 . The PLL frequency synthesizer 200 includes a phase detector 210 , a loop filter 220 , a voltage controlled oscillator 230 , and a frequency divider 240 . The main difference between the PLL frequency synthesizer 200 and the PLL 100 is that the output signal Svco of the VCO 230 is sent to the frequency divider 240 instead of being sent to the phase detector 210 directly. The frequency divider 240 divides the output signal Svco of the voltage-controlled oscillator 230 by N times, and then outputs a frequency-divided signal Sdiv to the phase detector 210 for comparison with a reference signal. When the frequency-divided signal Sdiv is locked to the reference signal Sref, the frequency of the two signals is the same, and the output signal Svco is N times the frequency of the reference signal Sref. Accordingly, we can change the frequency division ratio (N) of the frequency divider 240 to generate output signals Svco with various stable frequencies.

With the advancement of technology, more and more electronic communication devices support two or more communication specifications at the same time, such as handheld devices that support IEEE 802.11b/g and 802.11a at the same time, or Cellular Band (900MHz) and PCS at the same time Band (1900MHz) mobile phone. Usually, when the frequency bands used by various communication standards are very different, this makes it impossible for a single voltage-controlled oscillator output frequency band of a phase-locked loop frequency synthesizer in an electronic communication device to simultaneously cover various frequency bands. Therefore, an electronic communication device supporting multiple communication standards must be provided with a plurality of PLL frequency synthesizers operating in different frequency bands to meet the requirements of different communication standards operating in different frequency bands. As a result, the complexity and cost of the system are bound to increase.

If some components of the PLL frequency synthesizer can be shared and combined with multiple PLL frequency synthesizers, the complexity and cost of the electronic communication equipment system supporting multiple communication standards at the same time can be greatly reduced. Therefore, sharing and switching specific components of multiple PLL frequency synthesizers in an electronic communication device supporting multiple communication standards is an effective method to reduce system complexity and cost while maintaining required characteristic specifications.

Contents of the invention

One aspect of the present invention is a multi-band electronic device including first, second and third circuit parts. The first circuit portion includes a first voltage controlled oscillator, a first set of switches. The first voltage-controlled oscillator outputs a first output signal within a first frequency band according to a control voltage. The first set of switches is coupled to the first voltage-controlled oscillator, and selectively enables the first voltage-controlled oscillator to output the first output signal according to a switch control signal. The second circuit part includes a second voltage controlled oscillator, a second frequency divider, and a second set of switches. The second voltage-controlled oscillator outputs a second output signal within a second frequency band according to the control voltage, wherein the first frequency band and the second frequency band do not completely overlap. The second frequency divider, coupled to the second voltage-controlled oscillator, divides the second output signal to output a second frequency-divided signal within the first frequency band or close to the first frequency band. The second group of switches is coupled to the second voltage-controlled oscillator and the second frequency divider, selectively makes the second frequency divider output the second frequency division signal according to the switch control signal, and makes the The second voltage-controlled oscillator outputs the second output signal. The third circuit part includes a first frequency divider, a phase detector, and a loop filter. The first frequency divider divides the first output signal or the second frequency-divided signal, and outputs a first frequency-divided signal. The phase detector is coupled to the first frequency divider, receives the first frequency-divided signal and a reference signal, detects a phase difference between the first frequency-divided signal and the reference signal, and outputs a phase difference signal. A loop filter, coupled to the phase detector, outputs the control voltage according to the phase difference signal, uses the control voltage to drive the first or second voltage-controlled oscillator to maintain the first frequency-divided signal and the reference signal specific phase difference. The second frequency divider divides the frequency of the second output signal to a place overlapping or close to the frequency band of the first output signal, so as to simplify the design requirements of the third circuit part. The third circuit part in the multi-band electronic device is a shared part, which can share most of the phase-locked loop circuits of the first frequency band and the second frequency band frequency synthesizers, so as to greatly reduce the complexity and cost of the system.

Another aspect of the present invention is a multi-band electronic device comprising first, second and third circuit parts. The first circuit portion includes a first voltage controlled oscillator, a first set of switches. The first voltage-controlled oscillator outputs a first output signal within a first frequency band according to a control voltage. The first set of switches is coupled to the first voltage-controlled oscillator, and selectively enables the first voltage-controlled oscillator to output the first output signal according to a switch control signal. The second circuit part includes a second voltage controlled oscillator, a second frequency divider, and a second set of switches. The second voltage-controlled oscillator outputs a second output signal within a second frequency band according to the control voltage, wherein the first frequency band and the second frequency band do not completely overlap. The second frequency divider, coupled to the second voltage-controlled oscillator, divides the second output signal to output a second frequency-divided signal within the first frequency band or close to the first frequency band. The second group of switches is coupled to the second voltage-controlled oscillator and the second frequency divider, selectively makes the second frequency divider output the second frequency division signal according to the switch control signal, and makes the The second voltage-controlled oscillator outputs the second output signal. The third circuit part includes a first frequency divider, a phase detector, a loop filter, and an adder. The first frequency divider divides the first output signal or the second frequency-divided signal, and outputs a first frequency-divided signal. The phase detector is coupled to the first frequency divider, receives the first frequency-divided signal and a reference signal, detects a phase difference between the first frequency-divided signal and the reference signal, and outputs a phase difference signal. The loop filter is coupled to the phase detector, and outputs a filtered signal according to the phase difference signal. The adder is coupled to the loop filter, adds the filtered signal to an input signal output by a baseband processor to generate the control voltage, and uses the control voltage to drive the first or second voltage-controlled oscillator to maintain the first A specific phase difference between the frequency-divided signal and the reference signal. The third circuit part in the multi-band electronic device is a shared part, which can share most of the phase-locked loop circuits of the two frequency synthesizers of the first frequency band and the second frequency band, so as to greatly reduce the complexity and cost of the system; here The adder can be used with the output of the baseband processor to adjust the output of the control voltage.

Another aspect of the present invention is a multi-band signal processing method, comprising the following steps: selectively outputting a first output signal in a first frequency band according to a switch control signal, wherein the first output signal is the first output by the voltage-controlled oscillator according to a control voltage; or selectively output a second frequency-divided signal according to the switch control signal, and make the second voltage-controlled oscillator output a second output signal in a second frequency band; wherein the The frequency of the second frequency division signal is divided from the second output signal, the second output signal is output by the second voltage-controlled oscillator according to the control voltage, the first frequency band and the second frequency band do not completely overlap; according to the switch The control signal selectively divides the frequency of the first output signal or the second frequency division signal, and outputs a first frequency division signal; detects the phase difference between the first frequency division signal and a reference signal, and outputs a phase difference outputting the control voltage according to the phase difference signal; and driving the first or second voltage-controlled oscillator with the control voltage according to the switch control signal to maintain a specific phase difference between the first frequency-divided signal and the reference signal.

Another aspect of the present invention is a multi-band signal processing method, comprising the following steps: selectively outputting a first output signal in a first frequency band according to a switch control signal, wherein the first output signal is the first output by the voltage-controlled oscillator according to a control voltage; or selectively output a second frequency-divided signal according to the switch control signal, and make the second voltage-controlled oscillator output a second output signal in a second frequency band; wherein the The frequency of the second frequency division signal is divided from the second output signal, the second output signal is output by the second voltage-controlled oscillator according to the control voltage, the first frequency band and the second frequency band do not completely overlap; according to the switch The control signal selectively divides the frequency of the first output signal or the second frequency division signal, and outputs a first frequency division signal; detects the phase difference between the first frequency division signal and a reference signal, and outputs a phase difference signal; generate a filter signal according to the phase difference signal; add the filter signal to an input signal of a baseband processor to generate the control voltage; and use the control voltage to drive the first or second voltage according to the switch control signal The oscillator is controlled to maintain a specific phase difference between the first frequency-divided signal and the reference signal.

Description of drawings

FIG. 1 is a block diagram of a known PLL.

Fig. 2 is a known PLL frequency synthesizer.

FIG. 3 is a diagram of a multi-band electronic device according to an embodiment of the invention.

FIG. 4 is a multi-band signal processing method according to an embodiment of the present invention.

FIG. 5A is a schematic diagram of a first power controller 500 and a first voltage-controlled oscillator 312 .

FIG. 5B is an exemplary embodiment of demodulator 356 .

FIG. 5C is an exemplary embodiment of the demodulator 356 and the baseband processor 370 .

FIG. 6 is a multi-band electronic device according to another embodiment of the present invention.

FIG. 7 is a multi-band signal processing method according to an embodiment of the present invention.

FIG. 8 is an exemplary embodiment of the baseband processor 670 .

FIG. 9 is a multi-band electronic device according to another embodiment of the present invention.

Description of reference symbols

100～phase-locked loop; 110～phase detector;

120～loop filter; 130～voltage controlled oscillator;

200 ~ PLL frequency synthesizer;

210～phase detector; 220～loop filter;

230～voltage controlled oscillator; 240～frequency divider;

300～multi-band electronic devices;

310-320-330～the first, second and third circuit parts;

312～the first voltage-controlled oscillator;

314-316-318～first, third and fifth switches;

322～the second voltage-controlled oscillator; 323～the second frequency divider;

324-326-328～second, fourth and sixth switches;

332～first frequency divider; 334～phase detector;

336～loop filter; 340～power supply;

351-352～low noise amplifier;

361-362～power amplifier; 353-354-363-364～switch;

355-365～mixer; 356～demodulator;

366～modulator; 370～baseband processor;

400～multi-band signal processing method;

420-460～steps; 500～the first power controller;

502～bias circuit; 504～transistor;

510～bandpass filter; 512～frequency shift keying demodulator;

514～analog-to-digital converter; 516～first frequency modem;

520-530～second and third bandpass filters;

522-532～second and third frequency modems;

540～low-pass filter; 600～multi-band electronic device;

610-620-630～the first, second and third circuit parts;

612～the first voltage-controlled oscillator; 614-616-618～the first, third and fifth switches;

622～the second voltage-controlled oscillator; 623～the second frequency divider;

624-626-628～second, fourth and sixth switches;

632～first frequency divider; 634～phase detector;

636～loop filter; 638 adder;

640～power supply unit; 650-660～power amplifier;

670～baseband processor; 700～multi-band signal processing method;

720-770～steps; 810-820～first and second frequency modulators; 812-822～first and second bandpass filters;

830～low-pass filter; 840～second adder;

900～multi-band electronic device; 902～selection device.

Detailed ways

FIG. 3 is a multi-band electronic device 300 according to an embodiment of the invention. The multi-band electronic device 300 supports transceivers operating in multiple different frequency bands (for simplicity, two frequency bands are taken as an example; eg, 2.4-2.5 GHz, 5.0-6.0 GHz). The multi-band electronic device 300 includes first, second and third circuit parts 310, 320, 330, a power supply 340, low noise amplifiers 351, 352, power amplifiers 361, 362, switches 353, 354, 363, 364, mixing Frequency converters 355, 365, a demodulator 356, a modulator 366, and a baseband processor 370. The first circuit part 310 includes a first voltage controlled oscillator 312 , first, third and fifth switches 314 , 316 , 318 . The second circuit part 320 includes a second voltage-controlled oscillator 322 , a second frequency divider 323 , second, fourth, and sixth switches 324 , 326 , and 328 . The third circuit part 330 includes a first frequency divider 332 , a phase detector 334 , and a loop filter 336 .

As mentioned above, in order to reduce system complexity and cost, some components of the PLL frequency synthesizer are shared to combine two frequency band PLL frequency synthesizers. Here, two voltage-controlled oscillators with incompletely overlapping output frequency bands are reserved so that the required low-noise signal can be directly output from a specific voltage-controlled oscillator to the mixer in the two incompletely overlapping frequency bands, and for maximum sharing.

FIG. 4 is a multi-band signal processing method 400 according to an embodiment of the present invention, and the operation of the multi-band electronic device 300 is illustrated in conjunction with FIG. 3 . The first VCO 312 outputs a first output signal Svco1 in a first frequency band (eg, 2.4-2.5 GHz frequency band) according to a control voltage output by the loop filter 336 . The first set of switches (including the first, third and fifth switches 314 , 316 , 318 ) of the first circuit portion 310 is coupled to the first VCO 312 . The first group of switches selectively enables the first voltage-controlled oscillator 312 to output the first output signal Svco1 according to a switch control signal, as in step 420-(a).

The switch control signal can control the circuit path transmitting the control voltage and the first output signal Svco1 to be turned on or off, that is, to turn on or turn off the first and third switches 314, 316 at the same time, so that the first voltage-controlled oscillator 312 outputs Or not output the first output signal Svco1.

In order to reduce unnecessary power consumption, reduce signal interference caused by the voltage-controlled oscillator 312 to other circuits, and reduce circuit components, when the first output signal Svco1 is not needed, the power supply of the first voltage-controlled oscillator 312 can also be selected to be turned off. The supplier prevents the first voltage-controlled oscillator 312 from outputting the first output signal Svco1.

The fifth switch 318 coupled to the first power supply terminal of the first circuit part 310 can be selectively coupled to the power supply 340 according to the switch control signal to control the power of the first voltage-controlled oscillator 312 supply. Alternatively, another embodiment replacing the fifth switch 318 is to use a power controller (not shown in FIG. 3 ) directly coupled to the first voltage-controlled oscillator 312 to selectively supply A voltage controlled oscillator 312 power supply. FIG. 5A is a schematic diagram of a first power controller 500 and the first VCO 312 . The first power controller 500 may include a bias circuit 502 and a transistor 504 . The bias circuit 502 can be composed of, for example, a current mirror controlled by the switch control. The bias circuit 502 outputs a bias signal according to the switch control signal. The transistor 504 selectively supplies a certain current to the first voltage-controlled oscillator 312 according to the bias signal, or supplies no current to the first voltage-controlled oscillator 312 . The power controller can be optionally placed at the upper end, the lower end or both ends of the first voltage-controlled oscillator 312 , and a switch control signal is used to determine whether to supply power to the first voltage-controlled oscillator.

In this way, in the case that the power supply of the first voltage-controlled oscillator can be selectively supplied according to a switch control signal, the first and third switches 314, 316 can be selected to be omitted, that is, the first voltage-controlled oscillator 312 is directly coupled to the Connecting the third circuit part 330 can also achieve the purpose of selectively outputting the first output signal.

If only the power supply of the first voltage-controlled oscillator 312 is turned off without using the first and third switches 314, 316 to block the circuit path, the circuit components of the first voltage-controlled oscillator 312 may still become other circuits without power supply The load will further affect the operation of the multi-band electronic device 300 . Therefore, when the first output signal Svco1 is not needed, the first voltage-controlled oscillator 312 cannot output the first output signal Svco1 by controlling the first, third and fifth switches 314, 316 and 318, or The outputted first output signal Svco1 cannot be coupled to the phase detector 334 . For example, the first and/or third switch 314, 316 can be combined to cut off the circuit path of the first circuit portion 310, and the fifth switch 318 can be used to close the power supply to the first voltage-controlled oscillator; or the fifth switch can be used alone 318 turns off the power supply to the first voltage-controlled oscillator 312 ; or only the first switch 314 can be used to cut off the output circuit path of the first output signal Svco1 .

The second voltage-controlled oscillator 322 outputs a second output signal Svco2 in a second frequency band (eg, 5.0-6.0 GHz frequency band) according to the control voltage. The first frequency band does not completely overlap with the second frequency band. The second frequency divider 323 divides the frequency of the second output signal Svco2 (for example, twice the frequency), and outputs a second frequency division signal (in this example, the frequency range of the second frequency division signal is 2.5-3.0 GHz). In this way, the third circuit part 330 designed to process signals in the 2.4-3.0 GHz frequency band can be shared. In this way, all voltage-controlled oscillators and frequency dividers can be designed under appropriate bandwidth specifications to meet the requirements of multi-band 2.4-2.5GHz and 5.0-6.0GHz without the need for very wide-band complex circuits or two complete and independent Phase-locked loop frequency synthesizer. The second group of switches (including the second, fourth, and sixth switches 324 , 326 , 328 ) of the second circuit part 320 is coupled to the second voltage-controlled oscillator 322 and the second frequency divider 323 . The second group of switches selects the second frequency divider 323 to output the second frequency-divided signal according to the switch control signal, as in step 420-(b).

The switch control signal can control the conduction or disconnection of the circuit path that transmits the control voltage and the second frequency division signal, that is, the second and fourth switches 324, 326 are turned on or off at the same time, so as to select the second voltage-controlled oscillator 322 and the second frequency divider 323 output or not output the second output signal Svco2 and the second frequency division signal.

In order to reduce unnecessary power consumption, reduce signal interference caused by the voltage-controlled oscillator 322 to other circuits, and reduce circuit components, the second voltage-controlled oscillator 322 and the second frequency divider can also be controlled only by the switch control signal. 323 for power supply so that the second frequency divider 323 outputs or does not output the second frequency-divided signal. The sixth switch 328 coupled to the second power supply terminal of the second circuit part 320 can be selectively coupled to the power supply 340 according to the switch control signal to control the second voltage controlled oscillator 322 and the The power supply of the second frequency divider 323 . Alternatively, a second power controller (not shown in FIG. 3 ) is used to selectively supply power to the second voltage-controlled oscillator 322 and the second frequency divider 323 according to the switch control signal. The second power controller may include two sets of bias circuits and transistors to supply power to the second voltage-controlled oscillator 322 and the second frequency divider 323 respectively. The detailed operation thereof is similar to the operation of the first power controller 500 and the first voltage-controlled oscillator 312 , and will not be repeated here.

Controlling the power supply of the second voltage-controlled oscillator 322 and the second frequency divider 323 so that the second frequency divider 323 outputs or does not output the second frequency-divided signal can save the second and fourth switches 324 and 326 . That is, the second voltage-controlled oscillator 322 and the second frequency divider 323 are directly coupled to the third circuit part 330 .

If only the power supply of the second voltage-controlled oscillator 322 is turned off without using a switch to block the circuit path, the circuit components of the second voltage-controlled oscillator 322 may still become loads of other circuits without power supply, which may affect the Operation of the multi-band electronic device 300 . Therefore, when the second output signal Svco2 is not needed, by controlling the second, fourth and sixth switches 324, 326, 328, the second voltage-controlled oscillator 322 cannot output the second output signal Svco2, or The output second output signal Svco2 cannot be coupled to the phase detector 334 . For example, the second and/or fourth switch 324, 326 can be combined to cut off the circuit path of the second circuit portion 320, and the sixth switch 328 can be used to close the power supply to the second voltage-controlled oscillator 322; or the sixth switch 328 can be used alone The switch 328 turns off the power supply to the second voltage-controlled oscillator 322 ; the second switch 324 can also be used only to cut off the circuit path of the second output signal Svco2 coupled to the phase detector.

According to the switch control signal, the first frequency divider 332 can divide the first output signal Svco1 or the second frequency-divided signal to output a first frequency-divided signal, as in step 430 . The first frequency divider 332, as known by those skilled in the art, can be a counter, or can include a frequency divider with a fixed divisor and another frequency divider with a controllable divisor.

The phase detector 334 receives the first frequency-divided signal and a stable, low-noise reference signal Sref, detects a phase difference between the first frequency-divided signal and the reference signal, and outputs a phase difference signal, as in step 440 .

The loop filter 336 outputs the control voltage according to the phase difference signal, as in step 450; and uses the control voltage to drive the first or second voltage-controlled oscillator 312, 322 to maintain the first frequency-divided signal and the reference A specific phase difference of the signal (step 460). Afterwards, return to step 420 .

By utilizing the first and second sets of switches and the switch control signals, the first circuit part 310 and the third circuit part 330 can form a first PLL frequency synthesizer. The first PLL frequency synthesizer locks the reference signal Sref, and outputs a first output signal Svco1 at a first frequency band. Similarly, by utilizing the first and second sets of switches and the switch control signal, the second circuit part 320 and the third circuit part 330 can form a second PLL frequency synthesizer. The second PLL frequency synthesizer locks the reference signal Sref, and outputs a second output signal Svco2 in a second frequency band. The first and second output signals Svco1 and Svco2 can be used by the multi-band electronic device 300 , for example, for mixing, providing a clock, and so on.

Regarding the part of receiving or sending signals, the low noise amplifiers 351 and 352 respectively amplify the first and second received radio frequency signals in different frequency bands, and output the first and second radio frequency signals. The third group of switches includes the seventh and ninth switches 353 and 354. According to the switch control signal, the first radio frequency signal or the second radio frequency signal is selectively transmitted to an input end of the first mixer 355. The signal at the input end is the third radio frequency signal. The first mixer 355 is coupled to the third set of switches, the first and second voltage-controlled oscillators 312, 322, and the switch control signal and the first and second set of switches select the phase-locked frequency signal as the first output signal Svco1 or the second output signal Svco2; the phase-locked frequency signal is mixed with the third radio frequency signal to output a first mixed frequency signal. The demodulator 356 is coupled to the mixer 355 , demodulates the first mixed frequency signal, and outputs a demodulated signal to a baseband processor 370 .

The modulator 366 modulates a baseband signal output by the baseband processor 370 and outputs a modulated signal. The second mixer 365 is coupled to the modulator 366 and the first and second voltage-controlled oscillators 312 , 322 . The switch control signal and the first and second groups of switches select the phase-locked frequency signal as the first output signal Svco1 or the second output signal Svco2; the phase-locked frequency signal is mixed with the modulation signal, and a second mixed frequency radio frequency signal is output . The eighth and tenth switches 363 and 364 are switched according to the switch control signal, and the power amplifier 361 or 362 is selectively used to send the second mixed radio frequency signal. The power amplifiers 361 and 362 are respectively designed to amplify the second mixed frequency radio frequency signals located in different frequency bands, and can also be combined into one broadband power amplifier under feasible technology.

FIG. 5B is an exemplary embodiment of demodulator 356 . The demodulator 356 includes a bandpass filter 510 , a frequency shift keying (FSK, frequency shift keying) demodulator 512 , and an analog-to-digital converter 514 . The bandpass filter 510 is coupled to the first mixer 355 to filter the mixed signal and output a first bandpass filtered signal. The FSK demodulator 512 is coupled to the first bandpass filter 510, performs FSK demodulation on the bandpass filtered signal, and outputs a FSK demodulated signal. The analog-to-digital converter 514 performs analog-to-digital conversion on the FSK demodulated signal, and outputs a digital signal. The analog-to-digital converter 514 can be a data slicer (data slicer) that judges 0/1 through the voltage signal.

FIG. 5C is an exemplary embodiment of the demodulator 356 and the baseband processor 370 . The demodulator 356 includes a first bandpass filter 510 and a first frequency modem 516 . The first bandpass filter 510 is coupled to the mixer 355 to filter the mixed signal and output a first bandpass filtered signal. The first frequency modem 516 is coupled to the first bandpass filter 510 to perform frequency modulation and demodulation on the bandpass filtered signal, and outputs a first demodulated signal. The baseband processor 370 is coupled to the frequency modem 516 and includes second and third bandpass filters 520 and 530 , second and third frequency modems 522 and 532 , and a low-pass filter 540 . The second bandpass filter 520 filters the first demodulated signal, and extracts a second bandpass signal from the first demodulated signal. The second frequency modem 522 performs frequency modulation and demodulation on the second bandpass signal, and outputs a first audio signal. The third bandpass filter 530 filters the first demodulated signal, and extracts a third bandpass signal from the first demodulated signal. The third frequency modem 532 performs frequency modulation and demodulation on the third bandpass signal, and outputs a second audio signal. The low-pass filter 540 filters the first demodulated signal, and extracts a video signal from the first demodulated signal.

FIG. 6 is a multi-band electronic device (FM transmitter) 600 according to an embodiment of the present invention. The multi-band electronic device 600 supports frequency modulated transmitters operating in two different frequency bands (eg, 2.4GHz, 5.8GHz). The multi-band electronic device 600 includes first, second, and third circuit parts 610 , 620 , 630 , a power supply 640 , power amplifiers 650 , 660 , and a baseband processor 670 . The first circuit part 610 includes a first voltage controlled oscillator 612 , first, third and fifth switches 614 , 616 , 618 . The second circuit part 620 includes a second voltage-controlled oscillator 622 , a second frequency divider 623 , second, fourth, and sixth switches 624 , 626 , and 628 . The third circuit 630 includes a first frequency divider 632 , a phase detector 634 , a loop filter 636 , and a first adder 638 .

As mentioned above, in order to reduce system complexity and cost, some components of the frequency modulation transmitter are shared to combine two frequency band modulation transmitters. Here, two voltage-controlled oscillators with incompletely overlapping output frequency bands are reserved so that low-noise frequency modulation signals can be output in the two incompletely overlapping frequency bands, and the maximum degree of sharing can be achieved.

FIG. 7 is a multi-band signal processing method 700 according to an embodiment of the present invention, and the operation of the multi-band electronic device 600 is described in conjunction with FIG. 6 . The first VCO 612 outputs a first output signal Svco1 in a first frequency band (eg, a frequency band centered at 2.4 GHz) according to a control voltage. The first group of switches (including the first, third and fifth switches 614 , 616 , 618 ) of the first circuit portion 610 is coupled to the first VCO 612 . The first group of switches selectively enables the first voltage-controlled oscillator 612 to output the first output signal Svco1 according to a switch control signal, as in step 720-(a).

The switch control signal can control the circuit path transmitting the control voltage and the first output signal Svco1 to be turned on or off, that is, to turn on or turn off the first and third switches 614 and 616 at the same time, so that the first voltage-controlled oscillator 612 outputs Or not output the first output signal Svco1.

In order to reduce unnecessary power consumption, reduce signal interference caused by the voltage-controlled oscillator 612 to other circuits, and reduce circuit components, it is also possible to control the power supply of the first voltage-controlled oscillator 612 only by using the switch control signal so that the first voltage-controlled oscillator 612 A VCO 612 outputs or does not output the first output signal Svco1.

The fifth switch 618, which can be coupled to the first power supply terminal of the first circuit part 610, is selectively coupled to the power supply 640 according to the switch control signal to control the power supply of the first voltage-controlled oscillator 612 . Alternatively, a power controller (not shown in FIG. 6 ) coupled to the first VCO 612 is used to selectively supply power to the first VCO 612 according to the switch control signal. The detailed operation thereof is similar to the operation of the first power controller 500 and the first voltage-controlled oscillator 312 , and will not be repeated here.

In this way, the first and third switches 614 and 616 can be omitted. That is, the first VCO 612 is directly coupled to the third circuit part 630 .

If only the power supply of the first voltage-controlled oscillator 612 is turned off without using the first and third switches 614, 616 to block the circuit path, the circuit components of the first voltage-controlled oscillator 612 may still become other circuits without power supply The load will further affect the operation of the multi-band electronic device 600 . Therefore, when the first output signal is not needed, the first and third switches 614, 616 can be combined to simultaneously turn off the power supply and cut off the circuit path. Or just combine the first switch 614 to turn off the power supply and cut off the circuit path.

The second voltage-controlled oscillator 622 outputs a second output signal Svco2 in a second frequency band (eg, a frequency band centered at 5.8 GHz) according to the control voltage. The first frequency band does not completely overlap with the second frequency band. The second frequency divider 623 divides the frequency of the second output signal Svco2 (in this example, divides the frequency by two), and outputs a second frequency-divided signal within the first frequency band or close to the first frequency band. In this way, the third circuit part 630 designed to process signals in the vicinity of the first frequency band range can be shared. The second group of switches (including the second, fourth, and sixth switches 624 , 626 , 628 ) of the second circuit portion 620 is coupled to the second voltage-controlled oscillator 622 and the second frequency divider 623 . The second group of switches selectively enables the second frequency divider 623 to output the second frequency-divided signal according to the switch control signal, as in step 720-(b).

The switch control signal can control the circuit path that transmits the control voltage and the second frequency division signal to be turned on or off, that is, to turn on or turn off the second and fourth switches 624, 626 at the same time, so that the second voltage-controlled oscillator 622 outputs Or the second output signal Svco2 is not output.

In order to reduce unnecessary power consumption, reduce signal interference caused by the voltage-controlled oscillator 622 to other circuits, and reduce circuit components, the second voltage-controlled oscillator 622 and the second frequency divider can also be controlled only by the switch control signal. 623 is supplied with power so that the second frequency divider 623 outputs or does not output the second frequency-divided signal.

The sixth switch 628, which can be coupled to the second power supply terminal of the second circuit part 620, is selectively coupled to the power supply 640 according to the switch control signal to control the second voltage-controlled oscillator 622 and the second voltage-controlled oscillator 622. Power supply for frequency divider 623. Alternatively, a second power controller (not shown in FIG. 6 ) is used to selectively supply power to the second voltage-controlled oscillator 622 and the second frequency divider 623 according to the switch control signal. The second power controller may include two sets of bias circuits and transistors to supply power to the second voltage-controlled oscillator 622 and the second frequency divider 623 respectively. The detailed operation thereof is similar to the operation of the first power controller 500 and the first voltage-controlled oscillator 312 , and will not be repeated here.

In this way, the second and fourth switches 624 and 626 can be omitted. That is, the second voltage-controlled oscillator 622 and the second frequency divider 623 are directly coupled to the third circuit part 630 .

If only the power supply of the second voltage-controlled oscillator 622 is turned off without using a switch to block the circuit path, the circuit components of the second voltage-controlled oscillator 622 may still become loads of other circuits without power supply, thereby affecting the multiple circuits. Operation of Band Electronics 600 . Therefore, when the second output signal is not needed, the second and fourth switches 624, 626 can be combined to simultaneously turn off the power supply and cut off the circuit path. Or just combine the second switch 624 to simultaneously turn off the power supply and cut off the circuit path.

The first frequency divider 632 divides the first output signal Svco1 or the second frequency-divided signal to output a first frequency-divided signal, as in step 730 . The first frequency divider 632, as known by those skilled in the art, can be a counter, or can include a frequency divider with a fixed divisor and another frequency divider with a controllable divisor.

The phase detector 634 receives the first frequency-divided signal and a stable, low-noise reference signal Sref, detects a phase difference between the first frequency-divided signal and the reference signal, and outputs a phase difference signal, as in step 740 .

The loop filter 636 is coupled to the phase detector 634 to generate a filter signal according to the phase difference signal, as in step 750 .

The first adder 638 is coupled to the loop filter 636, adds the filtered signal to an input signal Si output by the baseband processor 670 to generate the control voltage (as in step 760), and uses the control voltage to drive the first One or the second VCO 612 , 622 to maintain a specific phase difference between the first frequency-divided signal and the reference signal, as in step 770 . Afterwards, return to step 720 .

By using the first and second sets of switches and the switch control signal, the first circuit part 610 and the third circuit part 630 can selectively form a frequency modulator. The frequency modulator performs frequency modulation on the input signal Si, and outputs a first output signal Svco1 in a first frequency band. The first output signal Svco1 is a frequency modulation signal in the first frequency band. Similarly, by using the first and second sets of switches and the switch control signal, the second circuit part 620 and the third circuit part 630 can selectively form another frequency modulator. The further frequency modulator frequency-modulates the input signal Si and outputs a second output signal Svco2 in a second frequency band. The second output signal is a frequency modulation signal in the second frequency band. In this way, the multi-band electronic device 600 can use another frequency band for communication when the channel transmission condition of one frequency band is not good. The power amplifiers 650 and 660 can respectively amplify the frequency modulation signals in the first and second frequency bands and output the first and second amplified signals respectively. Next, the antenna is used to transmit the first and second amplified signals.

FIG. 8 is an exemplary embodiment of the baseband processor 670 . The baseband processor 670 includes first and second frequency modulators 810 and 820 , first and second bandpass filters 812 and 822 , a lowpass filter 830 and a second adder 840 . The first frequency modulator 810 modulates a first audio signal and outputs a first frequency modulated signal. The first band-pass filter 812 filters the first frequency modulation signal, and outputs a first band-pass signal. The second frequency modulator 820 modulates a second audio signal and outputs a second frequency modulated signal. The second band-pass filter 822 filters the second frequency modulation signal to output a second band-pass signal. The low-pass filter 830 filters a video signal and outputs a video filtered signal. The second adder 840 adds the first and second bandpass signals and the video filter signal to generate the input signal Si.

FIG. 9 shows a multi-band electronic device 900 according to another embodiment of the present invention. For the sake of brevity, the same components in FIG. 9 and FIG. 3 use the same numbers or symbols.

The multi-band electronic device 900 includes: a phase detector 334, which receives a reference signal Sref and a frequency signal Sf, detects the phase difference between the frequency signal Sf and the reference signal Sref and outputs a phase difference signal; and, a loop filter A device 336, coupled to the phase detector 334, outputs a control voltage according to the phase difference signal. The phase detector 334 and the loop filter 336 constitute a shared circuit part (or called a third circuit part) 330 .

The multi-band electronic device 900 further includes: a first voltage-controlled oscillator 312 coupled to the loop filter 336, and outputs a first output signal Svco1 in a first frequency band when receiving the control voltage signal; and , a first frequency divider 332 , coupled to the first voltage-controlled oscillator 312 , when receiving the first output signal Svco1 , divides the first output signal Svco1 to output a first frequency-divided signal. The first VCO 312 and the first frequency divider 332 form a first circuit part 310 .

The multi-band electronic device 900 further includes: a second voltage-controlled oscillator 322 coupled to the loop filter 336, and outputs a second output signal Svco2 in a second frequency band when receiving the control voltage signal; and , a second frequency divider 323 , coupled to the second voltage-controlled oscillator 322 , when receiving the second output signal Svco2 , divides the second output signal Svco2 to output a second frequency-divided signal. The second voltage-controlled oscillator 322 and the first frequency divider 323 form a second circuit part.

The multi-band electronic device 900 also includes a selection device 902, which is coupled to the first and second frequency division signals, and determines to output the first or second frequency signal according to the control of a switch control signal (not shown in FIG. 9 ). A frequency-divided signal by two is used as the frequency signal Sf. The selection device 902 can be a two-to-one multiplexer; or it can be composed of two switches 314 and 324 (as shown in FIG. 9 ). Wherein, the switches 314 and 324 are controlled by the switch control signal. When the switch 314 is turned on (or turned off), the switch 324 is turned off (or turned on), so as to select and output the first or second frequency division signal as the frequency Signal Sf.

The first circuit part 310 also includes a switch 316, which can be selectively arranged between the loop filter 336 and the first voltage-controlled oscillator 312, or between the first voltage-controlled oscillator 312 and the first frequency division device 332. The second circuit part 320 also includes a switch 326, which can be selectively arranged between the loop filter 336 and the second voltage-controlled oscillator 322, or between the second voltage-controlled oscillator 322 and the second frequency division device 323. In this embodiment, the switch 316 is disposed between the loop filter 336 and the first VCO 312 , and the switch 326 is disposed between the loop filter 336 and the second VCO 322 .

Whether the switches 316 and 326 are turned on is controlled by the switch control signal. And the conduction (or disconnection) states of the switch 316 and the switch 326 are opposite to each other; and when the switch 314 is on, the switch 316 is also on; conversely, when the switch 324 is on, the switch 326 is also on.

In order to achieve the purpose of saving power, a switch 318 can also be set to be coupled between the first voltage-controlled oscillator 312 and its power supply (that is, the power supply 340). The switch 318 is controlled by the switch control signal. When the switch 324 is turned on When the second frequency-divided signal is output, the switch 318 is not turned on, so as to cut off the power of the first voltage-controlled oscillator 312 to save power. Similarly, a switch 328 can also be set to be coupled between the second voltage-controlled oscillator 312 and its power supply (that is, the power supply 340), the switch 328 is controlled by the switch control signal, and when the switch 314 is turned on, the output When the first frequency division signal is used, the switch 328 is not turned on to cut off the power of the second voltage-controlled oscillator 322 to save power.

It can be seen from FIG. 3 or FIG. 9 that the first circuit part 310 and the second circuit part 320 can share the third circuit part 330 by controlling the switches 314-318 and 324-328, so as to support different communication standards (or frequency bands) ) signal Svco1 or Svco2. Of course, the present invention does not only support two specifications or frequency bands, as long as an additional frequency band with output frequency bands is added between the loop filter 336 and the phase detector 334 (or the first frequency divider 332 ). Other circuit parts of the voltage-controlled oscillator, together with the corresponding switch control, can expand the communication frequency band or specification that can be supported. In the same way, as can be seen from FIG. 6, as long as other circuit parts with voltage-controlled oscillators outputting different frequency bands are added between the loop filter 636 (or adder 638) and the first frequency divider 632 , and cooperate with the corresponding switch control, that is, the supported communication frequency band or specification can be expanded.

A pioneering technique of the present invention is to combine multiple PLL frequency synthesizers by using switches and switch control signals to share some components of the PLL frequency synthesizer. In this way, the system complexity and cost of electronic communication equipment supporting two or more communication standards can be greatly reduced.

Although the invention is illustrated and described herein in terms of one or more specific examples, the invention should not be limited to the details shown, but may be modified without departing from the spirit of the invention and in the claims. Many different modifications and structural changes are realized within the same field and scope. Accordingly, it is best that the appended claims be construed broadly and in a manner consistent with the field of the invention, making this statement prior to asserting the invention.

Claims (39)

1. A multi-band electronic device comprising: A first circuit portion comprising: A first voltage-controlled oscillator, outputting a first output signal within a first frequency band according to a control voltage; a second circuit portion comprising: a second voltage controlled oscillator outputting a second output signal in a second frequency band according to the control voltage, wherein the first frequency band and the second frequency band do not completely overlap; and A second frequency divider, coupled to the second voltage-controlled oscillator, divides the second output signal to output a second frequency-divided signal; - a third circuit part, comprising: A first frequency divider divides the first output signal or the second frequency-divided signal, and outputs a first frequency-divided signal; A phase detector, coupled to the first frequency divider, receives the first frequency-divided signal and a reference signal, detects a phase difference between the first frequency-divided signal and the reference signal, and outputs a phase difference signal ;as well as a loop filter, coupled to the phase detector, outputting the control voltage according to the phase difference signal; and a switch control signal, selectively causing the first voltage-controlled oscillator to output the first output signal to the first frequency divider, and causing the loop filter to output the control voltage to the first voltage-controlled oscillator; Or the switch control signal causes the second voltage-controlled oscillator to output a second output signal, the second frequency divider outputs the second frequency-divided signal to the first frequency divider, and enables the control output of the loop filter to voltage to the second VCO. 2. A multi-band electronic device comprising: A first circuit portion comprising: a first voltage-controlled oscillator outputting a first output signal within a first frequency band according to a control voltage; and A first group of switches, coupled to the first voltage-controlled oscillator, selectively make the first voltage-controlled oscillator output the first output signal according to a switch control signal; a second circuit portion comprising: a second voltage-controlled oscillator outputting a second output signal in a second frequency band according to the control voltage, wherein the first frequency band and the second frequency band do not completely overlap; A second frequency divider, coupled to the second voltage-controlled oscillator, divides the second output signal to output a second frequency-divided signal; and A second group of switches, coupled to the second voltage-controlled oscillator and the second frequency divider, selectively make the second voltage-controlled oscillator output a second output signal according to the switch control signal and make the second The frequency divider outputs the second frequency division signal; - a third circuit part, comprising: A first frequency divider divides the first output signal or the second frequency-divided signal, and outputs a first frequency-divided signal; A phase detector, coupled to the first frequency divider, receives the first frequency-divided signal and a reference signal, detects a phase difference between the first frequency-divided signal and the reference signal, and outputs a phase difference signal ;as well as A loop filter, coupled to the phase detector, outputs the control voltage according to the phase difference signal. 3. The multi-band electronic device as claimed in claim 2, wherein The first set of switches, also contains: a first switch, coupled to the first voltage-controlled oscillator, selectively coupled to the first frequency divider according to the switch control signal; and a third switch, coupled to the first voltage controlled oscillator, selectively coupled to the loop filter according to the switch control signal; and The second set of switches, also contains: a second switch, coupled to the second frequency divider, selectively coupled to the first frequency divider according to the switch control signal; and A fourth switch, coupled to the second voltage-controlled oscillator, is selectively coupled to the loop filter according to the switch control signal. 4. The multi-band electronic device as claimed in claim 3, wherein The first set of switches, also contains: a fifth switch, coupled to a first power supply terminal of the first circuit part, and selectively coupled to a power supply according to the switch control signal; and The second set of switches, also contains: A sixth switch, coupled to a second power supply terminal of the second circuit part, and selectively coupled to the power supply according to the switch control signal. 5. The multi-band electronic device as claimed in claim 3, wherein The first circuit portion also includes: A first power controller, coupled to the first voltage-controlled oscillator, selectively supplies power to the first voltage-controlled oscillator according to the switch control signal; The second circuit portion also includes: A second power controller, coupled to the second voltage-controlled oscillator and the second frequency divider, selectively supplies power to the second voltage-controlled oscillator and the second frequency divider according to the switch control signal . 6. The multi-band electronic device as claimed in claim 2, wherein The first set of switches, also contains: a fifth switch, coupled to a first power supply terminal of the first circuit part, and selectively coupled to a power supply according to the switch control signal; and The second set of switches, also contains: A sixth switch, coupled to a second power supply terminal of the second circuit part, and selectively coupled to the power supply according to the switch control signal. 7. The multi-band electronic device as claimed in claim 6, wherein The first set of switches, also contains: a first switch, coupled to the first voltage-controlled oscillator, selectively coupled to the first frequency divider according to the switch control signal; and a third switch, coupled to the first voltage controlled oscillator, selectively coupled to the loop filter according to the switch control signal; and The second set of switches, also contains: A fourth switch, coupled to the second voltage-controlled oscillator, is selectively coupled to the loop filter according to the switch control signal. 8. The multi-band electronic device as claimed in claim 2, wherein The first circuit portion also includes: A first power controller, coupled to the first voltage-controlled oscillator, selectively supplies power to the first voltage-controlled oscillator according to the switch control signal; The second circuit portion also includes: A second power controller, coupled to the second voltage-controlled oscillator and the second frequency divider, selectively supplies power to the second voltage-controlled oscillator and the second frequency divider according to the switch control signal . 9. The multi-band electronic device as claimed in claim 8, wherein The first set of switches, also contains: a first switch, coupled to the first voltage-controlled oscillator, selectively coupled to the first frequency divider according to the switch control signal; and a third switch, coupled to the first voltage controlled oscillator, selectively coupled to the loop filter according to the switch control signal; and The second set of switches, also contains: A fourth switch, coupled to the second voltage-controlled oscillator, is selectively coupled to the loop filter according to the switch control signal. 10. The multi-band electronic device as claimed in claim 1, further comprising: A third group of switches, selectively receiving a first radio frequency signal or a second radio frequency signal according to the switch control signal, and outputting a third radio frequency signal; A mixer, coupled to the third set of switches, the first and second voltage-controlled oscillators, mixes the first or second output signal with the third radio frequency signal, and outputs a mixed frequency signal; and A demodulator, coupled to the mixer, demodulates the mixed frequency signal. 11. The multi-band electronic device as claimed in claim 10, wherein the demodulator further comprises: A first band-pass filter, coupled to the mixer, filters the mixed signal, and outputs a first band-pass filtered signal; A first frequency modem, coupled to the first bandpass filter, performs frequency modulation and demodulation on the first bandpass filtered signal, and outputs a first demodulated signal; A baseband processor, coupled to the first frequency modem, comprising: A second band-pass filter for filtering the first demodulated signal and outputting a second band-pass signal; A second frequency modem, which performs frequency modulation and demodulation on the second bandpass signal, and outputs a first audio signal; A third band-pass filter for filtering the first demodulated signal and outputting a third band-pass signal; A third frequency modem, which performs frequency modulation and demodulation on the third bandpass signal, and outputs a second audio signal; and A low-pass filter filters the first demodulated signal to output a video signal. 12. The multi-band electronic device as claimed in claim 10, wherein the demodulator further comprises: A band-pass filter, coupled to the mixer, filters the mixed frequency signal, and outputs a first band-pass filtered signal; A frequency shift keying demodulator, coupled to the bandpass filter, performs frequency shift keying demodulation on the first bandpass filtered signal, and outputs a demodulated signal; An analog-to-digital converter performs analog-to-digital conversion on the demodulated signal and outputs a digital signal. 13. The multi-band electronic device as claimed in claim 1, further comprising: a modulator outputting a modulated signal; and A mixer, coupled to the modulator, the first and second voltage-controlled oscillators, mixes the first or second output signal with the modulated signal, and outputs a mixed frequency signal. 14. The multi-band electronic device of claim 1, further comprising: A third group of switches, selectively receiving a first radio frequency signal or a second radio frequency signal according to the switch control signal, and outputting a third radio frequency signal; A first mixer, coupled to the third set of switches, the first and second voltage-controlled oscillators, mixes the first or second output signal with the third radio frequency signal, and outputs a first mixed frequency signal; A demodulator, coupled to the first mixer, demodulates the first mixed frequency signal; a modulator outputting a modulated signal; and A second mixer, coupled to the modulator, the first and second voltage-controlled oscillators, mixes the first or second output signal with the modulated signal, and outputs a second mixed frequency signal. 15. The multi-band electronic device as claimed in claim 14, wherein the demodulator further comprises: A first bandpass filter, coupled to the first mixer, filters the first mixed frequency signal, and outputs a first filtered signal; and An analog-to-digital converter, coupled to the first bandpass filter, performs analog-to-digital conversion on the first filtered signal, and outputs a first digital signal; The modulator also contains: A digital-to-analog converter that receives a second digital signal, performs digital-to-analog conversion on the second digital signal, and outputs an analog signal; and a second bandpass filter, coupled to the digital-to-analog converter and the second mixer, to filter the analog signal; It also includes a baseband processor coupled to the analog-to-digital converter and the digital-to-analog converter to output the second digital signal and process the input first digital signal. 16. A multi-band electronic device comprising: A first circuit portion comprising: A first voltage-controlled oscillator, outputting a first output signal within a first frequency band according to a control voltage; a second circuit portion comprising: a second voltage-controlled oscillator outputting a second output signal in a second frequency band according to the control voltage, wherein the first frequency band and the second frequency band do not completely overlap; A second frequency divider, coupled to the second voltage-controlled oscillator, divides the second output signal to output a second frequency-divided signal; - a third circuit part, comprising: A first frequency divider divides the first output signal or the second frequency-divided signal, and outputs a first frequency-divided signal; A phase detector, coupled to the first frequency divider, receives the first frequency-divided signal and a reference signal, detects a phase difference between the first frequency-divided signal and the reference signal, and outputs a phase difference signal ; A loop filter, coupled to the phase detector, outputs a filtered signal according to the phase difference signal; A first adder, coupled to the loop filter, adds the filtered signal to an input signal to generate the control voltage; and a switch control signal selectively causes the first VCO to output the first output signal to the first frequency divider, and causes the first adder to output the control voltage to the first VCO, or The switch control signal makes the second voltage-controlled oscillator output a second output signal, the second frequency divider outputs the second frequency-divided signal to the first frequency divider, and makes the control of the output of the first adder voltage to the second VCO. 17. A multi-band electronic device comprising: A first circuit portion comprising: a first voltage-controlled oscillator outputting a first output signal within a first frequency band according to a control voltage; and A first group of switches, coupled to the first voltage-controlled oscillator, selectively make the first voltage-controlled oscillator output the first output signal according to a switch control signal; a second circuit portion comprising: a second voltage-controlled oscillator outputting a second output signal in a second frequency band according to the control voltage, wherein the first frequency band and the second frequency band do not completely overlap; A second frequency divider, coupled to the second voltage-controlled oscillator, divides the second output signal to output a second frequency-divided signal; and A second group of switches, coupled to the second voltage-controlled oscillator and the second frequency divider, selectively make the second voltage-controlled oscillator output a second output signal according to the switch control signal and make the second The frequency divider outputs the second frequency division signal; - The third circuit part: A first frequency divider divides the frequency of the first output signal or the second frequency-divided signal, and outputs a first frequency-divided signal; A phase detector, coupled to the first frequency divider, receives the first frequency-divided signal and a reference signal, detects a phase difference between the first frequency-divided signal and the reference signal, and outputs a phase difference signal ; A loop filter, coupled to the phase detector, outputs a filtered signal according to the phase difference signal; and A first adder, coupled to the loop filter, adds the filtered signal to an input signal to generate the control voltage. 18. The multi-band electronic device as claimed in claim 17, wherein The first set of switches, also contains: a first switch, coupled to the first voltage-controlled oscillator, selectively coupled to the first frequency divider according to the switch control signal; and a third switch, coupled to the first voltage-controlled oscillator, selectively coupled to the first adder according to the switch control signal; and The second set of switches, also contains: a second switch, coupled to the second frequency divider, selectively coupled to the first frequency divider according to the switch control signal; and A fourth switch, coupled to the second voltage-controlled oscillator, is selectively coupled to the first adder according to the switch control signal. 19. The multi-band electronic device as claimed in claim 18, wherein The first set of switches, also contains: a fifth switch, coupled to a first power supply terminal of the first circuit part, and selectively coupled to a power supply according to the switch control signal; and The second set of switches, also contains: A sixth switch, coupled to a second power supply terminal of the second circuit part, and selectively coupled to the power supply according to the switch control signal. 20. The multi-band electronic device as claimed in claim 18, wherein the first circuit part further comprises: A first power controller, coupled to the first voltage-controlled oscillator, selectively supplies power to the first voltage-controlled oscillator according to the switch control signal; The second circuit portion also includes: A second power controller, coupled to the second voltage-controlled oscillator and the second frequency divider, selectively supplies power to the second voltage-controlled oscillator and the second frequency divider according to the switch control signal . 21. The multi-band electronic device as claimed in claim 17, wherein The first set of switches, also contains: a fifth switch, coupled to a first power supply terminal of the first circuit part, and selectively coupled to a power supply according to the switch control signal; and The second set of switches, also contains: A sixth switch, coupled to a second power supply terminal of the second circuit part, and selectively coupled to the power supply according to the switch control signal. 22. The multi-band electronic device as claimed in claim 21, wherein The first set of switches, also contains: a first switch, coupled to the first voltage-controlled oscillator, selectively coupled to the first frequency divider according to the switch control signal; and a third switch, coupled to the first voltage-controlled oscillator, selectively coupled to the first adder according to the switch control signal; and The second set of switches, also contains: A fourth switch, coupled to the second voltage-controlled oscillator, is selectively coupled to the first adder according to the switch control signal. 23. The multi-band electronic device as claimed in claim 17, wherein The first circuit portion also includes: A first power controller, coupled to the first voltage-controlled oscillator, selectively supplies power to the first voltage-controlled oscillator according to the switch control signal; The second circuit portion also includes: A second power controller, coupled to the second voltage-controlled oscillator and the second frequency divider, selectively supplies power to the second voltage-controlled oscillator and the second frequency divider according to the switch control signal . 24. The multi-band electronic device as claimed in claim 23, wherein The first set of switches, also contains: a first switch, coupled to the first voltage-controlled oscillator, selectively coupled to the first frequency divider according to the switch control signal; and a third switch, coupled to the first voltage controlled oscillator, selectively coupled to the loop filter according to the switch control signal; and The second set of switches, also contains: A fourth switch, coupled to the second voltage-controlled oscillator, is selectively coupled to the loop filter according to the switch control signal. 25. The multi-band electronic device of claim 17, further comprising: A baseband processor, coupled to the first adder, outputs the input signal, including: A first frequency modulator, which modulates a first audio signal and outputs a first frequency modulation signal; A first band-pass filter for filtering the first frequency modulation signal and outputting a first band-pass signal; A second frequency modulator, which modulates a second audio signal and outputs a second frequency modulation signal; A second band-pass filter for filtering the second frequency modulation signal and outputting a second band-pass signal; A low-pass filter is used to filter a video signal and output a video filtered signal; A second adder adds the first and second bandpass signals and the video filter signal to generate the input signal. 26. A multi-band signal processing method comprising: selectively outputting a first output signal within a first frequency band according to a switch control signal, wherein the first output signal is output by a first voltage-controlled oscillator according to a control voltage; Selectively output a second frequency-divided signal according to the switch control signal, wherein the second frequency-divided signal is frequency-divided from a second output signal in a second frequency band, and the second output signal is a second voltage-controlled oscillation According to the output of the control voltage, the first frequency band does not completely overlap with the second frequency band; selectively divide the frequency of the first output signal or the second frequency division signal according to the switch control signal, and output a first frequency division signal; detecting a phase difference between the first frequency-divided signal and a reference signal, and outputting a phase difference signal; outputting the control voltage according to the phase difference signal; and The control voltage selectively drives the first or second voltage-controlled oscillator according to the switch control signal. 27. The multi-band signal processing method according to claim 26, wherein the switch control signal controls the circuit path for transmitting the control voltage and the first output signal to be turned on or off, so that the first voltage-controlled oscillator outputs or The first output signal is not output, and the switch control signal controls the circuit path for transmitting the control voltage and the second frequency division signal to be turned on or off, so that a second division coupled to the second voltage controlled oscillator The frequency converter outputs or does not output the second frequency-divided signal. 28. The multi-band signal processing method as claimed in claim 27, wherein the switch control signal controls the power supply of the first voltage-controlled oscillator so that the first voltage-controlled oscillator outputs or does not output the first output signal, And the switch control signal controls the power supply to the second voltage-controlled oscillator and the second frequency divider so that the second frequency divider outputs or does not output the second frequency division signal. 29. The multi-band signal processing method as claimed in claim 26, wherein the switch control signal controls the power supply of the first voltage-controlled oscillator so that the first voltage-controlled oscillator outputs or does not output the first output signal, And the switch control signal controls the power supply to the second voltage-controlled oscillator and a second frequency divider coupled to the second voltage-controlled oscillator so that the second frequency divider outputs or does not output the second Frequency division signal. 30. The multi-band signal processing method as claimed in claim 26, further comprising: receiving an input signal; The first or second output signal is mixed with the input signal according to the switch control signal. 31. A multi-band signal processing method, comprising: selectively outputting a first output signal within a first frequency band according to a switch control signal, wherein the first output signal is output by a first voltage-controlled oscillator according to a control voltage; Selectively output a second frequency-divided signal according to the switch control signal, wherein the second frequency-divided signal is frequency-divided from a second output signal in a second frequency band, and the second output signal is a second voltage-controlled oscillation According to the output of the control voltage, the first frequency band does not completely overlap with the second frequency band; selectively divide the frequency of the first output signal or the second frequency division signal according to the switch control signal, and output a first frequency division signal; detecting a phase difference between the first frequency-divided signal and a reference signal, and outputting a phase difference signal; generating a filter signal according to the phase difference signal; adding the filtered signal to an input signal to generate the control voltage; and The control voltage selectively drives the first or second voltage-controlled oscillator according to the switch control signal. 32. The multi-band signal processing method according to claim 31, wherein the switch control signal controls the circuit path for transmitting the control voltage and the first output signal to be turned on or off, so that the first voltage-controlled oscillator outputs or The first output signal is not output, and the switch control signal controls the circuit path for transmitting the control voltage and the second frequency division signal to be turned on or off, so that a second division coupled to the second voltage controlled oscillator The frequency converter outputs or does not output the second frequency-divided signal. 33. The multi-band signal processing method as claimed in claim 32, wherein the switch control signal controls the power supply of the first voltage-controlled oscillator so that the first voltage-controlled oscillator outputs or does not output the first output signal, And the switch control signal controls the power supply to the second voltage-controlled oscillator and the second frequency divider so that the second frequency divider outputs or does not output the second frequency division signal. 34. The multi-band signal processing method as claimed in claim 31, wherein the switch control signal controls the power supply of the first voltage-controlled oscillator so that the first voltage-controlled oscillator outputs or does not output the first output signal, And the switch control signal controls the power supply to the second voltage-controlled oscillator and a second frequency divider coupled to the second voltage-controlled oscillator so that the second frequency divider outputs or does not output the second Frequency division signal. 35. A multi-band electronic device comprising: A phase detector, receiving a reference signal and a frequency signal, detecting the phase difference between the frequency signal and the reference signal and outputting a phase difference signal; A loop filter, coupled to the phase detector, outputs a control voltage according to the phase difference signal; A first voltage-controlled oscillator, coupled to the loop filter, outputs a first output signal within a first frequency band when receiving the control voltage; A first frequency divider, coupled to the first voltage-controlled oscillator, when receiving the first output signal, divides the first output signal to output a first frequency-divided signal; A second voltage-controlled oscillator, coupled to the loop filter, outputs a second output signal within a second frequency band when receiving the control voltage; A second frequency divider, coupled to the second voltage-controlled oscillator, when receiving the second output signal, divides the second output signal to output a second frequency-divided signal; and A selection device is coupled to the first and second frequency-divided signals, and determines to output the first or second frequency-divided signal as the frequency signal according to the control of a switch control signal. 36. The multi-band electronic device as claimed in claim 35, wherein the selection device comprises: a first switch disposed between the first frequency divider and the phase detector; and a second switch disposed between Between the second frequency divider and the phase detector. 37. The multi-band electronic device as claimed in claim 35, further comprising a third switch disposed between the loop filter and the first voltage-controlled oscillator, or between the first voltage-controlled oscillator and the first branch between frequency converters; whether the third switch is turned on is controlled by the switch control signal. 38. The multi-band electronic device as claimed in claim 37, further comprising a fourth switch disposed between the loop filter and the second voltage-controlled oscillator, or between the second voltage-controlled oscillator and the second branch between frequency converters; whether the fourth switch is turned on is controlled by the switch control signal, and is not turned on at the same time as the third switch. 39. The multi-band electronic device as claimed in claim 35, further comprising: a fifth switch coupled to the power supply path of the first voltage-controlled oscillator, and a sixth switch coupled to the power supply of the second voltage-controlled oscillator Path; wherein, the fifth and sixth switches are controlled by the switch control signal, when the selection device outputs the first frequency division signal, the sixth switch is not turned on, so as to cut off the second voltage-controlled oscillator Power supply; when the selection device outputs the second frequency-divided signal, the fifth switch is not turned on, so as to cut off the power supply of the first voltage-controlled oscillator.

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