JP2018088591A - Radio communication apparatus and modulation degree adjustment method of local oscillation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication apparatus capable of adjusting the frequency modulation degree of a reference signal outputted from a first oscillator same as that of a local oscillation signal outputted from a second oscillator, without using an external measuring device.SOLUTION: A VCXO1 in a local oscillation circuit oscillates a reference signal having a reference frequency. A VCO4 included in a phase synchronization loop of the local oscillation circuit oscillates a local oscillation signal in phase synchronism with the reference signal. The VCXO1 and the VCO4 perform frequency modulation of the reference signal and the local oscillation signal, respectively. An AC component extraction circuit 14 extracts a voltage supplied from a loop filter 3 included in the phase synchronization loop to the VCO4, or an AC voltage component superposed on the voltage extracted from the inside of the loop filter 3. A central operation unit 10 adjusts the frequency modulation degrees of the reference signal and the local oscillation signal, so that the AC voltage component has a predetermined size or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless communication apparatus including a local oscillation circuit and a modulation degree adjustment method for the local oscillation circuit.

  A wireless communication apparatus employing a frequency modulation system includes a modulation circuit including a local oscillation circuit in order to frequency modulate a voice or data transmission signal.

  As described in Patent Document 1, as a local oscillation circuit used in a wireless communication device, a voltage-controlled crystal oscillator (VCXO) that oscillates a reference signal and a voltage control that oscillates a local oscillation signal. There is a variable reactance modulation type local oscillation circuit including an oscillator (VCO: Voltage-Controlled Oscillator).

JP 2010-200172 A

  In the local oscillation circuit of the variable reactance modulation method, it is necessary to adjust the frequency modulation degree of the reference signal output from the first oscillator and the frequency modulation degree of the local oscillation signal output from the second oscillator to be the same. . Conventionally, as described in Patent Document 1, in order to determine whether or not the frequency modulation degree is appropriately adjusted, an external measurement device is connected to the wireless communication device and output from the wireless communication device. The frequency modulation degree of the modulation signal to be generated must be measured.

  It is not preferable to use an external measurement device because it is costly to prepare an external measurement device at the manufacturing site or repair site of the wireless communication device.

  In the present invention, the frequency modulation degree of the reference signal output from the first oscillator and the frequency modulation degree of the local oscillation signal output from the second oscillator can be adjusted to be the same without using an external measurement device. An object of the present invention is to provide a wireless communication device and a method for adjusting the modulation degree of a local oscillation circuit.

  The present invention includes a first oscillator that oscillates a reference signal having a reference frequency, a second oscillator that oscillates a local oscillation signal that is phase-synchronized with the reference signal, and a voltage that determines an oscillation frequency of the local oscillation signal. A loop filter supplied to the second oscillator, a first frequency divider that divides the local oscillation signal, a second frequency divider that divides the reference signal, and an output from the first frequency divider A phase comparator that compares the phase of the first frequency-divided signal and the second frequency-divided signal output from the second frequency divider, and outputs a pulse signal corresponding to the phase difference; and the pulse signal A phase-locked loop control circuit having a charge pump for charging and discharging the loop filter according to the frequency, a first frequency modulation means for frequency-modulating the reference signal, and a second frequency modulation means for frequency-modulating the local oscillation signal And the loop figure An AC component extraction circuit for extracting an AC voltage component superimposed on a voltage supplied to the second oscillator or a voltage extracted from the inside of the loop filter, and an AC voltage component extracted by the AC component extraction circuit is a predetermined voltage. There is provided a radio communication apparatus comprising frequency modulation degree control means for controlling the frequency modulation degree by each of the first and second frequency modulation means so as to be smaller than the size.

  The present invention includes a first oscillator that oscillates a reference signal having a reference frequency, a second oscillator that oscillates a local oscillation signal that is phase-synchronized with the reference signal, and a voltage that determines an oscillation frequency of the local oscillation signal. A loop filter supplied to the second oscillator, a first frequency divider that divides the local oscillation signal, a second frequency divider that divides the reference signal, and an output from the first frequency divider A phase comparator that compares the phase of the first frequency-divided signal and the second frequency-divided signal output from the second frequency divider, and outputs a pulse signal corresponding to the phase difference; and the pulse signal A phase-locked loop control circuit having a charge pump for charging and discharging the loop filter in response to the first frequency-dividing ratio by the first frequency divider and the second frequency-dividing circuit. Either one of the second division ratio by the frequency divider or A first frequency modulation means for frequency modulating the local oscillation signal by supplying a division ratio indicating signal for changing both; a second frequency modulation means for further frequency modulating the local oscillation signal; and the loop An AC component extraction circuit that extracts an AC voltage component that is superposed on a voltage that the filter supplies to the second oscillator or a voltage that is extracted from the inside of the loop filter, and an AC voltage component that is extracted by the AC component extraction circuit is predetermined. There is provided a radio communication apparatus comprising frequency modulation degree control means for controlling the frequency modulation degree by each of the first and second frequency modulation means so as to be smaller than the size.

  The present invention provides a local oscillation in which a first oscillator in a local oscillation circuit oscillates a reference signal having a reference frequency, and a second oscillator included in a phase locked loop in the local oscillation circuit is phase-synchronized with the reference signal. A signal is oscillated, the reference signal is frequency-modulated, the local oscillation signal is frequency-modulated, and a voltage supplied to the second oscillator by the loop filter included in the phase-locked loop or taken out from the inside of the loop filter An AC voltage component to be superimposed on the voltage is extracted, and the frequency modulation degree of the reference signal and the frequency modulation degree of the local oscillation signal are adjusted so that the extracted AC voltage component is a predetermined magnitude or less. A modulation degree adjusting method for a local oscillation circuit is provided.

  According to the method of adjusting the modulation degree of the wireless communication apparatus and the local oscillation circuit of the present invention, the frequency modulation degree of the reference signal output from the first oscillator and the second oscillator are output without using an external measurement device. The frequency modulation degree of the local oscillation signal can be adjusted to be the same.

It is a block diagram which shows the radio | wireless communication apparatus of 1st Embodiment. It is a block diagram which shows the specific structure of a PLL control circuit. It is a circuit diagram which shows the 1st structural example of a loop filter. It is a circuit diagram which shows the 2nd structural example of a loop filter. It is a circuit diagram which shows the 3rd structural example of a loop filter. It is a wave form diagram which shows an example of a modulation signal. It is a characteristic view showing a state where the frequency modulation degree of the reference signal output from the VCXO and the frequency modulation degree of the local oscillation signal output from the VCO are not the same. It is a characteristic view showing a state where the frequency modulation degree of the reference signal output from the VCXO and the frequency modulation degree of the local oscillation signal output from the VCO are the same. FIG. 10 is a characteristic diagram showing an AC voltage component superimposed on a VCO voltage (loop filter voltage) when the frequency modulation degree of the reference signal output from the VCXO and the frequency modulation degree of the local oscillation signal output from the VCO are not the same. It is a characteristic diagram which shows the DC voltage which the VCO voltage (loop filter voltage) exhibits when the frequency modulation degree of the reference signal output from the VCXO and the frequency modulation degree of the local oscillation signal output from the VCO are the same. It is a block diagram which shows the radio | wireless communication apparatus of 2nd Embodiment. It is a block diagram which shows the radio | wireless communication apparatus of 3rd Embodiment. It is a block diagram which shows the radio | wireless communication apparatus of 4th Embodiment. It is a block diagram which shows the radio | wireless communication apparatus of 5th Embodiment. It is a block diagram which shows the radio | wireless communication apparatus of 6th Embodiment. It is a block diagram which shows the radio | wireless communication apparatus of 7th Embodiment. It is a block diagram which shows the radio | wireless communication apparatus of 8th Embodiment. It is a flowchart which shows the modulation degree adjustment method of the local oscillation circuit of one Embodiment.

  Hereinafter, the radio communication apparatus of each embodiment and the modulation degree adjustment method of the local oscillation circuit of one embodiment will be described with reference to the accompanying drawings.

<Wireless Communication Device of First Embodiment>
In FIG. 1, a voltage controlled crystal oscillator 1 (hereinafter referred to as VCXO1) oscillates a reference signal having a predetermined reference frequency. VCXO1 is an example of a first oscillator. The VCXO 1 oscillates a reference signal having a frequency corresponding to the voltage input to the voltage input terminal 1a. If a modulation signal whose voltage is variable is input to the voltage input terminal 1a, the VCXO 1 can oscillate a reference signal whose frequency is modulated. The first oscillator may be a temperature-compensated voltage controlled crystal oscillator (VC-TCXO).

  A phase looked loop (PLL) control circuit 2 receives a reference signal and a local oscillation signal output from a voltage controlled oscillator (hereinafter referred to as VCO 4) as a negative feedback signal. VCO 4 is a second oscillator. The VCO 4 has a voltage input terminal 4a.

  As shown in FIG. 2, the PLL control circuit 2 includes frequency dividers 21 and 22, a phase comparator 23, and a charge pump 24. The frequency divider 21 supplies a first frequency-divided signal obtained by dividing the negative feedback signal by 1 / N to the phase comparator 23. N is a predetermined number exceeding 1. The frequency divider 22 supplies the second frequency-divided signal obtained by dividing the reference signal by 1 / R to the phase comparator 23. R is a predetermined number of 1 or more.

  The phase comparator 23 compares the phase of the first frequency-divided signal and the second frequency-divided signal, and generates a pulse signal corresponding to the phase difference. The charge pump 24 charges and discharges the loop filter 3 according to the pulse signal. Specifically, for example, the charge pump 24 charges a capacitor included in the loop filter 3 when the pulse signal is positive, and generates a charge pump current that sucks current from the capacitor included in the loop filter 3 when the pulse signal is negative. To the loop filter 3.

  The loop filter 3 can be configured by connecting resistors R1 and R2 and capacitors C1 to C3 as shown in FIGS. 3A to 3C. The loop filter 3 supplies the VCO voltage Vvco, which is an analog voltage from which pulse noise has been removed, to the VCO 4. When the PLL is phase-synchronized, the VCO voltage Vvco is a DC voltage.

  The VCO 4 oscillates a local oscillation signal having a predetermined frequency in accordance with the input VCO voltage Vvco. The oscillation frequency of the local oscillation signal is determined by the VCO voltage Vvco. The local oscillation signal is supplied to the transmission / reception circuit 20 and supplied to the frequency divider 21 as a negative feedback signal. The VCO 4 can oscillate a local oscillation signal whose frequency is modulated when a modulation signal whose voltage is varied is inputted to the voltage input terminal 4a.

  The PLL control circuit 2, the loop filter 3, and the VCO 4 constitute a PLL. The VCXO 1, the PLL control circuit 2, the loop filter 3, and the VCO 4 constitute a variable reactance modulation type local oscillation circuit. Due to the phase synchronization by the PLL, the VCO 4 outputs a stable local oscillation signal having a constant frequency that is phase-synchronized with the reference signal output from the VCXO 1. Note that the PLL control circuit 2 may be formed of an integrated circuit.

  In FIG. 1, when the wireless communication apparatus is used, an audio signal output from a microphone (not shown) is supplied to the baseband processing unit 11 as indicated by a dashed arrow. The baseband processing unit 11 outputs a modulation signal corresponding to the audio signal. The modulation level adjustment unit 12 adjusts the modulation level of the modulation signal output from the baseband processing unit 11 and supplies it to the voltage input terminal 1 a and the modulation level adjustment unit 13 of the VCXO 1. The modulation level adjustment unit 13 further adjusts the modulation level of the modulation signal output from the modulation level adjustment unit 12 and supplies it to the voltage input terminal 4a of the VCO 4.

  The modulation level adjustment units 12 and 13 can be configured by a variable resistor or an electronic volume that attenuates the amplitude of the input modulation signal.

  VCXO1 modulates the reference signal with the input modulation signal, and VCO4 modulates the local oscillation signal with the input modulation signal. The local oscillation circuit, the baseband processing unit 11, and the modulation level adjustment units 12 and 13 constitute a modulation circuit that modulates a modulation signal such as an audio signal.

  When adjusting the frequency modulation degree (frequency deviation amount) of VCXO1 and VCO4 in the local oscillation circuit to be the same, the baseband processing unit 11 is based on an instruction from the central processing unit 10 connected by the data bus Db. A predetermined modulation signal is output. For example, the baseband processing unit 11 outputs a rectangular wave modulation signal as shown in FIG.

  The modulation signal output from the baseband processing unit 11 when adjusting the local oscillation circuit may be other than a rectangular wave such as a sine wave, or any modulation signal whose voltage changes periodically. The frequency and amplitude of the modulation signal output from the baseband processing unit 11 are arbitrary.

  The baseband processing unit 11 can be configured by a DSP (Digital Signal Processor), and the baseband processing unit 11 can output an arbitrary modulation signal based on control by the central processing unit 10.

  The central processing unit 10 is connected by a PLL control circuit 2, modulation level adjustment units 12 and 13, a detection unit 15 described later, and a data bus Db. The central processing unit 10 instructs the degree of modulation in the modulation level adjusting units 12 and 13. The central processing unit 10 instructs the frequency division ratio N of the frequency divider 21 and the frequency division ratio R of the frequency divider 22 in the PLL control circuit 2.

  When receiving or transmitting an audio signal having a predetermined frequency when the wireless communication apparatus is used, the central processing unit 10 indicates the frequency division ratios N and R corresponding to the reception frequency or the transmission frequency and establishing the PLL phase synchronization. Execute the tuning operation. That is, the central processing unit 10 can set an operating frequency for receiving or transmitting by setting the frequency division ratios N and R.

  In the variable reactance modulation type local oscillation circuit including VCXO1 and VCO4, as shown in FIGS. 5A and 5B, the low frequency band side at the modulation frequency is the modulation band by VCXO1, and the high frequency side is the modulation band by VCO4. It is. The frequency band in which both are overlapped is an overlapping modulation band by both VCXO1 and VCO4.

  FIG. 5A shows a state in which the frequency modulation degree by VCXO1 and the frequency modulation degree by VCO4 are not the same. FIG. 5B shows a state where the frequency modulation degree by VCXO1 and the frequency modulation degree by VCO4 are the same.

  In FIG. 1, the AC component extraction circuit 14 is supplied with the VCO voltage Vvco output from the loop filter 3 as shown in FIG. 3A. Alternatively, the AC component extraction circuit 14 is supplied with a loop filter voltage V31 between the resistor R2 and the capacitor C2 extracted from the inside of the loop filter 3, as shown in FIG. 3B. The AC component extraction circuit 14 is configured by a capacitor 141.

  In the state shown in FIG. 5A where the frequency modulation degree by VCXO1 and the frequency modulation degree by VCO4 are not the same, an AC voltage component is superimposed on the VCO voltage Vvco (loop filter voltage V31) as shown in FIG. 6A. In the state shown in FIG. 5B in which the frequency modulation degree by VCXO1 and the frequency modulation degree by VCO4 are the same, the AC voltage component is not superimposed on the VCO voltage Vvco (loop filter voltage V31), and the VCO as shown in FIG. 6B. The voltage Vvco (loop filter voltage V31) is a DC voltage.

  The output of the AC component extraction circuit 14 is supplied to the detection unit 15. When the frequency modulation degree by VCXO1 and the frequency modulation degree by VCO4 are not the same, an AC voltage component is supplied to the detection unit 15, and when the frequency modulation degree by VCXO1 and the frequency modulation degree by VCO4 are the same, the detection unit 15 Almost no AC voltage component is supplied.

  FIG. 3C shows a configuration in which the loop filter voltage V32 between the capacitor C2 and the resistor R2 is taken out by reversing the connection between the resistor R2 and the capacitor C2 as compared with FIGS. According to this configuration, since the capacitor C2 functions as an AC component extraction circuit (differential circuit), the capacitor C2 can be shared as a capacitor in the AC component extraction circuit 14. Therefore, when the loop filter 3 has the configuration shown in FIG. 3C, the AC component extraction circuit 14 can be omitted, and the loop filter voltage V32 may be supplied directly to the detection unit 15. In the following description, the loop filter 3 is assumed to have the configuration shown in FIG. 3A or 3B.

  The detection unit 15 detects an AC voltage component and supplies detection information to the central processing unit 10. The detection information generated by the detection unit 15 is a digital value having a value corresponding to the magnitude of the AC voltage component. The central processing unit 10 adjusts the modulation levels of the modulation level adjustment units 12 and 13 so that the value of the detection information supplied from the detection unit 15 is minimized.

  As an example, the central processing unit 10 fixes the modulation level of the modulation level adjustment unit 12 to a predetermined value and adjusts the modulation level of the modulation level adjustment unit 13 so that the value of the detection information is minimized. At this time, the central processing unit 10 may decrease the modulation level in order from the state where the modulation level of the modulation level adjustment unit 13 is maximized until the value of the detection information is minimized.

  The central processing unit 10 may fix the modulation level of the modulation level adjustment unit 13 to a predetermined value and adjust the modulation level of the modulation level adjustment unit 12 so that the value of the detection information is minimized. The modulation levels of both the level adjusting units 12 and 13 may be adjusted.

<Wireless Communication Device of Second Embodiment>
A wireless communication apparatus according to the second embodiment will be described with reference to FIG. 7, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 7, the AC component extraction circuit 14 includes an amplifier 142 after the capacitor 141. In the wireless communication apparatus according to the second embodiment, the AC component extraction circuit 14 includes the amplifier 142, so that the detection unit 15 can improve the accuracy with which the AC voltage component is detected.

<Wireless Communication Device of Third Embodiment>
A wireless communication apparatus according to the third embodiment will be described with reference to FIG. In FIG. 8, the same parts as those in FIG. In FIG. 8, a rectifier circuit 16 including diodes D <b> 1 and D <b> 2 is connected between the AC component extraction circuit 14 and the detection unit 15. The rectifier circuit 16 rectifies the AC voltage component extracted by the AC component extraction circuit 14 and converts it into a DC voltage.

  The detection unit 15 supplies a digital value having a value corresponding to the magnitude of the DC voltage to the central processing unit 10 as detection information. Similar to the first embodiment, the central processing unit 10 adjusts the modulation levels of the modulation level adjustment units 12 and 13 so that the value of the detection information supplied from the detection unit 15 is minimized.

<Wireless Communication Device of Fourth Embodiment>
A wireless communication apparatus according to the fourth embodiment will be described with reference to FIG. 9, parts that are the same as those in FIG. 1 are given the same reference numerals, and explanation thereof is omitted. A wireless communication apparatus using a half-duplex communication system includes a PTT (Push To Talk) switch (not shown), and is configured to transmit an audio signal when the PTT switch is pressed.

  In order to realize a hands-free function, the wireless communication apparatus has a VOX (Voice-operated Transmit) function that automatically switches to a state equivalent to pressing the PTT switch when sound from the microphone is detected. There is.

  The wireless communication apparatus according to the fourth embodiment is configured to supply the output of the AC component extraction circuit 14 to the detection unit 15 using a VOX circuit. In FIG. 9, the switch 18 is connected to the terminal Ta connected to the microphone 17 when the wireless communication device is used, and connected to the AC component extraction circuit 14 when adjusting the local oscillation circuit, under the control of the central processing unit 10. Connected to terminal Tb.

  A VOX circuit 19 is provided between the switch 18 and the detection unit 15. The VOX circuit 19 includes an amplifier 191 and a rectifier circuit 192 composed of diodes D3 and D4. The detection unit 15 is an audio signal detection unit for activating the VOX function.

  When sound is input to the microphone 17 during use of the wireless communication device, the sound signal is input to the VOX circuit 19 via the switch 18. The VOX circuit 19 amplifies and rectifies the audio signal and converts it into a DC voltage. If the DC voltage is equal to or greater than a predetermined threshold, the detection unit 15 determines that sound has been input to the microphone 17 and supplies detection information to the central processing unit 10. The central processing unit 10 switches the wireless communication device to a state equivalent to pressing the PTT switch.

  At the time of adjustment of the local oscillation circuit, the output of the AC component extraction circuit 14 is input to the VOX circuit 19 via the switch 18. The VOX circuit 19 amplifies and rectifies the AC voltage component extracted by the AC component extraction circuit 14 and converts it into a DC voltage. The detection unit 15 supplies a digital value having a value corresponding to the magnitude of the DC voltage to the central processing unit 10 as detection information.

  Similar to the first embodiment, the central processing unit 10 adjusts the modulation levels of the modulation level adjustment units 12 and 13 so that the value of the detection information supplied from the detection unit 15 is minimized.

<Wireless Communication Device of Fifth Embodiment>
A wireless communication apparatus according to the fifth embodiment will be described with reference to FIG. 10, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. The wireless communication device includes a noise squelch circuit that blocks noise when there is no audio signal in the received wave and harsh noise occurs. The wireless communication apparatus of the fifth embodiment is configured to supply the output of the AC component extraction circuit 14 to the detection unit 15 using a noise squelch circuit.

  In FIG. 10, an antenna 110 is connected to an antenna connection terminal 101 of a housing 100 that houses a wireless communication device. The local switch 201, the amplifiers 202 to 204, the antenna switch 205, the reception front end 206, and the detection circuit 207 constitute the transmission / reception circuit 20.

  When the transmission / reception circuit 20 operates as a transmission circuit, a transmission signal output from the VCO 4 is sequentially input to the amplifiers 202 to 204 via the local switch 201 and amplified, and is transmitted via the antenna switch 205 and the antenna connection terminal 101. It is transmitted from the antenna 110.

  When the transmission / reception circuit 20 operates as a reception circuit, the reception front end 206 receives the local oscillation signal output from the VCO 4 via the local switch 201 and the antenna 110 via the antenna connection terminal 101 and the antenna switch 205. Received signal is input.

  The reception front end 206 mixes the local oscillation signal having the frequency to be received and the reception signal to generate an intermediate frequency signal (IF signal). The detection circuit 207 detects the IF signal and outputs an audio signal having a frequency to be received. The audio signal is supplied to the audio signal processing unit 31 and the terminal Ta of the switch 32.

  The switch 32 is connected to the terminal Ta connected to the detection circuit 207 when the wireless communication device is used, and is connected to the terminal Tb connected to the AC component extraction circuit 14 when adjusting the local oscillation circuit, under the control of the central processing unit 10. Connected.

  A noise squelch detection circuit 33 is provided between the switch 32 and the detection unit 15. The noise squelch detection circuit 33 includes an amplifier 331 and a rectifier circuit 332 including diodes D5 and D6. The detection unit 15 is an audio signal detection unit for determining whether or not to activate the noise squelch function.

  When an audio signal is input to the noise squelch detection circuit 33 via the switch 32 when using the wireless communication apparatus, the noise squelch detection circuit 33 amplifies and rectifies the audio signal and converts it into a DC voltage. If the DC voltage is equal to or greater than a predetermined threshold, the detection unit 15 determines that an audio signal is present in the received wave, and supplies detection information indicating that the audio signal is present to the central processing unit 10.

  The central processing unit 10 controls the switch 34 to be in an ON state so that the audio signal output from the audio signal processing unit 31 is output from the speaker 35.

  If the DC voltage is less than the threshold value, the detection unit 15 determines that there is no audio signal in the received wave, and supplies detection information indicating that no audio signal exists to the central processing unit 10. The central processing unit 10 controls the switch 34 to be in an OFF state so that noise is not output from the speaker 35.

  When adjusting the local oscillation circuit, the output of the AC component extraction circuit 14 is input to the noise squelch detection circuit 33 via the switch 32. The noise squelch detection circuit 33 amplifies and rectifies the AC voltage component extracted by the AC component extraction circuit 14 and converts it into a DC voltage. The detection unit 15 supplies a digital value having a value corresponding to the magnitude of the DC voltage to the central processing unit 10 as detection information.

  Similar to the first embodiment, the central processing unit 10 adjusts the modulation levels of the modulation level adjustment units 12 and 13 so that the value of the detection information supplied from the detection unit 15 is minimized.

<Wireless Communication Device of Sixth Embodiment>
A wireless communication apparatus according to the sixth embodiment will be described with reference to FIG. In FIG. 11, the same parts as those in FIG. In the wireless communication devices of the first to fifth embodiments, modulation level adjustment units 12 and 13 are provided outside the baseband processing unit 11 to adjust the frequency modulation degrees of the VCXO 1 and the VCO 4.

  The baseband processing unit 11 may be configured to incorporate the functions of the modulation level adjustment units 12 and 13. The central processing unit 10 instructs the baseband processing unit 11 to output a modulation signal. The central processing unit 10 also instructs the baseband processing unit 11 about the modulation level of the modulation signal supplied to the VCXO 1 and the modulation level of the modulation signal supplied to the VCO 4.

  The baseband processing unit 11 adjusts the modulation signal to the modulation level for VCXO1 designated by the central processing unit 10, performs D / A conversion, and supplies the modulation signal to the VCXO1. Further, the baseband processing unit 11 adjusts the modulation signal to the modulation level for VCO 4 instructed by the central processing unit 10, performs D / A conversion, and supplies the modulation signal to the VCO 4.

  As in the first embodiment, the central processing unit 10 adjusts the modulation levels for the VCXO 1 and the VCO 4 by the baseband processing unit 11 so that the value of the detection information supplied from the detection unit 15 is minimized.

<Wireless Communication Device of Seventh Embodiment>
A wireless communication apparatus according to the seventh embodiment will be described with reference to FIG. In FIG. 12, the same parts as those of FIG. In FIG. 12, the baseband processing unit 11 and the PLL control circuit 2 are connected by a data bus Db.

  In the first to sixth embodiments, the modulation signal is supplied to the voltage input terminal 1a of the VCXO 1 to modulate the frequency of the reference signal. In the seventh embodiment, instead, the baseband processing unit 11 controls the PLL control circuit 2 to modulate the frequency of the local oscillation signal output from the VCO 4. Instead of the baseband processing unit 11 controlling the PLL control circuit 2, the central processing unit 10 may control the PLL control circuit 2.

  If one or both of the frequency division ratio N of the frequency divider 21 and the frequency division ratio R of the frequency divider 22 in the PLL control circuit 2 are changed, the local oscillation signal is frequency-modulated. This is equivalent to performing the channel selection operation in the first to sixth embodiments corresponding to the modulation signal. Similarly to the frequency modulation of the reference signal in the first to sixth embodiments, either the frequency division ratio N of the frequency divider 21 or the frequency division ratio R of the frequency divider 22 in the PLL control circuit 2. The modulation band of frequency modulation by changing both of them is the modulation band on the low frequency band side. Therefore, the baseband processing unit 11 responds to the change in the amplitude of the modulation signal in FIG. 4 and outputs a digital value division ratio instruction signal that changes either or both of the division ratio N and the division ratio R. What is necessary is just to supply to the PLL control circuit 2.

  If the modulation signal is a sine wave signal, the baseband processing unit 11 changes one or both of the division ratio N and the division ratio R so as to correspond to the frequency modulation degree indicated by the sine wave signal. What is necessary is just to supply the frequency division ratio instruction signal to the PLL control circuit 2.

  Similar to the first embodiment, the central processing unit 10 uses the modulation level for the VCXO 1 by the baseband processing unit 11 and the modulation level adjustment unit 13 so that the value of the detection information supplied from the detection unit 15 is minimized. Adjust the modulation level. The seventh embodiment is a configuration suitable when the PLL control circuit 2 is formed of an integrated circuit and includes a channel selection instruction input terminal and an adjustment input terminal. In the seventh embodiment, since the oscillation frequency of the reference signal is not modulated, a crystal oscillator (XO: Crystal Oscillator) or a temperature compensated crystal oscillator (TCXO: Temperature-Compensated Crystal Oscillator) may be used.

<Wireless Communication Device of Eighth Embodiment>
A wireless communication apparatus according to the eighth embodiment will be described with reference to FIG. In FIG. 13, the same parts as those in FIG. In FIG. 13, the A / D converter 41 performs A / D conversion on the VCO voltage Vvco (loop filter voltage V31) output from the loop filter 3, and the AC included in the central processing unit 10 via the data bus Db. It supplies to the component extraction part 50. The AC component extraction unit 50 extracts an AC component by performing a differentiation process on the A / D converted VCO voltage Vvco.

  The central processing unit 10 incorporates the function of the detection unit 15, detects the AC voltage component extracted by the AC component extraction unit 50, and generates detection information. Similar to the first embodiment, the central processing unit 10 adjusts the modulation levels of the modulation level adjusting units 12 and 13 so that the value of the detection information is minimized.

  As described above, the wireless communication devices of the first to sixth and eighth embodiments have the first frequency modulation means for frequency-modulating the reference signal output from the VCXO 1 and the local oscillation signal output from the VCO 4 as the frequency. Second frequency modulation means for modulating. The wireless communication apparatus according to the seventh embodiment includes first frequency modulation means for frequency-modulating a local oscillation signal output from the VCO 4, and second frequency modulation means for further frequency-modulating the local oscillation signal output from the VCO 4. Is provided.

  In the wireless communication devices of the first to sixth and eighth embodiments, the configuration for supplying the modulation signal to the voltage input terminal 1a of the VCXO 1 functions as the first frequency modulation means. In the wireless communication apparatus according to the seventh embodiment, the configuration for supplying the frequency division ratio instruction signal to the PLL control circuit 2 functions as the first frequency modulation means. In the wireless communication devices of the first to eighth embodiments, the configuration for supplying the modulation signal to the voltage input terminal 4a of the VCO 4 functions as the second frequency modulation means.

  The wireless communication apparatuses according to the first to eighth embodiments adjust the frequency modulation degrees by the first and second frequency modulation means so that the AC voltage component extracted by the AC component extraction circuit 14 is not more than a predetermined magnitude. Frequency modulation degree control means for controlling is provided.

  In the wireless communication devices of the first to fifth and eighth embodiments, the central processing unit 10 and the modulation level adjustment units 12 and 13 function as frequency modulation degree control means. In the wireless communication apparatus of the sixth embodiment, the central processing unit 10 and the baseband processing unit 11 function as frequency modulation degree control means. In the wireless communication device of the seventh embodiment, the central processing unit 10, the baseband processing unit 11, and the modulation level adjusting unit 13 function as a frequency modulation degree control unit.

  As described above, various configurations of the frequency modulation unit and the frequency modulation degree control unit can be considered, and the hardware configuration of the modulation circuit including the local oscillation circuit is not particularly limited. The first to eighth embodiments may be appropriately combined except for contradictory combinations.

<Method for Adjusting Degree of Modulation of Local Oscillator of One Embodiment>
A method for adjusting the modulation factor of the local oscillation circuit according to the embodiment will be described with reference to the flowchart shown in FIG. The flowchart shown in FIG. 14 shows a modulation degree adjustment method in a wireless communication apparatus including modulation level adjustment units 12 and 13.

  In FIG. 14, the central processing unit 10 sets a predetermined gain in the modulation level adjustment unit 12 in step S1. A gain smaller than the maximum gain may be set as the predetermined gain. As a result, the frequency modulation degree of the reference signal output from the VCXO 1 is fixed to a predetermined value. The central processing unit 10 sets the maximum gain in the modulation level adjustment unit 13 in step S2. Thereby, the frequency modulation degree of the local oscillation signal output from the VCO 4 is set to the maximum value.

  The maximum gain value of the modulation level adjustment unit 13 may be a physical maximum value that can be set in the modulation level adjustment unit 13, and is an upper limit value set in the central processing unit 10. May be. By steps S1 and S2, the frequency modulation degree has characteristics as shown in FIG. 5A.

  In step S3, central processing unit 10 determines whether the amplitude of the AC voltage component is equal to or smaller than a predetermined magnitude. The central processing unit 10 may set the magnitude that can be considered that the AC voltage component is hardly superimposed on the VCO voltage Vvco (loop filter voltage V31) as a predetermined magnitude.

  If the amplitude of the AC voltage component is equal to or smaller than the predetermined magnitude (YES), the central processing unit 10 stores the gain set in the modulation level adjustment unit 13 and the fact that the adjustment is normally completed in step S6. To finish the process. If the amplitude of the AC voltage component is not less than or equal to the predetermined magnitude (NO), the central processing unit 10 shifts the process to step S4.

  In step S4, central processing unit 10 determines whether or not the gain of modulation level adjustment unit 13 is the lowest value. The minimum value may be a physical minimum value that can be set in the modulation level adjusting unit 13 or a lower limit value that is set in the central processing unit 10.

  If the gain of the modulation level adjustment unit 13 is the lowest value (YES), the central processing unit 10 stores that the adjustment has been abnormally ended in step S7 and ends the process. If it is stored in the central processing unit 10 that the adjustment has ended abnormally, it can be seen that a problem has occurred that the modulation degree of the local oscillation circuit could not be adjusted during service of the wireless communication device.

  If the gain of the modulation level adjustment unit 13 is not the lowest value (NO), the central processing unit 10 decreases the gain of the modulation level adjustment unit 13 by one step in step S5, and returns the process to step S3. Thereafter, the central processing unit 10 performs steps S3 to S3 until the amplitude of the AC voltage component becomes equal to or smaller than a predetermined magnitude in step S3, or until the gain of the modulation level adjustment unit 13 becomes the minimum value in step S4. The process of S5 is repeated.

  When the amplitude of the AC voltage component becomes equal to or smaller than the predetermined magnitude in step S3 and the central processing unit 10 executes step S6 and ends the processing, as shown in FIG. 5B, the frequency modulation degree by VCXO1 and the frequency by VCO4 The modulation degree is set to be the same.

  The modulation degree adjustment method for the local oscillation circuit may have the following processing (operation). A first oscillator (VCXO1) in the local oscillation circuit oscillates a reference signal having a reference frequency. A second oscillator (VCO 4) included in the phase-locked loop in the local oscillation circuit oscillates a local oscillation signal that is phase-locked with the reference signal. Frequency modulation means frequency modulates the reference signal. Frequency modulation means frequency modulates the local oscillation signal.

  The AC component extraction circuit 14 superimposes the voltage (VCO voltage Vvco) supplied to the second oscillator by the loop filter included in the phase-locked loop or the voltage extracted from the inside of the loop filter (loop filter voltage V31). To extract. The frequency modulation degree control means adjusts the frequency modulation degree of the reference signal and the frequency modulation degree of the local oscillation signal so that the extracted AC voltage component is a predetermined magnitude or less.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention. The modulation degree adjustment method for the local oscillation circuit of the present embodiment can also be used when adjusting the modulation degree of the local oscillation circuit provided in any electronic device other than the wireless communication device.

1 Voltage controlled crystal oscillator (first oscillator)
2 Phase-locked loop control circuit (PLL control circuit)
3 Loop filter 4 Voltage controlled oscillator (second oscillator)
DESCRIPTION OF SYMBOLS 10 Central processing unit 11 Baseband process part 12, 13 Modulation level adjustment part 14 AC component extraction circuit 15 Detection part 21,22 Frequency divider 23 Phase comparator 24 Charge pump

Claims (4)

A first oscillator for oscillating a reference signal having a reference frequency;
A second oscillator that oscillates a local oscillation signal that is phase-synchronized with the reference signal;
A loop filter for supplying a voltage for determining an oscillation frequency of the local oscillation signal to the second oscillator;
A first frequency divider for frequency-dividing the local oscillation signal; a second frequency divider for frequency-dividing the reference signal; the first frequency-divided signal output from the first frequency divider; A phase comparator that compares the phase of the second frequency-divided signal output from the frequency divider and outputs a pulse signal corresponding to the phase difference, and a charge pump that charges and discharges the loop filter according to the pulse signal A phase locked loop control circuit comprising:
First frequency modulation means for frequency modulating the reference signal;
Second frequency modulation means for frequency modulating the local oscillation signal;
An AC component extraction circuit that extracts an AC voltage component superimposed on a voltage supplied by the loop filter to the second oscillator or a voltage extracted from the inside of the loop filter;
Frequency modulation degree control means for controlling the frequency modulation degree by each of the first and second frequency modulation means so that the AC voltage component extracted by the AC component extraction circuit is not more than a predetermined magnitude;
A wireless communication apparatus comprising:   The first oscillator has a first voltage input terminal, and the first frequency modulation means is configured to supply a modulation signal whose voltage periodically changes to the first voltage input terminal, The second oscillator has a second voltage input terminal, and the second frequency modulation means supplies a modulation signal whose voltage periodically changes to the second voltage input terminal. The wireless communication apparatus according to claim 1. A first oscillator for oscillating a reference signal having a reference frequency;
A second oscillator for oscillating a local oscillation signal that is phase-synchronized with the reference signal;
A loop filter for supplying a voltage for determining an oscillation frequency of the local oscillation signal to the second oscillator;
A first frequency divider for frequency-dividing the local oscillation signal; a second frequency divider for frequency-dividing the reference signal; the first frequency-divided signal output from the first frequency divider; A phase comparator that compares the phase of the second frequency-divided signal output from the frequency divider and outputs a pulse signal corresponding to the phase difference, and a charge pump that charges and discharges the loop filter according to the pulse signal A phase locked loop control circuit comprising:
Frequency division that causes the phase-locked loop control circuit to change either or both of the first frequency division ratio by the first frequency divider and the second frequency division ratio by the second frequency divider. A first frequency modulation means for frequency modulating the local oscillation signal by supplying a ratio indicating signal;
Second frequency modulation means for further frequency modulating the local oscillation signal;
An AC component extraction circuit that extracts an AC voltage component superimposed on a voltage supplied by the loop filter to the second oscillator or a voltage extracted from the inside of the loop filter;
Frequency modulation degree control means for controlling the frequency modulation degree by each of the first and second frequency modulation means so that the AC voltage component extracted by the AC component extraction circuit is not more than a predetermined magnitude;
A wireless communication apparatus comprising: A first oscillator in the local oscillator circuit oscillates a reference signal having a reference frequency;
A second oscillator included in a phase-locked loop in the local oscillation circuit oscillates a local oscillation signal phase-synchronized with the reference signal;
Frequency-modulating the reference signal;
Frequency-modulate the local oscillation signal;
Extracting the voltage supplied to the second oscillator by the loop filter included in the phase-locked loop or the AC voltage component superimposed on the voltage taken out from the inside of the loop filter,
A modulation degree adjustment method for a local oscillation circuit, characterized in that the frequency modulation degree of the reference signal and the frequency modulation degree of the local oscillation signal are adjusted so that the extracted AC voltage component is a predetermined magnitude or less. .

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