JPH05160751A - Superheterodyne receiver - Google Patents

Abstract

PURPOSE:To obtain a receiver in which reception mode and band width are automatically set. CONSTITUTION:A data table DTBL in which data DFR corresponding to a reception frequency, data DMD of the reception mode with respect to the reception frequency and data DBW of a band width with respect to the reception frequency are used in pairs is provided. When the reception frequency is set, the data table DTBL is referred and the data DMD in pairs with the reception mode, the data DBW of the band width are extracted from the data table DTBL and the reception mode and the band width are set according to the data DMD of the reception mode and the data DBW of the band width.

Description

Detailed Description of the Invention

[0001]

This invention relates to superheterodyne receivers.

[0002]

2. Description of the Related Art Broadcasting in the medium-wave band uses 531 kHz to 1602 kHz as its frequency band, and uses frequency positions every 9 kHz among them. The broadcast wave signal is a DSB signal.

On the other hand, in the short wave band, a commercial broadcast called a meter band uses a DSB signal, and a communication band outside the broadcast band mainly uses a USB signal. In addition, the LSB signal is used in the amateur radio of 10 MHz or less.

[0004]

As described above, in medium-wave broadcasting, short-wave broadcasting or short-wave communication, the transmission signal is a DSB signal or a USB signal,
It may be an LSB signal. The occupied bandwidth is wide for the DSB signal, and the occupied bandwidth is narrow for the SSB signal.

Therefore, when receiving these medium-wave broadcasting, short-wave broadcasting or short-wave communication, it is necessary to switch the receiving mode to the DSB receiving mode, the USB receiving mode or the LSB receiving mode according to the transmission signal. Furthermore, at this time, the bandwidth of the intermediate frequency amplifier is also
It is necessary to switch according to the bandwidth of the transmission signal.

However, switching the reception mode and the bandwidth in this way is troublesome. Particularly, in a synthesizer receiver, when performing scan reception, it is necessary to stop the scan and switch the reception mode and bandwidth, which reduces the merit of scan reception.

The present invention is intended to solve such a problem.

[0008]

[Means for Solving the Problems] As described above, DS is used in medium-wave broadcasting and commercial broadcasting called meter band.
The B signal is used and its occupied bandwidth is wide. On the other hand, in other short wave communication, a USB signal is used and its occupied bandwidth is narrow.

Also, in shortwave communication, amateur radio is LS
Although using B signals, the frequency bands allowed for this ham radio are known.

The present invention focuses on these points and automatically switches the reception mode and bandwidth according to the reception frequency or the reception band.

That is, in the present invention, when the reference numerals of the respective parts correspond to the embodiments described later, the reception frequency f11
A data table DTBL which is a combination of data DFR corresponding to the received frequency f11, reception mode data DMD corresponding to the reception frequency f11, and bandwidth data DBW corresponding to the reception frequency f11.
To provide. Then, when the reception frequency f11 is set, or when it is set, the data table DTBL is referred to and set, or the reception mode data DMD and the bandwidth data DBW paired with the set reception frequency f11 are set.
From the data table DTBL, and the receiving mode and the bandwidth are set according to the received data DMD of the receiving mode and the data DBW of the bandwidth.

[0012]

When the channel is selected, the data table DTBL is referred to and the reception mode and bandwidth are automatically set to the state corresponding to the reception frequency f11.

[0013]

FIG. 1 shows an example of the present invention. In this example, the present invention is applied to a receiver of the double superheterodyne system. Further, the receiver is a case where the tuning is performed by changing both the first local oscillation frequency and the second local oscillation frequency.

Further, in this example, the reception frequency f11: 150 kHz to 30 MHz (approximately) the first intermediate frequency frequency f13: 55.845 MHz, the second intermediate frequency frequency f15: 455 kHz, and the first local oscillation. By changing the frequency in steps of 1 kHz and the second local oscillation frequency in steps of 100 Hz, the reception frequency f11 is changed to 100 Hz.
This is the case when it can be changed in steps.

That is, the received signal S11 is transmitted to the antenna 11
Is supplied to the first mixer circuit 13 from the high frequency amplifier 12 and the first local oscillation signal S21 is supplied to the mixer circuit 13 from the first local oscillation circuit 21. In this case, the frequency f21 of the local oscillation signal S21 is the reception frequency f11.
On the other hand, f21 = f11 + f13 (1), and f21 = (150 kHz + 55.845 MHz) to (30 MHz + 55.845 MHz) (2) However, the frequency f21 changes like 1 kHz step. It is a thing.

Thus, the received signal S11 is transmitted to the mixer circuit 1
3, the frequency is converted into the first intermediate frequency signal S13 (intermediate frequency f13) by the first local oscillation signal S21.

The signal S13 is supplied to the second mixer circuit 15 through the first intermediate frequency amplifier 14, and the second local oscillation circuit 31 outputs the second local oscillation signal S31.
Are supplied to the mixer circuit 15. In this case, the frequency f31 of the local oscillation signal S31 is f31 = f13−f15 = f21−f11−f15 (3) with respect to the reception frequency f11, and f31 = (55.39 MHz + 0.5 kHz ) To (55.39 MHz-0.4 kHz) (4) However, the frequency f31 changes like a change in 100 Hz steps.

Thus, the first intermediate frequency signal S13 is output to the second local oscillation signal S31 by the second local oscillation signal S31 in the mixer circuit 15.
The frequency is converted into the intermediate frequency signal S15 (intermediate frequency f15).

At the time of receiving the DSB signal (at the time of receiving the medium wave broadcast or the short wave broadcast), the signal S15 from the mixer circuit 15 has a wide band (pass band is ± 6 kHz).
Is supplied to the AM detection circuit 17 through the second intermediate frequency amplifier 16W and the switch circuit 47, the audio signal is demodulated, and this audio signal is passed through the switch circuit 48 to the terminal 18
Taken out.

Further, when the SSB signal is received (when the short-wave communication or the like is received), the intermediate frequency signal S from the mixer circuit 15 is received.
15 is supplied to the balanced mixer circuit 43 through the second intermediate frequency amplifier 16N having a narrow band (pass band is, for example, ± 2.8 kHz) and the switch circuit 47.

When the SSB signal is a USB signal (for general short-wave communication etc.), the frequency f41, for example, the BFO signal S41 of f41 = 457 kHz is taken out from the BFO 41, and this BFO signal S41 is switched. It is supplied to the mixer circuit 43 through the circuit 49.

Thus, from the mixer circuit 43, the USB
An audio signal demodulated from the signal is extracted, and this audio signal is extracted to the terminal 18 through the switch circuit 48.

Further, when the SSB signal is the LSB signal (for amateur radio, etc.), the frequency f42, for example, the BFO signal S42 of f42 = 453 kHz is extracted from the BFO42, and this BFO signal S42 is switched. Through the mixer circuit 43.

Thus, from the mixer circuit 43, the LSB is
An audio signal demodulated from the signal is extracted, and this audio signal is extracted to the terminal 18 through the switch circuit 48.

According to the above construction, the reception frequency f
From the equation (3), 11 is f11 = f21-f31-f15 (5).

Since the frequencies f21 and f31 change the range of the equations (2) and (4) according to the reception frequency f11,
From equation (5), for example, f21 = 150 kHz + 55.845 MHz, f
When 31 = 55.39 MHz + 0.5 kHz, f11 = f21-f31-f15 = (150 kHz + 55.845 MHz)-(55.39 MHz + 0.5 kHz) -455 kHz = 150 kHz-0.5 kHz. Also, f21 = 30 MHz + 55.845 MHz, f31 = 55.3
At 9 MHz-0.4 kHz, f11 = f21-f31-f15 = (30 MHz + 55.845 MHz)-(55.39 MHz-0.4 kHz) -455 kHz = 30 MHz + 0.4 kHz. Therefore, the reception band is approximately 150 kHz to 30 M
It becomes Hz.

Further, according to the equation (5), when the second local oscillation frequency f31 is constant, the first local oscillation frequency f21 is 1k.
If the frequency is changed in Hz steps, the reception frequency f11 changes in 1 kHz steps. When the first local oscillation frequency f21 is constant, if the second local oscillation frequency f31 is changed in 100 Hz steps, the reception frequency f11 changes in 100 Hz steps. It changes with.

Then, the first local oscillation frequency f31 is set to 1 kHz.
The first local oscillation circuit 21 changes to V
It is composed of CO and its VCO 21 is PL
It is configured to form a part of L20.

That is, the VCO is used as the local oscillation circuit 21.
21 is provided, and the oscillation signal of the VCO 21 is supplied to the first mixer circuit 13 as the first local oscillation signal S21, and this signal S21 is supplied to the variable frequency dividing circuit 22 to be a signal having a frequency of 1 / N. The frequency is divided and the divided signal is supplied to the phase comparison circuit 23. Further, an oscillation signal having a reference frequency, for example, a frequency of 1 kHz is taken out from the reference oscillation circuit 24, and this signal is supplied to the phase comparison circuit 23,
The comparison output is passed through the low pass filter 25 to VCO2.
1 as its control voltage.

Therefore, in the steady state, the frequency-divided signal from the frequency-dividing circuit 22 and the oscillation signal of the oscillation circuit 24 have the same frequency. Therefore, the frequency f21 of the oscillation signal S21 at this time is f21 = N × 1. It becomes [kHz]. At this time, equation (5) holds.

Therefore, if the frequency division ratio N is changed by 1 between 55995 and 85845, the local oscillation frequency f21
However, since the range of the equation (2) is changed at 1 kHz intervals, the reception frequency f11 can be changed in steps of 1 kHz.

Further, the second local oscillation frequency f31 is set to 100 Hz.
The second local oscillation circuit 31 changes to V
It is composed of CXO. In this case, VCXO31
As the oscillating element, it is a variable frequency oscillation circuit using a crystal oscillator and a variable capacitance diode, and the output voltage V32 of the D / A converter 32 is supplied to the variable capacitance diode as a control voltage. Then, the oscillation signal of the VCXO 31 is used as the second local oscillation signal S31 in the second mixer circuit 1
5 is supplied.

Therefore, when the predetermined control data D32 is supplied to the D / A converter 42, the oscillation frequency f31 of the oscillation signal S31 of the VCXO 31 changes corresponding to the data D32, so the oscillation frequency f31 is changed by the data D32. (Four)
Within the range of the formula, it can be changed in 100 Hz steps, and the reception frequency f11 can be changed in 100 Hz steps.

Therefore, the predetermined frequency division ratio N and data D
By supplying 32 to the variable frequency dividing circuit 22 and the D / A converter 32, the reception frequency f11 can be changed in 100 Hz steps in the reception band of 150 kHz to 30 MHz.

Further, 50 is a microcomputer for system control, 51 is its CPU, 52
Is a ROM in which various programs are written, 53 is a work area RAM, and 54 is a data holding RAM
Then, these memories 52 to 54 are connected to the CPU 51 through the system bus 59.

In this case, the ROM 52 has, for example, the routine 100 of the flowchart shown in FIG. 2 written therein as a part of the program, and has the data table DTBL shown in FIG. 3, for example.

That is, this table DTBL is a set of data DFR indicating a frequency band, data DMD indicating a general reception mode in the frequency band, and data DBW indicating a general bandwidth in the frequency band. , And has the set for each frequency band.

For example, as shown in the column, for the medium wave broadcasting band, the data DFR indicating the frequency band 531 kHz to 1602 kHz, the data DMD indicating that the receiving mode is DSB, and the bandwidth thereof. Has a data bandwidth DBW indicating that the frequency band is 1603 kHz to the next frequency band, as shown in the column.
Data DFR indicating 2249 kHz and its reception mode is USB
And data DBW indicating that the bandwidth thereof is a narrow band.

Further, the RAM 54 stores the preset frequency data of the broadcasting station and the last channel (previously,
This is a memory for holding data such as the frequency received when the power was turned off, even when the power was turned off.
Therefore, the RAM 54 is a non-volatile memory capable of electrically erasing and writing data, or a memory backed up by a battery.

Further, 61 to 63 are output ports, and these ports 61 to 63 are also connected to the bus 59.
The frequency division ratio N is output from and set in the frequency division circuit 22,
The data D32 is output from the port 62 and supplied to the D / A converter 32.

Further, from the port 63 to the switch circuits 47-
These control signals are supplied to the switch circuit 49 and the switch circuit 47.
Is connected to the intermediate frequency amplifier 16W side when the bandwidth is wide, and is connected to the intermediate frequency amplifier 16N side when the bandwidth is narrow. Further, the switch circuit 48 is connected to the detection circuit 17 side when the reception mode is the DSB reception mode,
In the USB reception mode and the LSB reception mode, the mixer circuit 43 is connected. In addition, the switch circuit 49
When the reception mode is the USB reception mode, it is connected to the BFO 41 side, and when it is the LSB reception mode, it is connected to the BFO 42 side.

Further, 64 is an LCD controller and 65
Is an LCD, and the display on the LCD 65 is the controller 64
Through the control of the CPU 51, the reception frequency, reception mode, bandwidth, etc. are displayed.

Further, 66 is a key interface circuit, and through this interface circuit 66, the function key KFC, the registration key KRG, the tuning keys K01 to K05,
The numeric keypad KTE is connected to the bus 59. Although the functions of these keys KFC to KTE will be described later, each of these keys KFC to KTE is composed of a non-lock type push switch.

<< Tuning with Ten Key >> By operating the ten key KTE, the desired reception frequency f11 can be directly input to select a channel.

That is, a numeral indicating the frequency f11 desired to be received is input from the ten keys KTE. For example, if you want to receive 1242 kHz, you can use the numeric keypad KTE "1, 2, 4, 2".
Press the keys in order, and then press the “EXE” key on the numeric keypad KTE.

Then, the processing of the CPU 51 is the routine 1
Start from step 101 of 00, then step 1
In 02, by referring to the data table DTBL, the reception mode data DMD and the bandwidth data DBW for the frequency input from the ten-key KTE are extracted. In this case, since "1242" has been input, the data DMD indicating that the reception mode is DSB is entered from the column,
The data DBW indicating that the bandwidth is wide is fetched.

Subsequently, the processing of the CPU 51 is performed in step 10.
3 and proceeds to step 10 in this step 103.
Data DMD and D retrieved from the data table DTBL in 2
The switch circuits 47 to 49 are switched according to BW. In this case, the switch circuits 47 to 49 are switched to the states shown in the figure corresponding to the data DMD and DBW in the column.

Next, the processing of the CPU 51 proceeds to step 104, where the frequency input from the numeric keypad KTE is converted into a frequency division ratio N and data D32 for selecting the frequency, and then step 105
In step 104, the dividing ratio N and the data D32 converted in step 104 are supplied to the frequency dividing circuit 22 and the D / A converter 32, and then, in step 106, this routine 100 ends.

Therefore, in step 105, the reception frequency f11 becomes the frequency of the numerical value input from the ten key KTE. Further, at this time, in step 103, the intermediate frequency amplifier 16W or 16N is selected corresponding to the reception frequency f11 to have a bandwidth suitable for the reception frequency f11, and the reception mode is the DSB reception mode.
The USB reception mode or the LSB reception mode is set.
In this case, the intermediate frequency amplifier 16W is selected to have a wide bandwidth corresponding to the data DMD and DBW in the column, and the detection circuit 17 is selected to perform general AM detection.

In this way, when the reception frequency f11 is designated by the ten-key KTE, the frequency f11 is selected, and the reception mode and bandwidth corresponding to the frequency f11 are set according to the data DFR to DBW of the data table DTBL. ..

At this time, although not shown, the data of the reception frequency f11, the reception mode and the bandwidth are LC
It is supplied to the D controller 64, and the LCD 65 displays the reception frequency f11, the reception mode, and the bandwidth, for example,
Displayed as "1242 kHz", "AM", and "WIDE". Alternatively, if the reception frequency f11 is 1603 kHz, "1603 kHz", "USB" and "NARRO"
W ”is displayed.

Further, the numerical value indicating the reception frequency f11 at this time is written in the predetermined address A00 of the RAM 54 as the last channel data.

<Scan Reception> Since the structure for scan reception is the same as the conventional one, it is not shown in FIG. 1. However, when the scan reception key is pressed, the frequency division ratio N and the data D32 are input.
Changes with a predetermined magnitude, and this change causes the reception frequency f
11 changes with a predetermined frequency step.

When a broadcast wave signal or the like is received at a certain reception frequency f11, an intermediate frequency signal S15 is obtained. Therefore, the detection signal of this signal S15 informs the microcomputer 50 that the signal has been received. Scanning is stopped.

At this time, the routine 100 is executed so that the reception mode and the bandwidth correspond to the reception frequency f11 at that time. Further, the last channel data is stored in the RAM 54.

<< Frequency Preset >> Arbitrary frequency f11
When the channel selection key Ki (i = 0. 1 to 05) is pressed while the registration key KRG is being pressed, the numerical value indicating the reception frequency f11 at this time is stored in the RAM 54.
It is written in the address Ai corresponding to the selected tuning key Ki.

Therefore, the frequency f11 desired to be preset is
If the channel selection key Ki is pressed while pressing the registration key KRG, the received frequency f11 at that time is preset in the selected channel selection key Ki.

Then, this preset frequency f11
Can be tuned in with a single touch by selecting the following «Tuning with a tuning key».

<< Tuning by tuning key >> When the reception frequency f11 is preset in the tuning key Ki, the tuning key K
When i is pressed, data indicating the frequency f11 written in the address Ai corresponding to the pressed key Ki in the RAM 54 is read out, and then the routine 100 is executed.

Therefore, in the same manner as in the case of << tuning with the ten keys >>, the frequency f11 registered in the tuning key Ki is selected, and the frequency f11 is selected according to the result obtained by referring to the data table DTBL. The receiving mode and bandwidth are correspondingly selected. Further, the last channel data is stored in the RAM 54.

Therefore, when the tuning key Ki is pressed, the frequency f11 registered in the key Ki is selected, and the reception mode and bandwidth corresponding to the frequency f11 are set, and the frequency f11 of the frequency f11 is set. Reception is performed.

<< When the power is turned on >> When the power is turned on, the address A of the last channel of the RAM 54 is
Data indicating the frequency f11 of the last channel is read from 00, and then the routine 100 is executed.

Therefore, in the same manner as in the case of << tuning with a numeric keypad >>, the frequency f11 that was received when the power was turned off last time is selected, and the data table
According to the result of referring to the DTBL, the reception mode and the bandwidth are selected corresponding to the frequency f11.

Therefore, when the power is turned on from off, the frequency f received when the power was last turned off is changed.
When 11 is selected, the reception mode and bandwidth corresponding to the frequency f11 are set, and the reception of the frequency f11 is performed.

<Changing the reception mode> For example, when receiving the broadcast or communication of the DSB signal, the CPU 5
1 refers to the data table DTBL in the routine 100, the detection circuit 17 is selected, and the reception mode is set to the DSB reception mode.

However, if there is another radio wave within the band of the USB component or the LSB component of the DSB signal, beat failure may occur. In such a case, even in the case of the DSB signal, if the USB reception mode or the LSB reception mode is set, beat troubles are improved and the intended broadcast or communication becomes easy to hear.

"Changing reception mode" in this section is used in such a case, and the data table DT
The reception mode set in BL is when reception is performed in a different reception mode.

That is, when the function key KFU is pressed while receiving the arbitrary frequency f11, the key flag is set, and thereafter, for example, the first channel selection key K01 functions as a change key for the reception mode. ..

Therefore, each time the key K01 is pressed, the switch circuits 48 and 49 are switched in a predetermined order each time the key K01 is pressed, and the reception mode is cyclic between the DSB reception mode, the USB reception mode and the LSB reception mode. Switch to.

Therefore, by the above key operation, the broadcast signal currently being received can be received in a reception mode different from the reception mode set in the data table DTBL.

When the function key KFU is pressed again, the key flag is reset regardless of the reception mode at that time, and thereafter, the key K01 is the original key as described in << Tuning by the tuning key >>. It will act as a tuning key.

Even if the reception mode is changed in this way, when the next tuning operation is performed, even if the reception frequency f11 after tuning is the same as that before tuning, the data table DTBL
Is referred to, the function key KFU and the key K
The reception mode set by 01 is canceled.

<< Change of Bandwidth >> For example, when a medium-wave broadcast is being received, the CPU 51 refers to the data table DTBL in the routine 100 to select the intermediate frequency amplifier 16W, and the bandwidth is wide. Is set to.

However, if there is another broadcast wave in the vicinity of the DSB signal, interference may occur. Then, in such a case, if the intermediate frequency amplifier 16N is selected and the bandwidth is set to a narrow band, interference is improved and the intended broadcast or communication becomes easier to hear.

The "change of bandwidth" in this section is used in such a case, and it is a case where reception is performed with a bandwidth different from the bandwidth set in the data table DTBL.

That is, when the function key KFU is pressed while receiving an arbitrary frequency f11, the key flag is set, and thereafter, for example, the second tuning key K02 acts as a bandwidth changing key. ..

Therefore, each time the key K02 is pressed, the switch circuit 47 is switched each time the key K02 is pressed, and the bandwidth is alternately switched between the wide band and the narrow band.

Therefore, by this key operation, the broadcast signal currently being received can be received with a bandwidth different from the bandwidth set in the data table DTBL.

When the function key KFU is pressed again, the key flag is reset regardless of the bandwidth at that time, and thereafter, the key K02 is the original key as described in "Tuning with the tuning key" above. It will act as a tuning key.

Even if the bandwidth is changed in this way, the next time the tuning operation is performed, the data table DTBL is referenced even if the reception frequency f11 after tuning is the same as that before tuning. Therefore, the bandwidth set by the function keys KFU and K02 is canceled.

<< Others >> In the above description, the data table DTBL of FIG. 3 is prepared in the ROM 52.
This can be prepared in the RAM 54. Also, RA
When prepared in M54, the setting of the reception mode or bandwidth can be changed.

In the above description, the intermediate frequency amplifiers 16W and 16N are selected according to the bandwidth, but a wide band intermediate frequency filter and a narrow band intermediate frequency filter are selected according to the bandwidth. The selected output may be supplied to the amplifier.

[0083]

According to the present invention, for each reception band,
Paying attention to the fact that the reception mode and bandwidth are almost fixed, if the reception frequency f11 is input, the data table DT
By referring to BL, the reception mode and bandwidth are automatically set in correspondence with the reception frequency f11.

Therefore, when receiving medium-wave broadcasting, short-wave broadcasting, or short-wave communication, the receiving mode is switched to the DSB receiving mode, the USB receiving mode, or the LSB receiving mode by the manual operation according to the transmission signal, It is not necessary to switch the bandwidth of the frequency amplifier according to the bandwidth of the transmission signal, the receiving operation is easy, and even those who are not able to do shortwave broadcasting,
You can easily receive various broadcasts and communications.

Also, during scan reception,
Since the reception mode and bandwidth are automatically switched according to the reception frequency, the merit of scan reception can be fully utilized.

Moreover, the data table DTBL is stored in the ROM 52.
Since it is only necessary to prepare the routine 100 and the routine 100, the cost is low.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of the present invention.

FIG. 2 is a flowchart showing an example of a tuning routine.

FIG. 3 is a diagram showing an example of a data table.

[Explanation of symbols]

 13 1st mixer circuit 14 1st intermediate frequency amplifier 15 2nd mixer circuit 16 2nd intermediate frequency amplifier 17 AM detection circuit 20 PLL 21 VCO 22 Variable frequency divider circuit 31 VCXO 32 D / A converter 41 USB BFO 42 For LSB BFO 43 Mixer circuit 50 Microcomputer 100 Tuning routine KFC to KTE operation keys

Claims (1)

[Claims] 1. A data table having a set of data corresponding to a receiving frequency, data of a receiving mode for the receiving frequency, and data of a bandwidth for the receiving frequency, when setting the receiving frequency, or When set, the data table is referred to, the data of the reception mode and the data of the bandwidth, which is paired with the set or set reception frequency, is retrieved from the data table, and the retrieved reception is performed. A super-heterodyne receiver configured to set a reception mode and bandwidth according to mode data and the bandwidth data.