JP3055052B2 - Automatic frequency adjustment method for wireless communication equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication apparatus for automatically adjusting local oscillation frequencies for transmission and reception in order to set desired transmission and reception frequencies in telecommunications of A1 type. The present invention relates to an automatic frequency adjustment method.

[0002]

2. Description of the Related Art Telegraph communication is a method in which a carrier (hereinafter, referred to as a carrier) is intermittently operated mainly by a key operation, and the radio wave type is an A1 type. In the A1 type telegraphic communication, a radio wave is emitted when the electronic key is in "contact", and the radio wave is amplitude-modulated on the carrier at a modulation factor of 100%.

In order to receive an A1 type radio wave and listen to a telegraph code, a demodulator provided in the receiver uses an intermediate frequency of the received radio wave and a beat oscillator (hereinafter referred to as BF) provided in the receiver.
Called O. A heterodyne beat is formed with the oscillation frequency of ()), and it is heard as a telegraph code. Generally, the BFO is set so that the demodulation frequency of the telegraph code is 300 Hz to 900 Hz.
(Hereinafter referred to as BFO frequency) is set.

Conventionally, in the reception of A1 type radio waves performed by an operator, the BFO frequency is set and the reception frequency is adjusted while listening to the demodulated signal. If the frequency of the demodulated signal (hereinafter, referred to as demodulated frequency) sounds different from the desired demodulated frequency set by the BFO, it is determined that the reception frequency is detuned.

Therefore, in order to accurately adjust the reception frequency, a tone oscillator capable of oscillating the same frequency as the demodulated signal is separately used in the receiver, the tone signal is superimposed on the demodulated signal, and the growl generated at that time is reduced. The operator measured the degree of detuning, and the operator adjusted the receiving frequency with the point at which the groan became the minimum as the tuning point.

However, since the demodulated signal of telecommunications is intermittent, the above-mentioned hum is also heard intermittently, and it is not easy to adjust the reception frequency. Also, in telegraphic communication using the normal A1 type, the calling station is in a reception standby state at the same frequency as the frequency transmitted by its own station after the end of the calling. It is necessary to completely match the transmission frequency of the own station with the reception frequency of the other party. Therefore, the transmission frequency in the A1 type telegraphic communication becomes the same as the reception frequency at the time of reception, so that the detuning of the reception frequency is directly the detuning of the transmission frequency. As a result, the difference between the reception frequency and the transmission frequency directly causes distortion of the demodulated signal.

[0007] Further, since the A1 type telegraph communication is mainly operated in the HF band, the frequency of transmission and reception changes with time even if tuning is performed once. Therefore, the operator constantly monitors the reception frequency. Adjustments need to be made.

The above-described conventional method of adjusting the reception frequency in the A1 type telegraph communication relies on the hearing of the operator to adjust the reception frequency, and individual variations occur. In some cases, the receiving frequency was detuned. As described above, the adjustment of the receiving frequency in the A1 type telegraph communication requires experience and the like, and it is generally said that even if a skilled operator carefully operates, the accuracy of the tuning is around 30 Hz. .

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to automatically tune the reception frequency and oscillate the transmission frequency accurately. In addition, by introducing the present invention to telecommunications, stable telegraphic communication can be performed.

[0010]

Means for Solving the Problems In order to achieve the above object, the present invention relates to a radio communication device having a telecommunication function, wherein a demodulation circuit intermittently responds to a telegraph code.
A detection circuit for detecting a carrier signal output to the
A waveform shaping circuit for pulsing a transmission signal, and the detection circuit
Gates at a fixed cycle based on the point at which the
Open and close, and only when the gate is open from the waveform shaping circuit
A gate circuit for outputting the obtained pulse, and the gate
Counter circuit that counts the number of pulses output by the circuit
And the count number of the counter circuit within a predetermined time
And the opening time of the gate circuit within the predetermined time
And the frequency of the carrier signal from the count number
A data processing circuit is provided for
The detuning state of the reception frequency is determined from the difference from the frequency obtained by the data processing circuit, and a control signal corresponding to the detuning state is output to the local oscillator to automatically adjust the local oscillation frequency to thereby adjust the reception frequency. Provided is an automatic frequency adjustment method for a wireless communication device, which is characterized by eliminating a detuning state .

[0011]

The conventional transmission / reception frequency conversion section of a wireless communication device in telecommunications has no function of monitoring the detuning state of the transmission / reception frequency. There was no means to adjust except to adjust.

[0012] automatic frequency adjustment method of the radio communication apparatus of the present invention, Oite the telegraphic communications, corresponds to the telegraph code from the demodulation circuit
Measure the frequency of the intermittently output carrier signal ,
It is taken into a microcomputer or the like, and the local oscillation frequency is controlled again to automatically eliminate the detuning state of the transmission / reception frequency. According to the present invention, the reception frequency is adjusted so as to be automatically tuned in time, and the correct transmission frequency is oscillated,
Stable telecommunications can be realized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of an apparatus that counts and measures an A1 type reception frequency, corrects PLL data, controls a local oscillation frequency again, and automatically eliminates a detuning state of a transmission / reception frequency. In the figure, 1 is a counting circuit (hereinafter referred to as COUNT), 2 is a gate circuit (hereinafter referred to as GATE), 3 is a waveform shaping circuit (hereinafter referred to as PULSE), 4 is a variable band-limited filter, Is a BFO circuit, 6 is a frequency converter (hereinafter, MIX)
(A). ), 7 are low-pass filters (hereinafter, LPF)
(A). ), 8 is a low frequency amplifier, 9 is a filter, 1
0 is a detection circuit, 11 is a microcomputer (hereinafter C)
It is called PU. ) And 12 are PLL circuits, 13 is a local oscillator for reception (hereinafter referred to as VCO (RX)), 14 is a local oscillator for transmission (hereinafter referred to as VCO (TX)), and 15.
Is a frequency converter (hereinafter referred to as MIX (b)), 16
Is a band-limited filter, 17 is an intermediate-frequency amplifier, 18 is a low-pass filter (hereinafter referred to as LPF (b)), 19 is a low-frequency amplifier, 20 is a speaker, 21 is a reception frequency, 22 is an intermediate frequency, and 23 Is the demodulation frequency, 24 is the BFO frequency, 2
5 is a local oscillation frequency at reception (hereinafter referred to as fLR), 2
6 is a local oscillation frequency during transmission (hereinafter referred to as fLT);
7 is a VCO (RX) control signal, 28 is a VCO (TX) control signal, 29 is count value data, 30 is a BFO control signal,
31 is a PLL control signal, 32 is a carrier detection signal, 33
Is a gate control signal, 34 is a BPF control signal, 35 is an intermediate frequency circuit (hereinafter referred to as IF CIRCUIT), 3
6 is a demodulation circuit (hereinafter, DEMODULATE CIRC)
It is called UIT. ) And 37 are counting circuits (hereinafter referred to as COUNT).
ER CIRCUIT. ), 38 are filter circuits (hereinafter referred to as FILTER CIRCUIT), 3
9 is a local oscillation circuit (hereinafter, PLL / VCO CIRCU)
IT. ) And 40 are arithmetic circuits (hereinafter referred to as CPU CI).
RCUIT. ) And 41 are audio circuits (hereinafter, referred to as audio circuits).
AUDIO CIRCUIT. ) And 42 are frequency discrimination circuits.

FIG. 2 is a waveform diagram showing the operation of a counting circuit and the like when counting and measuring, where P (1) to P (3) are count data, tg is a delay time, τ is a gate open time, r Is the gate closing time, and m is the measurement time. “Carrier” shown in (1) of FIG. 2 is a received signal and indicates “N” of a Morse code. This Morse code is composed of a long point, a space, and a short point, and the short point and the space have the same length. And the pros are 3
Doubled. "Carrier detected?" Shown in (2) of FIG. 2 indicates the signal state of the carrier detection signal 32 of FIG. 1, and indicates the detection state when the carrier detection circuit 10 detects a carrier to the microcomputer 11. Indicates a change. "Carrier waveform shaping" shown in (3) of FIG.
5 shows a state in which the sine wave of the demodulated signal is pulsed by the waveform shaping circuit 3 in FIG. The “gate” shown in (4) of FIG.
2 shows an operation example of the gate circuit 2 of FIG. “CountΣs” shown in (5) of FIG. 2 is a state where the counting is performed by the counting circuit 1 of FIG. Hereinafter, description will be made based on the Morse code shown in (1) of FIG.

FIG. 3 is a flowchart showing the operation of the counting circuit and the like when counting and measuring.
Initialization process, S2 processing delay time tg, S 3 is the gate opening processing, S 4 the process of counting up? S, S 5 is the gate closing process, S 6 is DATA processing, S 7 the processing of PLL correction , S 8 the gate closing process, S 9 data processing count value, H1 determination of carrier detection, H2 determination of gate open time, H3 determination of carrier detection, H4 determination of the measurement time, H5 is H6 is the determination of carrier detection, and H6 is the determination of gate closing time.

An operator sets a desired reception frequency and a BFO frequency (hereinafter, referred to as fBFO) for the superheterodyne wireless communication apparatus of the automatic frequency adjustment system of the present invention, and sets a delay time according to the present invention. Set the measurement time, gate opening time and gate closing time.

As described above, when various settings are received and the Morse code shown in FIG. 2A is received at the detuned reception frequency, the transmission and reception frequency is automatically adjusted by the automatic frequency adjustment method of the present invention. The process will be described below.

The detuned reception frequency (hereinafter, referred to as f'RF) is a desired reception frequency (hereinafter, referred to as fRF) and a detuning frequency (hereinafter, referred to as Δf) as shown in equation (1). And the relationship. f′RF = fRF + Δf (1)

In IF CIRCUIT 35, f '
The RF is mixed with the fLR 25 in the MIX (a) 15 and frequency-converted, and then becomes a detuned intermediate frequency (hereinafter referred to as f′IF). As shown in equation (2), f′IF is in a state where the frequency is detuned by Δf from a desired intermediate frequency (hereinafter, referred to as fIF). f′IF = | (fRF + Δf) −fLR | = fIF + Δf (∵fIF = | fRF−fLR |) (2) Thereafter, f′IF is a band of the harmonic component of f′IF generated by the frequency conversion. The signal is filtered by the limiting filter 16 and amplified by the intermediate frequency amplifier 17.

DEMODULATE CIRCUIT3
At 6, the fBFO 24 is output from the BFO circuit 5 using the BFO control signal 30. f'IF is MIX
(B) The signal is mixed with the fBFO input to 6 and frequency-converted to output a demodulated signal. As shown in equation (3), the demodulated signal is obtained by subtracting Δ from a desired demodulation frequency (hereinafter, referred to as fAF).
It can be seen that the demodulated frequency is detuned by f (hereinafter, referred to as f'AF). f′AF = | f′IF−fBFO | = | (fIF + Δf) −fBFO | = fAF + Δf (∵fAF = | fIF−fBFO |) (3) Then, the demodulated signal is frequency-converted by the low-pass filter 7. AUDIOCIR is used to remove harmonics generated at that time, amplify the signal in the low-frequency amplifier 8 and convert it into audio as a telegraph code.
It is input to the CUIT 41 and is also input to the FILTER CIRCUIT 38 for setting a measurement range and detecting a carrier.

In the AUDIO CIRCUIT 41, the f'AF is low-pass filtered by the LPF (b) 18 and is driven from the low-frequency amplifier 19 to the speaker 20, so that the voiced telegraph code can be heard. According to equation (3), the voiced telegraph code heard from the speaker 20 is detuned by Δf from the frequency of the desired telegraph code.

The pass band of the variable band-pass filter 4 in the FILTER CIRCUIT 38 becomes a measurement range of the count measurement, and eliminates unnecessary signals from the demodulated signal. The center frequency (hereinafter referred to as fBPF) of the variable band-pass filter 4 is set by using the BPF control signal 34 from the CPU 11.

The fBPF is set by detecting the demodulated signal with a plurality of filters of the frequency discriminating circuit group 42 and detecting it by the detecting circuit, and transmitting the result as detection data to the CPU 11 via the carrier detecting signal 32. . The CPU 11 performs desired data processing based on the sent detection data and calculates a set value of fBPF.

In the COUNTER CIRCUIT 37, the demodulated signal is pulsed, and the number of pulses within a predetermined time is counted. The pulse counting measurement is mainly performed by the waveform shaping circuit 3, the gate circuit 2, and the counting circuit 1.

The waveform shaping circuit 3 is a circuit for converting a sine wave into a pulse, and mainly includes a Schmitt trigger circuit and a differentiating circuit. The Schmitt trigger circuit has a characteristic of converting any input signal into a square wave and outputting the square wave. The square wave is passed through a differentiating circuit and output as a pulse corresponding to the frequency of the input signal.

Therefore, f'AF having Morse code as shown in (1) of FIG. 2 is input to the Schmitt trigger circuit, becomes a square wave, and passes through the differentiating circuit.
The pulse is output as shown in (3).

The gate circuit 2 has a gate control signal 33
Then, the gate is opened / closed in a preset operation cycle, a pulse is passed for a predetermined time, and a pulse is supplied to the counting circuit 1 in the next stage.

The counting circuit 1 counts up the number of given pulses and supplies the counted number as pulse count data 29 to the microcomputer 11. As shown by equation (3), f ′
Since AF is composed of fAF and Δf, count value data (hereinafter, Σ) when f′AF is pulsed and counted up.
It is called s'. ) Is composed of count value data of fAF (hereinafter, referred to as Σs) and count value data of Δf (hereinafter, ΣΔs), as shown in Expression (4). Σs ′ = Σs + ΣΔs (4)

The presence or absence of a received signal in carrier detection will be described below. The intermediate frequency at the time of no signal in the heterodyne reception becomes equal to the local oscillation frequency because the reception frequency is zero.Therefore, the intermediate frequency at the time of no signal is reduced by the narrow-band band-limiting filter 16 in front of the demodulator. It is not filtered and input to the demodulator. Therefore, the demodulation frequency at the time of no signal becomes equal to the BFO frequency because the intermediate frequency becomes zero.

Generally, the demodulation frequency of the A1 type is 700H
z, and the BFO frequency at this time is 455.7 kHz.
Since it is z, the demodulation frequency when there is no signal when the demodulation frequency is 700 Hz is 455.7, which is equal to the BFO frequency.
kHz.

Therefore, the demodulation frequency of A1 type 700 Hz
And the demodulation frequency of 455.7 kHz when there is no signal is 651 octaves, and the carrier detection indicating the presence or absence of the received signal can be sufficiently determined from the state of these two frequencies.

The carrier detection signal is represented by (1) in FIG.
, That is, “Yes” for a long dot, “No” for a space, and “Yes” for a short dot. Then, this signal state is output to the CPU 11.

A process until the PLL data to be counted and measured is corrected will be described with reference to the flowchart in FIG. Sets the range and total measuring conditions in as S 2 shown in the above counting measurement, the determination of the carrier detection in H1. S 2
In consideration of the delay time from when the f'AF is amplified, band-limited and pulsed, the processing waits for an arbitrarily set delay time tg before the gate is opened. Open S 3 in the gate, a pulse in H2 passed through only the gate open time tau,
In S 4, which is counted up, including pulses of Delta] f.

After counting in S 4 , the presence or absence of a carrier is determined by detecting the carrier of H 3. At that time, if there is no carrier, the flow proceeds to S 5 , and if there is a carrier, the flow returns to H 2 and the flow returns to H 2 within the gate opening time. again counts the number S 4 if Re, the process proceeds to S 8 as long past the gate open time τ. S 5 and S 8 is a process of closing the gate. After closing the gate at S 8, data of the count value up to that point in S 9. After that, carrier detection is performed again at H5, and if there is no carrier, H is detected.
Then, if there is a carrier, the process waits for the gate closing time r at H6. During this standby, the presence or absence of the carrier is constantly monitored with H5. After the gate closed between r waiting, opened the gate to return to the S 3 again.

[0035] In addition, the fact that the gate closes S 5 is, but is within the gate opening hours, since it is the fact that the carrier has disappeared, there is no reliability of the count value has been counted up in S 4 up to it Therefore, the count value is not converted to data and the process proceeds to H4.

At H4, it is determined whether or not it is within the measurement time, and if it is within the time, the flow returns to H1 and measurement is performed again. If the measured time m has been completed subjected to data processing in the count value data P that is data reduction in S 9 proceeds to S 6 (n), P indicated by S 7
The LL data is corrected.

In conjunction with the above description of the flowchart of FIG. 3, the counting and measurement of the Morse code shown in FIG. 2A will be described with reference to FIG. After the first point of the Morse code shown in (1) of FIG.
After g, the gate is opened. First, the count value data counted up during the gate opening time τ is defined as P (1).

Next, when the gate is opened, there is still a carrier, so after the gate closing time r hours, the gate is opened again,
Again, the count value data counted up during the gate opening time τ is set to P (2).

Since there is still a carrier, the gate opens again after the gate closing time r, and counts up during the gate opening time τ. However, the carrier runs out during the gate opening time τ, so the counting was increased. Count data is P
(3) instead of Perror and the gate is closed.

Since the measurement time is still within the measurement time, when the short point is detected again, the gate is opened for the gate open time τ and counted up after waiting for the processing for the delay time tg. The count value data at this time is defined as P (3). Then, the gate is closed for the inter-gate time r, and the gate is opened again if there is a carrier. However, since the carrier has disappeared and the measurement time m has passed, the counting measurement is completed, and the next obtained count value data P ( 1) to P (3) are performed, and the PLL data is corrected.

CPU CPU1 of CIRCUIT40
In step 1, data processing is performed using the count value data P (1), P (2) and P (3), and PLL data correction processing is performed.
New PLL / VCO CIRC with PLL control signal 31
It controls the PLL circuit 12 of the UIT 39. In particular,
The number of pulses added with the count value data and the gate circuit 2 open
From the set total time, the frequency of the carrier (carrier) signal
Number and determine its frequency and the desired reception
Finds the difference from the frequency and the PLL system corresponding to the frequency difference
The control signal 31 is created. From the PLL circuit 12 to the local oscillation circuit 13 for reception and the local oscillation circuit 14 for transmission, a new V
CO (RX) control signal 27 and VCO (TX) control signal 2
8 is transmitted, the receiving local oscillation circuit 13 newly outputs the receiving local oscillation frequency 25 shown by the equation (5), and the transmitting local oscillation circuit 14 sends the transmitting local oscillation frequency 26 shown by the equation (6). Is newly output. fLR = fLR + Δf (5) fLT = fLT + Δf (6)

As described above, in the IF CIRCUIT 35, the frequency of the detuned reception frequency f'RF is converted again by the newly output local oscillation frequency 25 at the time of reception shown in the expression (5), and the expression (2) and the expression As shown by the calculation of the equation (7) from the equation (5), the detuned intermediate frequency f′IF becomes equal to the desired intermediate frequency fIF, and the DEMODULATE CIRC
It is supplied to the UIT 36. f′IF = | (fRF + Δf) −fLR | = | (fRF + Δf) − (fLR + Δf) | = | fRF−fLR | = fIF (7)

Thereafter, the DEMODULATE CIRC
In the UIT 36, the f'IF equal to the desired intermediate frequency is mixed with fBFO in the MIX (b), and the equation (3)
As shown by the calculation of Expression (7) to Expression (8), the detuned demodulation frequency f'AF becomes equal to the desired demodulation frequency fAF. f'AF = | f'IF-fBFO | = | fIF-fBFO | = fAF (8)

Accordingly, the detuning frequency disappears from the demodulation frequency, and the detuning state of the reception frequency is eliminated, and the detuning state of the transmission frequency is also eliminated. While the automatic frequency adjustment method of the present invention is operating, the demodulation frequency in telecommunications is constantly monitored, the local oscillation frequency is readjusted to eliminate the detuned state of the transmission / reception frequency, and the transmission / reception frequency is always tuned. ing.

In this embodiment, in the data processing, the deviation of the frequency detuning is directly calculated as the correction value of the PLL data. However, when the transmission / reception frequency changes irregularly, the above-mentioned data processing is performed. We cannot respond appropriately. Therefore, in addition to the above-described data processing, statistically considering the count value data as a random variable, for example, deriving an autocorrelation function from the acquired data, correcting the PLL data according to a temporal change, or Even if the transmission / reception frequency changes irregularly by changing the data processing in various ways, such as performing a fuzzy control on the correction of the PLL data by deriving the membership function from the acquired data, it is suitable for the operator's orientation. PLL data can be corrected.

The function of adjusting the detuning of the transmission / reception frequency as described above can be variously modified based on the operation described in the present embodiment.

The present invention can be applied to various radio wave types other than the A1 type by extracting or reproducing carriers and returning to the embodiments of the present invention.

[0048]

As described above, the frequency detuning has been large in conventional cases where manual reception is not possible at all times, or when an automatically received telegraph is recorded and used later. Even if the quality of the signal deteriorates, it was necessary to listen as it was, but in telegraph communication using the automatic frequency adjustment method of the present invention, without the operator constantly worrying about the state of the reception frequency, Telegraph communication with a stable transmission / reception frequency can be realized, the transmission / reception frequency is automatically stabilized, and the reliability of the radio system is improved. Further, according to the present invention, since the reception frequency is automatically tuned by telecommunication, the present invention can be widely used not only for telecommunication between fixed stations but also for mobile radio and fishery radio.

In view of the recent development of microcomputer technology and the like, various data processing and signal processing are also performed at a high speed, so that the response of the automatic frequency adjustment of the present invention is considered to be extremely fast. The automatic frequency adjustment method of the present invention has an extremely excellent effect in telecommunications of a wireless communication device.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a waveform diagram of one embodiment of the present invention.

FIG. 3 is a flowchart of one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Counting circuit 13 Local oscillator for reception 2 Gate circuit 21 Receiving frequency 3 Waveform shaping circuit 22 Intermediate frequency 4 Variable band limiting filter 23 Demodulation frequency 5 BFO circuit 24 BFO
Frequency 6 Frequency converter 25 Local oscillation frequency at reception 7 Low-pass filter 29 Count data 8 Low-frequency amplifier 30 BFO
Control signal 9 Filter 31 PLL
Control signal 10 Detection circuit 32 Carrier detection signal 11 Microcomputer 33 Gate control signal 12 PLL circuit 34 BP
F control signal τ Gate opening time tg Delay time m Measurement time r Gate closing time S9 Count data conversion P (1) to P (3) Count data

Claims (1)

(57) [Claims] In a wireless communication device having a telecommunication function, a demodulation circuit intermittently outputs a signal corresponding to a telegraph code.
A detection circuit for detecting a carrier signal to be detected, and the carrier signal
A waveform shaping circuit for pulsing the signal, and the detecting circuit
Gates open and close at regular intervals based on signal detection
And only when the gate is open is obtained from the waveform shaping circuit.
And a gate circuit for outputting a pulse.
A counter circuit for counting the number of pulses to be output;
Count the number of counts of the counter circuit in time
And the opening time of the gate circuit within the predetermined time and the
Data for obtaining the frequency of the carrier signal from the count number
Provided data processing circuit, wherein the desired frequency a preset de
Automatically determine the detuning state of the received frequency from the difference from the frequency obtained by the data processing circuit, and output a control signal corresponding to the detuning state to the local oscillator to automatically adjust the local oscillation frequency.
Characterized in that to eliminate the detuning state of the reception frequency by
Automatic frequency adjustment method of a radio communication device has.