JPS6039928A - Radio receiver - Google Patents

Abstract

PURPOSE:To improve the talking quality and to distinguish easily the start and end of talking by performing muting with a frame synchronizing signal of a control signal and also replacing respectively the control signal of the start and end to a high and a low tone burst. CONSTITUTION:A detecting means 82 detects a wave to be modulated for a voice siganl and the control signal, outputs the result to a muting circuit 86 and an output of the circuit 86 is fed to a voice signal circuit 84. Further, a control signal detecting means 4 detects the control signal from the output of the menas 82, a means 30 generates a muting pulse and gives it to the circuit 86 via an output port 31. On the other hand, the means 30 supplies the tone burst to the circuit 84 via an output port 32 and an adder circuit 87.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a radio receiver suitable for personal radio systems. Many radio devices for personal radios have already appeared on the market. First, an overview of personal radio systems is as follows.

1) Usage frequency 903~! 105MIlz, 80 channels 2) Output 5W 3) Radio wave type FM 4) Automatic line connection method 5) Selective call using 5-digit group number 6) Automatic identification code sending method (8uLomatic Tr
ansmitterIdentification S
system) Next, with reference to FIG. 1, a general configuration of a personal wireless radio device will be explained. In FIG. 1, (1) indicates a transmitter, and this transmitter (1) is
The mixer circuit receives the local oscillation signal from the frequency synthesizer (2) using a crystal oscillator, °ζ, 903.0125
MIIz control channel and 903.0375~
It is possible to transmit radio waves of 79 communication channels arranged at 25kllz intervals in the range of 904.9875MI+2. The radio wave type is F2 for the control channel and F3 for the communication channel (based on phase modulation). (3) indicates a microcomputer, and this microcomputer (3) uses a frequency synthesizer (2) for line connection, selective calling, automatic identification code transmission, etc.
and a modem (4). (5) indicates the microphone 215. The audio signal from the microbond (5) and the control data signal from the modulator/demodulator (4) are fed to the transmitter (1), and the modulated radio waves of a predetermined type from the transmitter (11) are transmitted to the transmitter (1). (J) is sent to the antenna (7) via the transmission/reception selector switch (6) and transmitted.

(8) indicates a receiving section, and this receiving section (8) receives the local oscillation signal from the frequency synthesizer (2) with a mixer circuit, and receives the above-mentioned control channel and 79 calls transmitted from other radios. channels can be received.

The audio output of the receiving section (8) is supplied to the speaker (9),
The control data signal is supplied to a modem (4).

Next, please refer to Figure 2 regarding the control signals of the personal wireless system! I will explain it in 16 words. The control signals include a bit synchronization signal a and a frame synchronization signal arranged in sequence, as well as data (group code signal d for automatic line connection in H4i JIC, channel code signal e, command code signal f and 01' output name (ATIS). ) is a digital data signal consisting of @g, which is transmitted by F2 radio waves.

The bit synchronization signal a of 50 pins I, represented by 1101010...l0IOJ, is No. 18 for transmitting the clock timing of the computer of the transmitting side radio to the receiving side radio. In the machine, the timing at which the computer reads digital data is adjusted to this hit synchronization signal a to ensure subsequent reading of digital data. Next 1-11101100LO1,
The 15-bit I-frame synchronization signal represented by 0OOOj is used to notify the position of the target data in advance, and if the receiving side radio cannot accurately receive 14 bits or more of the I5 bits, the data- It is assumed that there is some kind of abnormality, and subsequent signal data is ignored.

On the other hand, after this frame synchronization signal, the data signal C is 17
2 pitsu 1 ~ continues.

The 21 code signal d for 20 pins I~ is a 5-digit number BC
It is a D-converted signal, and uses a preset group code signal for transmission or a group code signal called at the time of receiving a call.

This group code signal d is a code signal similar to a telephone number and is used to identify the user (self or other party) of the personal radio, and the user arbitrarily sets two group code signals. You can also do that. Furthermore, this group code signal d has a reception (when the control signal is received by the radio on the R side, the control signal d is the group code I set by itself in the number).
(Only if there is a No. g, the receiving radio is called.
The computer determines that you are there, and you can make a call.Jl'
lj:J-1'' It has a selective calling function that ignores the control signal if the m code does not match.

8-bit channel code signal This is a code signal obtained by converting the channel number to BCD.

The 4-hit command code signal f is preliminary and is currently r000J. 48-bit calling name (^TTS) signal [is an identification signal unique to the radio,
When obtaining a personal radio license, the radio equipment (zJ Gen-4-R
T to OM cartridge! ) to be included.

The total of the above four types of code signals d-g is 80 bits, but in order to correct bits errors caused by noise in the wireless line, the data signal C is processed using Berleelberger code. The result is a 172-bit data signal.

The above control signal has a transmission rate of 1200 bits/sec, a mark frequency of 120011z, and a space frequency of 180011
Synchronized using the FSK method of When the signal is continuous at zero crossing r1, the required frequency bandwidth is minimum, so minimum breath shift keying (formerly known as nimum SI
+ift Keyig).

Further, the operation of the personal radio will be explained with reference to the solo charts of FIGS. 3A and 3B.

When the power switch is turned on, the radio enters standby mode. In this state, the operator can call MIi+ himself.
Decide whether to make a call request, make a TA request to monitor and receive the communication channel, or just wait for an incoming call, and send an instruction to the radio. In this case, it is first necessary to set some group code using the radio's ten key settings.

(/l',) Calling operation Calling the radio ((:ALL) button or microphone press (Press to Ta1k)
Each time the switch (hereinafter referred to as the PTT switch) is pressed, an instruction is given to the radio to enter the start U=F operation.

In the calling operation, an empty channel is searched, the channel number is sent out on the control channel, and the other party is informed of the calling operation.The empty channel search is performed in the following procedure. Select any one channel from the call channels and receive that channel.

■ If there is a human input signal (including noise) of IttV or higher on that channel, another channel selected by default will be received.

(2) Repeat operation (2) until a channel where the input signal is less than 1 μV is searched, and when a channel where the input signal is less than 1 μV is searched, 1f11 of I sand amount: Continue reception.

■ If there is a human input signal of 1 μV or more within 1 second, ■
Return to operation.

If there is no human signal of 187 or higher, write down the channel number 1. α and return to the control channel.

(B) Waiting for incoming calls In this case, two group code signals for incoming calls can be set at the same time.

When the code of the group 2 node signal in the received control signal matches one of the two group codes you set, (
By setting the control signal), record the group 2 signal f1 and enter the capture operation.

(C) By pressing the reception request (MONI) button on the monitor operation radio,
5. Give instructions to the radio. After entering the monitor operation, you can select any one channel from 79 communication channels and receive the radio waves of that channel.

During monitor operation, if the code of the group code signal in the received control signal matches one of your two preset group codes, if you send a request within 5 minutes, the radio will operate for talking ( can enter.

(D) Acquisition operation Acquisition operation is mainly performed when ζ standby operation 11 Yuko receives a call.

In the case of a specific call, if there is an input signal of 187 or more on the call channel, the call operation reception state is automatically entered. In addition, 1 μ
If it is unable to receive a V or H signal, it is determined that the other party's selling has been discontinued, and automatically returns to standby mode (by timer operation).

If the setting group code is 1-00000 J, press the ball l-' (IIOL+1) button.
(It enters the receiving state for call operation, but it is held (IIOL)
D) When no button is pressed, the standby operation starts after 10 seconds regardless of the presence or absence of an input signal.

Note that if you press the PTT switch during the capture operation and miss the ``1 transmission request'', the device enters the transmission state of the call operation.

E) Call operation When the call operation is started from the optical ntit operation, the monitor operation, and the capture operation, it is possible to talk to the other party, and each time the call termination request (RESIET) button is pressed, the standby operation is returned.

In the transmission state of this call operation, the above-mentioned control signal is automatically sent out at the beginning of transmission, every minute during transmission, and at the end of transmission according to the previous 'Is.

In addition to the above-mentioned operations, there is also an i+j: "J' output operation in the operation of the personal radio, but its explanation is omitted.
Ru.

However, in personal wireless systems, as mentioned above,
During transmission, control signals as shown in Figure 2 are sent at the beginning and end, and every minute from the beginning of transmission.
The low-frequency output of the radio during reception includes call tone, 'fi(;=
There is a problem in that a control signal sound is mixed in with the i signal, reducing reception quality.

Now, with reference to FIGS. 4 and 5, we will examine the received sound of a conventional personal radio.

FIG. 4 shows part of a receiving system of a conventional personal radio. In this FIG. 4, (81) indicates an input terminal, from which the FM intermediate frequency signal is supplied to the FM detector (tis liminator) (82), and from the FM detector (82) The subcarrier control signal is supplied to the modulator (4), and the subcarrier control signal and phase modifier irl! The detection output of the d-wave is converted back into an audio signal by an integrating circuit (83) and supplied to a low frequency amplifier (84). (30) is microphone r:2 computer (7) CP
U wo; I”: し、このCP LJ (30) is connected to the converter (4). (85) indicates the squelch signal terminal, and no high-frequency human input signal is supplied to the receiver. In this case, the Skelna signal is supplied from the Skelna signal terminal (85) to the low frequency 1 (9-width amplifier (84)) to cut off the output supply to the speaker (9).

For the receiving i) yarn with the structure shown in Fig. 4, the rK
Then, the squelch is turned off and the audio output from the speaker (9) includes the first control signal sound A, as shown in Figure 5.
The call voice Va appears following s. One minute after the call is received, an intermediate control signal tone appears and the call continues.
), the voice vb appears. When the call ends, an end control signal tone appears.

When the transmission from the transmitting radio ends and the high-frequency signal is no longer input, the squelch is turned on again, but there is a slight time lag between when the high-frequency signal is no longer available and when the squelch starts, and this squelch opens and closes. At times, large non-electronic noise N appears. This noise N is transferred to the previous control signal sound,
Like the Am and Revised editions, it was of great interest to receivers of personal radios.

In view of the above, the present invention aims to provide a wireless receiver capable of blocking the control signal A4 and the sound j''1 when opening and closing the squelch. do.

Summary of the Invention The present invention provides a detection means for detecting an antinode 11J wave of an audio signal and a control signal, a muting circuit to which the output of the detection means is supplied, and an audio signal circuit to which the output of the muting circuit is supplied. 7, comprising: a control signal detection means for detecting a control signal from the output of the detection means; and a muting pulse generation means for generating a muting pulse;
The wireless receiver is configured to supply a muting pulse from a muting pulse generating means to a muting circuit in response to a detection output from a control borrowing detecting means.
It is possible to improve call quality by blocking the control signal sound and the noise when opening and closing the squelch.

Embodiment An embodiment in which the present invention is applied to a personal radio will be described below with reference to FIGS. 6 to 8. No. 6
The figure shows the reception system of a personal radio, and in the figure,
Portions corresponding to those in FIG. 4 are designated by the same reference numerals and redundant explanation will be omitted.

In FIG. 6, (31) and (32) each indicate an output port, and both output ports (31) and (32) are connected to the CPU (30). (86) is a muting circuit, and this muting circuit (86) is supplied with the output of the integrating circuit (83) as well as the output of the output port (31).

(87) shows an adder circuit, and this adder circuit (87) connects the output of the muting circuit (86) and the output port (32).
The output of the output signal is added to the output of the output signal and is supplied to the low frequency amplifier (84).

For the operation of this example, also refer to flowchart 1 in Figure 8.
explain.

When the radio arrives at 1 o'clock, it receives the frame synchronization signal of the first control signal, and transmits this frame synchronization signal to the modulator/demodulator (4).
When supplied to the CPLJ (30) via the CPU (3
0) directly supplies a muting pulse to the muting circuit (86) via the output port (31), and also supplies a bar f tone burst to the adder circuit (87) via the output port (32). supply. The duration of this high tone burst is set equal to the pulse width of the muting pulse, 043 seconds. Muting circuit (8
6) becomes unable to transmit signals due to the muting pulse, the first control signal sound is emitted from the speaker (9), and then the control signal sound As is replaced by 'C', as shown in FIG. A high tone is emitted.

The frame synchronization signal of the control signal at the end of the JL'r episode is received, and this frame synchronization signal is transmitted to the modulator/demodulator (
4) to the CPU (30), the CPU (
30) directly supplies the signal pulse to the muting circuit (86) via the output port (31), and also supplies the adder circuit (87) via the output port (32).
) is supplied with a low tone burst (Jli). The duration of this low tone burst is also equal to the pulse width of the muting pulse and is set to 0.3 seconds. The mute ink times vF! (86) are As shown in Fig. 7, the final control signal tone and the 1 and 11 sounds N at the time of opening and closing the Skelna are not emitted from the speaker (9), and instead of Af and N. A loud voice called out.

In addition, intermediate control (Fi ! + sound sieve S・1 and ζtel
, the tone burst from the output port (32) is not supplied, and the operation of the muting circuit (86) is limited to &J.

In this way, in this example, each tone of the control signal is muted, and the high tone and low tone of the beginning and ending control signal tones are changed to fv, so that the receiver can You don't have to hear any disturbing sounds, and you can clearly distinguish the beginning and end of a call.

Next, a specific example of the muting circuit (86) shown in FIG. 6 will be explained with reference to FIG. 9. The I signal is transmitted from the input terminal (86i) to the output terminal (86o) via the coupling capacitor Cc. The collector of the transistor (86L) and the J2 transmitter are connected between the output terminal (86o) and the ground, and the I transistor (
Connect the resistor R from the control terminal (86c) to the hearth of the
The control voltage is supplied via a divider consisting of Jt1 and R2. When a control voltage of -1-5V is supplied to the control terminal (86c), the transistor (86t) becomes conductive, grounding the output terminal (016o), and the IllIllaku becomes unable to transmit signals. Become. Control voltage supply 1ll
When the voltage drops, the transistor (861) returns to a non-conducting state and the circuit does not perform a muting operation.

In the above-mentioned embodiment, since the timing is performed after detecting the frame synchronization signal of the received control signal, the bit synchronization signal sound and the frame synchronization signal sound are not heard. .

In order to perform muting on the entire control signal tone, for example, a 7 (i (By inserting a delay line using the +i transfer element, the rising edge of the bit synchronization signal is set before the rising edge of the muting pulse.)

- The delay time Td of this delay line is 54m≧54m.
Selected as 5th.

Note that when the delay time of the delay line inserted in the low frequency signal string is longer than the time from the 1131st frequency signal reception to the squelch signal (1), muting does not occur after the squelch is turned off. Before the squelch signal is heard, a loud sound is heard, so it is necessary to appropriately delay the squelch signal using a CR circuit or the like.

Incidentally, Tone Hurst connects any type of tone, such as continuous tone, 1tli continuous tone, car frequency tone, musical tone, etc.

Effects of the Invention As described in detail above, according to the present invention, the frame synchronization signal of the control signal "iI" is used to compensate for muting, and the start and end control signals are used as a high tone burst and a low tone burst, respectively. By replacing it with
This not only improves call quality but also makes it easier to distinguish between the beginning and end of a call.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a personal wireless device used to explain the present invention, and FIG. 2 is a block diagram showing the configuration of a control signal of the personal wireless system.
3rd IA and B are flowcharts that also do not show the operation of the personal radio device, FIG. 4 is a block diagram showing a part of the reception thread of a conventional personal radio receiver, and FIG. Quimchi to explain the operation of the machine - + - - [
, FIG. 6 shows an embodiment in which the present invention is applied to a personal radio, and FIG. 7 shows a time chart for explaining the operation of the embodiment shown in FIG. 6. The figures are the same (a flowchart showing the operation of the embodiment), and FIG. FIG. 3 is a wiring diagram illustrating a configuration example of a timing circuit. (1) is a transmitter, (2) is a frequency synthesizer, (3)
is a microcomputer, (4) is a modem, (8) is a receiving f3B, (30) is a CPU, (31) and (32)
is an output port, (82) is an FM detector, (86) is a mute ink circuit, and (87) is an adder circuit. Figure 4 Figure 6 J (1 Figure 9 1.1. Figure 5 Figure 7

Claims (1)

[Claims] 1. Detection means for detecting modulated waves of audio signals and control signals, a muting circuit to which the output of the detection means is supplied, and an audio signal to which the output of the muting circuit is supplied. a circuit, a control signal detection means for detecting a control signal from the output of the detection means, and a muting pulse generation means for generating a muting pulse, the muting pulse generating means for generating the muting pulse in response to the detection output of the control signal detection means; A radio receiver characterized in that a muting pulse from a muting pulse generating means is supplied to the muting circuit. 2. Antinode 1 of the audio signal and control signal! A detection means for detecting the J wave, a muting circuit to which the output of the detection means is supplied, an audio signal circuit to which the output of the muting circuit is supplied, and control for detecting a control signal from the output of the detection means. It is equipped with a signal detection means, a muting pulse generation means for generating a muting pulse, and a tone burst generation means for generating a tone burst, and is responsive to the detection output of the control signal detection means. −
A radio receiver characterized in that a muting pulse from the muting pulse generating means is supplied to the muting circuit, and a tone burst from the tone burst generating means is supplied to the audio signal circuit.