JP2814946B2 - 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 device, and more particularly to an interrupt communication control method in a half-duplex communication system using a single frequency having a master station and a plurality of slave stations.

[0002]

2. Description of the Related Art In a conventional half-duplex communication system of this type, when communication is performed between a master station and a plurality of slave stations, an interrupt communication control system is adopted.
No. 861 discloses the details.

[0003] Briefly describing this interrupt communication control system, a master station periodically sends an interrupt synchronizing signal to each slave station, and each slave station forcibly receives the interrupt synchronizing signal for a certain period of time every time it receives this interrupt synchronizing signal. It switches to the mode and monitors whether there is an interrupt from another slave station. If an interrupt signal from another slave station is detected during the monitoring of the presence or absence of the interrupt, thereafter, the mode is switched to the reception mode and communication is performed.

FIG. 4 is a block diagram showing an example of such a half-duplex communication type slave station communication device, and FIG. 5 is an example of a time chart showing operation waveforms of respective parts.

At the time of radio communication, a transmission radio wave (frequency f1) of the periodic interrupt synchronization signal from the master station is received by the antenna 6 and converted into a signal of a predetermined frequency by the high-frequency amplifier 4 via the antenna switching unit 5. The signal is converted and demodulated by the demodulation unit 3 into a baseband signal.

When detecting an interrupt synchronizing signal (not particularly shown in FIG. 5) from the demodulated signal K, the control signal detecting section 10 generates a control signal L (period t2) each time the interrupt synchronizing signal is detected and outputs the control signal L (period t2). Send to Interrupt control unit 11
When the control signal L is generated in the transmission mode (the transmission drive signal J is at a low level), the transmission control signal M
For a certain period (t3).

During the forced reception mode (t3), the control signal detector 10 monitors whether or not the interrupt signal K from another slave station has been received. Is held until the transmission drive signal J is released (high level) and driven again (low level),
The receiving mode is set to receive the interrupt communication signal.

Reference numeral 1 denotes a modulation unit for modulating the transmission signal I. Reference numeral 2 denotes a power amplifying unit, which amplifies the power of the modulated signal of the modulation unit 1 and sends it to the antenna 6 via the antenna switching unit 5.

[0009]

Conventionally, in an interrupt control system of this type of wireless communication device, each slave station receives an interrupt synchronization signal from a master station and generates an interrupt control signal L synchronized with the system. The receiving mode is forcibly set in synchronization with the generation timing, and interrupt communication is enabled. Therefore, the interrupt control is performed reliably, but there is a problem that the communication is interrupted because the reception mode is forcibly set during the communication.

It is an object of the present invention to provide a radio communication device which eliminates interruption of a call at the time of interrupt monitoring.

[0011]

According to the present invention, there is provided a voice signal presence / absence detecting means for detecting a break in a transmission signal in a transmission mode, and a transmission for a predetermined period in response to the detection of the break in the transmission. Interrupt signal detecting means for canceling the mode, forcibly switching to the reception mode, monitoring the reception signal line and controlling to switch to the reception mode when the interruption signal is detected, and the transmission signal during the forced reception mode for the predetermined period. And a delay control means for deriving the delayed transmission signal as a transmission output after the predetermined period has elapsed.

Further, according to the present invention, a master station wireless communication device for periodically transmitting an interrupt synchronization signal, and canceling the transmission mode for the predetermined period in response to reception of the interrupt synchronization signal from the master station. A plurality of slave stations configured to detect the presence or absence of an interrupt signal from another wireless communication apparatus and to set the reception mode thereafter upon detection of the interrupt signal, wherein the master station includes: A slave station wireless communication device in a wireless communication system configured to perform communication between a wireless communication device and the plurality of slave station wireless communication devices, the presence or absence of a voice signal for detecting a break in a transmission signal in a transmission mode. Detecting means; means for generating a control signal for canceling the transmission mode for a fixed period of time and forcibly switching to the reception mode in response to the detection of the break at the time of transmission; and monitoring the reception signal line to interrupt the interruption. Interrupt signal detection means for controlling switching to a reception mode when a signal is detected, and delay control for delaying the transmission signal in the forcible reception mode for a predetermined period and deriving the delayed transmission signal as a transmission output after the predetermined period has elapsed. And a slave station wireless communication device characterized by comprising:

[0013]

In order to detect the presence / absence of a transmission during transmission and to forcibly monitor the interruption as the reception mode only when there is no transmission signal, and to eliminate interruption of the transmission signal during the monitoring. The delay control of the transmission signal is performed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and the same parts as those in FIG. 4 are denoted by the same reference numerals. FIG. 2 is a timing chart of signal waveforms of respective parts representing the operation of the embodiment of FIG.

First, a transmission signal A is subjected to a predetermined modulation by a modulation section 1 which is activated and controlled by a transmission drive signal B, and is amplified to a predetermined transmission output by a power amplification section 2. It is radiated to the space by the antenna 6 via the antenna.

An interrupt control operation is performed in parallel with the transmission operation. That is, the transmission signal A is sent to the modulation unit 1 and sent to the audio signal presence / absence detection unit 7 to detect the presence / absence of an audio signal. In response to the detection signal C, the interrupt signal detection control unit 8 controls the switch 12 with the control signal D to forcibly cut off the transmission drive signal B when there is no audio signal for only a predetermined time t1 (about 100 msec), and changes the reception state. I do.

At the time of interrupt control, in order to avoid interruption of the transmission signal A, the interrupt signal detection control section 8 outputs the control signal F to control the switch 13 and delays (about 100 msec) via the delay control section 9. Selected transmission signal. In this forced reception state, the interrupt signal H is demodulated via the antenna switching unit 5, and when this is detected by the interrupt signal detection control unit 8, the control signal D is output so as to maintain the forced reception state. . This control state operates so that the transmission drive signal B is maintained until the redrive control is performed.

The operation of the embodiment of the present invention has been described above. The operation will be described in more detail with reference to the timing chart shown in FIG. When the transmission drive signal B is set to the transmission state (low level) for transmission, the presence / absence of the transmission signal A is detected by the voice presence / absence detection unit 7. High level is output.

A control signal D and a control signal F are generated by the interrupt signal detection controller 8 based on the detection signal C. The control signal D forcibly disconnects the transmission drive signal line for a predetermined time t1 (about 100 msec), and the transmission control signal E
To a high level.

The control signal F controls the switching to the transmission signal delayed (about 100 msec) by the delay control unit 9 in order to avoid interruption of the transmission signal A in the forced reception state. When the interrupt control signal H is received in the forced reception state, the interrupt signal detection control unit 8 detects this, and the control signals D and F are controlled until the transmission drive signal B becomes the reception state (high level). Held in state.

FIG. 3 is a circuit diagram of a specific example of the interrupt signal detection control section 8 of FIG. 1, which is composed of a gate circuit, a flip-flop (FF) and the like, and is not limited to the circuit example of FIG. Of course, it can be realized not only by a hardware configuration but also by a software configuration such as a microprocessor.

In FIG. 3, a control signal D for turning off the switch 12 to enter the forced reception mode needs to be at a high level for a fixed time t1 in a silent state in the transmission mode. Therefore, the AND logic of the audio signal presence / absence detection signal C and the inverted signal of the transmission drive signal B by the inverter 32 is taken by the gate 31, and the gate 33 and the FF3
The change timing of the AND logic is detected by the differentiating circuit 4.

In response to this change timing, a monostable multivibrator 35 whose time constant is set to t1 is triggered to turn on a switch circuit including gates 37 to 39 and an inverter 40 via a NAND gate 36,
The control signal D is at a high level for a certain time t1.

Further, the control signal D needs to be at a high level in response to the detection of the interrupt signal to enter the reception mode. Therefore, the received signal H is monitored, demodulated by the demodulation unit 41, and compared with the reference interrupt signal by the comparator. If they match, an interrupt signal is detected, so that the FF 43 is set. In response to the set output of the FF 43, the switch circuit (gates 37 to 39 and inverter 4)
0) is turned on.

It should be noted that this reception mode state must be maintained until the transmission drive signal B is re-driven, so that the transmission drive signal B is input to the NAND gate 39 constituting the switch circuit. It is.

A control signal F for turning on the switch 13 to obtain a delayed output of the transmission signal A is at a low level in the transmission mode and when the transmission silence is detected. Must be maintained until the signal becomes a reception state (high level). Therefore, the FF 46 is set by the output of the AND gate 33, the set output is used as the control signal F, and the transition timing of the transmission drive signal B is detected by the differentiating circuit including the gate 44 and the FF 45, and the FF 46 is reset. I have to.

It is assumed that a clock signal which is a clock input to the FFs 34 and 35 constituting the differentiating circuit is a block having a high frequency with a cycle smaller than the operation cycle of each section signal.

[0029]

As described above, according to the present invention, the presence or absence of a transmission is detected during transmission, the forced reception state is set only when there is no transmission signal, the interrupt signal is monitored, and the transmission during this monitoring is performed. Since the delay control for eliminating the break of the talk signal is added, there is an effect that the synchronization with the master station is not required and the break of the call is eliminated.

[Brief description of the drawings]

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

FIG. 2 is a signal waveform diagram of each part showing the operation of the block in FIG. 1;

FIG. 3 is a specific example circuit diagram of an interrupt signal detection control unit 8 of the block in FIG. 1;

FIG. 4 is a block diagram of a conventional wireless communication device.

FIG. 5 is a signal waveform diagram of each part showing the operation of the block in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Modulation part 2 Power amplification part 3 Demodulation part 4 High frequency amplification part 5 Antenna switching part 6 Antenna 7 Audio signal existence detection part 8 Interruption signal detection control part 9 Delay control part 12, 13 switch

Claims (3)

(57) [Claims] 1. An audio signal presence / absence detecting means for detecting a break in a transmission signal in a transmission mode, and a transmission mode being forcibly released for a predetermined period in response to the detection of the transmission break. And interrupt signal detection means for monitoring the reception signal line and switching to the reception mode when the interruption signal is detected, and delaying the transmission signal during the forcible reception mode for the predetermined period and delaying the transmission signal after the predetermined period has elapsed. And a delay control means for deriving a transmission signal as a transmission output. 2. A master station wireless communication device for periodically transmitting an interrupt synchronization signal, and in response to receiving the interrupt synchronization signal from the master station, canceling the transmission mode for a predetermined period and forcibly changing to a reception mode. Including a plurality of slave station wireless communication devices configured to detect the presence or absence of an interrupt signal from another wireless communication device and to set the reception mode thereafter when the interrupt signal is detected, the master station wireless communication device and the A slave station wireless communication device in a wireless communication system configured to perform communication with a plurality of slave station wireless communication devices, wherein an audio signal presence / absence detecting means for detecting a break in a transmission signal in a transmission mode. Means for generating a control signal for canceling the transmission mode for a fixed period of time and forcibly switching to the reception mode in response to detection of a break during transmission, and monitoring a reception signal line to detect a reception mode when the interrupt signal is detected. Interrupt signal detection means for controlling to switch to a mode, delay control means for delaying the transmission signal in the forcible reception mode for the predetermined period, and for deriving this delayed transmission signal as a transmission output after the predetermined period, A slave station radio communication device comprising: 3. The wireless communication device according to claim 1, wherein the delay control unit is configured to cancel the delay control operation in the next transmission mode.