JPH0457412A - Selecal system - Google Patents

Abstract

PURPOSE:To effectively utilize a time after an opposite tone signal is detected for clock recovery and to attain reception immune to external noise by sending a bit synchronization signal as a dummy data before tone squelch rises. CONSTITUTION:A control section 1 outputs a TX ON signal 1.1 to a radio reception section 2 at transmission to start the transmission of a radio wave, outputs a tone designation signal 1.2 to a tone transmission circuit 3 and a coding circuit 4 and outputs a tone signal 3.1 to the radio transmission/reception section 2. A radio equipment of an opposite station receiving the tone signal discriminates whether or not the frequency of the tone signal is equal to a tone frequency of its own station and starts the reception when the frequency is related to its own station to detect the bit synchronization period for a prescribed length required for the clock recovery after the bit synchronization, and when the frequency is not related to its own station, the further reception is not progressed. Thus, a digital SELECAL data is surely received by an opposite party and the transmission/reception processing of the data is finished in a possibly short time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a radio device that performs a select call based on digital data using a tone squelch, and a radio device that performs a select call based on digital data using a relay station that performs a relay function using the tone squelch. It is related to.

[Summary of the invention]

The present invention aims to secure more subsequent communication time by quickly starting up the tone squelch circuit of the other party's radio device or relay station and efficiently completing the transmission and reception of select call data. For this purpose, after transmitting a tone for a margin time during the rise time of the other party's tone reception operation,
Rather than transmitting a select call using digital data, a method is adopted in which the transmission of digital data is started at the same time as tone transmission, and a bit synchronization signal (BS) is superimposed during a time period corresponding to the rising time of the other party + margin time. According to this method, the bit synchronization signal is received during the margin time after the tone reception operation starts depending on the ability of the other party, and the burst due to disturbance in the clock regeneration operation of the digital data reception circuit. It has the effect of increasing resistance to noise.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional digital selector data sending method, and FIG. 4 is a timing diagram explaining the operation of FIG. 3. 1 in the figure is the control unit.

2 is a radio transmitting/receiving section, 3 is a tone transmitting circuit, 4 is an encoding circuit, 5 is a modulating circuit, 6 is an adding circuit, 7 is a demodulating circuit, 8 is a tone receiving circuit, 9 is a determination circuit, and 10 is a decoding circuit. be.

Next, the structure and operation of the prior art will be explained with reference to FIGS. 3 and 4. At the time of transmission, the control unit 1 outputs a TX ON signal 1.1 to the wireless transmission/reception unit 2 to start transmitting radio waves, and outputs a tone designation signal 1.2 to the tone transmission circuit 3.
Tone signal 3.1 is modulated input signal 6.1 via addition circuit 6
It is output to the wireless transmitting/receiving section 2 as a. When this tone signal is received, the radio of the other station determines whether the tone frequency belongs to its own station, and if so, starts receiving operation.
Tone squelch control is performed to prevent further reception operation if the condition does not apply. In addition, when a tone signal is received at a relay station that uses a tone, it determines whether the frequency is a tone frequency to be relayed, and if the tone signal is found, it starts a relay operation, and if it is not, it does not perform a relay operation. In order to perform a selection call using digital data,
The control unit 1 outputs the selector data 1.3 to the encoding circuit 4, and the modulation circuit 5 modulates the predetermined encoded data 4.1. A tone signal 3.1 is superimposed on this modulated signal 5.1 by an adder circuit 6 to obtain a modulated input signal 6.1. Data transmission is controlled at the timing shown in Figure 4 in order to ensure that the other party receives the digital selector data, complete the data transmission and reception process in the shortest possible time, and then carry out the main purpose of communication. are doing. Bit synchronization (BS), frame synchronization (FS) after T1+T2 time elapses after outputting TX ON signal 1.1 from control unit 1
, data (DATA), T1 is the time required for the other station to detect the tone, and T2 is the margin time taking into account the transmission system including the device. The partner station detects the tone after T1 has elapsed and starts receiving operation, and after T3 has finished receiving the select call data, communication is possible. This receiving operation is similar to that performed by the device that transmits the call, and will be explained with reference to FIG. 3. When the wireless transmitting/receiving section 2 receives a radio wave, it outputs a demodulated output 2.1 to the demodulating circuit 7 and the tone receiving circuit 8.

When the tone detection signal 8.1 is obtained from the tone reception circuit 8, the determination circuit 9 starts the subsequent reception operation. The demodulation ratio cuff, 1, of the demodulation circuit 7 is decoded by the decoding circuit 10 as a received signal via the determination circuit 9, and the received data 10.1 is analyzed by the control unit, completing the reception of the select call data.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, since the transmission of the select call data is started after waiting the tone detection time of the other station + the margin time,
There is a drawback that an invalid time period exists between the actual tone detection timing and the selector data transmission start timing. In order to solve this drawback, the present invention aims to make effective use of the above-mentioned invalid time period and ensure that the transmission and reception of SELECALL data is completed more quickly and reliably.

[Means to solve the problem]

In order to achieve the above object, the present invention activates the tone transmission circuit at the same time as the transmission of radio waves starts, and at the same time activates the bit synchronization transmission of the encoding circuit. (Synchronization and data) Bit synchronization is always sent during the sending timing.

[Effect]

As a result, in the operation of receiving select call data from the other station, clock regeneration can be started at an earlier timing, and the required bit synchronization (BS) of a predetermined length can be detected more stably, so that It is also resistant to burst noise that occurs at the timing of , and can improve the stability of SELECALL data reception.

〔Example〕

An embodiment of the present invention will be described below with reference to the block diagram of FIG. 1 and the timing diagram of FIG. 2. 1 to 10 in the figure are the same as the same parts as in FIG. 3, and some results are different from FIG. 3.

At the time of transmission, the control unit 1 outputs the TX ON signal 1.1 to the radio reception unit 2 to start transmitting radio waves, and also encodes the tone designation signals 1 and 2 to be output to the tone transmission circuit 3 and the encoding circuit 4. circuit activation).

Tone signal 3.1 is sent via addition circuit 6 and bit synchronized (B
S) The signals 4,1 are outputted to the wireless transmitting/receiving section 2 as modulated input signals 6,1 via the modulating circuit 5 and the adding circuit 6. When this tone signal is received, the other station's radio equipment determines whether the tone frequency belongs to its own station, and if so, starts reception operation, and performs tarok regeneration from the bit period and bit synchronization of the required predetermined length. Detection is performed, and if the condition does not match, tone squelch control is performed to prevent further reception operation. Furthermore, when a tone signal is received at a relay station that uses a tone, it determines whether or not the tone frequency is to be relayed, and if it is, it starts a relay operation, and if it is not, it does not perform a relay operation. In order to perform a select call using digital data, the control unit 1 outputs select call data 1.3 to the encoding circuit 4, and following the bit synchronization (BS) signal that is already being output, frame synchronization and data 4 which have been encoded in a predetermined manner are generated. .1 is modulated by the modulation circuit 5. A tone signal 3.1 is superimposed on this modulated signal 5.1 by an adder circuit 6 to obtain a modulated input signal 6.1.

Data transmission is controlled at the timing shown in Figure 2 in order to ensure that the other party receives the digital select call data, complete the transmission and reception process of this data in the shortest possible time, and carry out subsequent communication, which is the main purpose. do. After outputting TXON signal 1.1 from control unit 1, T1+T2+T
After 4 hours.

Digital selector data consisting of frame synchronization (FS) and data (DATA) is sent.

T1 is the time until the other station can detect the tone,
T2 is a margin time considering the transmission system including the device, and T4 is a time corresponding to bit synchronization (BS) in the conventional method.

The partner station detects the tone after T1 has elapsed and starts receiving operation, and enables communication after T3 has elapsed when reception of the select call data ends. This receiving operation is similar when receiving a fillet call in a device that transmits a fillet call, and will be explained with reference to FIG. When the wireless transmitting/receiving section 2 receives a radio wave, it outputs a demodulated output 2.1 to the demodulating circuit 7 and the tone receiving circuit 8. Tone detection signal 8.1 from tone receiving circuit 8
When obtained, the determination circuit 9 starts the subsequent reception operation. The demodulated output cuff 1 of the demodulation circuit 7 is decoded by the decoding circuit 10 as a received signal via the determination circuit 9 and is received data 1.
o, 1 is analyzed by the control unit 1, and reception of the selector data is completed. At the timing shown in FIG. 2, it should be possible to receive bit synchronization during the time period T2.

There is a possibility that the time T3 until receiving a SELECALL can be further shortened by deleting the T4 time to shorten the SELECALL transmission/reception time, or by shortening the T2 time by adding judgment on environmental conditions.

〔Effect of the invention〕

According to the present invention, by transmitting bit synchronization as dummy data before the start of the tone squelch operation without changing the basic configuration, the clock can be regenerated for the time after the other party's tone is detected. Not only can it be used effectively and enables reception that is resistant to external noise, but it also enables the original communication time to be established more quickly because the timing of sending and receiving SELECALL data can be advanced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a timing diagram showing the operation of the present invention, FIG. 3 is a block diagram showing the conventional configuration, and FIG. 4 is a timing diagram showing the conventional operation. be. a control section, 2: wireless transmitter/receiver section, 3: tone transmitter circuit, 4
: encoding circuit, 5: modulation circuit, 6: addition circuit, 7: demodulation circuit, 8: tone reception circuit, 9: determination circuit, 10: decoding circuit.

Claims (1)

[Claims] 1. In a radio device that constitutes a transmission system consisting of a control unit that controls the transmission of radio waves, tone transmission, and SELECALL data transmission, a tone transmission circuit, an encoding circuit, a modulation circuit, an addition circuit, and a radio transmission/reception unit, from the control unit The wireless transmitting/receiving unit starts transmitting radio waves with the activation signal, and at the same time, a tone signal is generated by activating the tone transmission circuit, and a bit synchronization signal is obtained via the modulation circuit by activating the encoding circuit, and the two are added to the adder circuit. By combining this signal with the modulated input signal of the wireless transmitting/receiving unit, the transmission of select call data that is performed prior to communication is superimposed on the tone transmission from the time of radio wave transmission, and bit synchronization transmission is started, and the tone of the other station is The select call method is characterized by starting frame synchronization and data transmission at the timing when detection ends.