JPS6199427A - Tone detector of mobile radio repeater station - Google Patents

Abstract

PURPOSE:To transmit always stably data without interruption of data repeating even if a preamble signal is shortened and is omitted by the tone detection time from the next response signal (the second reception) of a polling signal, by using the output of a gate circuit as a control signal of the repeating operation in press-to-talk mobile radio communication. CONSTITUTION:An input point A is connected to the output of a receiver, and a demodulated tone is subjected to frequency detection by a band pass filter 11 and is subjected to envelope detection by a rectifying verifier 12 and becomes signal '1' or '0'. For example, signal '1' is obtained in case of presence of tone, and signal '0' is obtained in case of absence of tone. This signal is inputted to a delay circuit 21 having a time constant tau only for fall, and the output is inputted to an AND circuit 22. Electric field squelch information from the receiver is inputted to the other input point D of this AND circuit 22, and the AND output is outputted from an output point F to control a repeating switch.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tone detection device that performs relay control depending on the presence or absence of a tone at a relay station in press-to-tone mobile radio communication.

(Prior art) The press-to-tone mobile communication 7 system, which collects boring data between a central station and multiple slave stations via a relay station and controls tone-based F relay operations, is as shown in Figure 3. is shown. That is, when the relay station 1 detects a tone, the polling signal Q-transmitted from the central station 2 turns on the relay switch 5, and is received by the slave stations 3 and 4. The corresponding slave station 3 or 4 that received the polling signal
Next, a response signal to the polling is sent out, which is received by the central station 2 due to the similar operation of the relay station 1.

At first, as a preamble signal, take into consideration the tone detection time for tone relay to turn on at relay station 1, and the time including bit synchronization, etc., and from the second time onwards, in order to increase transmission efficiency, If the tone detection time is omitted,
A relay station may not detect a tone and may not perform a relay operation. This situation will be explained with reference to FIGS. 4 and 5.

Figure 4 is a system diagram of the tone detection section of relay station 1 in Figure 3;
Figures (a) to (h) are timing charts thereof. Generally, in the tone detection section of the relay station I, a polling signal or its response signal is frequency-detected by a band-pass type F-wave device 11, and envelope-detected by a rectification detector 12. In this bandpass type F-wave device 11, since a delay occurs between its input and output A and B, the input signal for the bowing signal (Fig. 5(a)) or response signal (Fig. 5 tdl) K is -7 (5th
The output waveform for Figure (b) or (e)) is Figure 5 (C).
at or (fl. Therefore, when the polling signal and its polling/response signal are continuously received, the composite output waveform (point B) of the output (point B) of the bandpass type F-wave device 11 is In Figure 5 (g)), the left and right envelopes change depending on the phase difference between the falling input wave (C1) and the rising input wave (fl.Incidentally, the worst case occurs when the phase difference between the input waves of the I/C2 wave is . , the envelope of the output level at this time is based on the null point. Therefore, when the composite wave level is low, the output point C of the rectifier detector 12 is turned off (QFF), as shown in FIG. In some cases, the relay switch 5 is turned off and the relay operation is stopped, and in such a case, there is a problem in that the data does not reach the partner station.

(Object of the Invention) An object of the present invention is to provide a stable and efficient tone detection device for a mobile radio relay station by adding a time constant circuit to the relay station tone detection section, thereby eliminating the above-mentioned drawbacks. It is in.

(Configuration of the Invention) The configuration of the present invention provides a tone detection device that extracts and detects a tone signal from a signal in a predetermined frequency band of a received signal in a relay station of mobile radio communication and controls the relay operation. and a gate circuit that takes an AND of the output of the time constant circuit and the electric field squelch signal of the received signal, and uses the output of the gate circuit as a control signal for the relay operation. It is characterized by shortening the 01 preamble signal.

(Principle of the Invention) According to the present invention, a relay station in press-to-tone mobile radio communication has a function of controlling relay operation by detecting a tone such as a tone squelch or control tone. By adding a time constant circuit to the section and performing an AND operation on the tone information and the electric field SGRUTCH information, the data transmission efficiency is increased, and the preamble signal including the tone detection time and bit synchronization is shortened. It is also possible to perform reliable data relay.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram of a relay operation control section of a relay station in an embodiment of the present invention, and FIG. 2 (al to U) is a timing diagram thereof. In the figure, the input point is connected to the receiver output, and the demodulated tone is frequency-detected by a band-pass type p wave detector 11, and then envelope-detected by a rectifier detector 12. It becomes a signal. For example, @ with tone is 1″.

When there is no tone, the signal becomes "0". Next, this signal is input to a delay circuit 21 having a time constant τ only on the falling edge, and its output is input to an AND circuit 22.

The electric field squelch information from the receiver is input to the other input point of the AND circuit 22, and the AND output of these is output from the output point F to control the relay switch.

The AND operation with the electric field squelch here is to prevent noise from being relayed in the case of a weak electric field, but it can be omitted for practical purposes in this data transmission. Also,
In this embodiment, the delay circuit 21 comes after the rectifying detector 12, but the order of these may be reversed.

Next, the timing operation in FIG. 2 will be explained.

The waveforms up to point C in FIGS. 2(a) to (h) are as shown in FIG.
) to (h). Even if the tone detection section is determined at point C even though the central station or slave station is transmitting data, this can be done by preparing a fall time constant τ using the delay circuit 21 with a longer delay time than that time. As in the waveform at the output point E of the delay circuit 21 (FIG. 5(i)), there is no need to judge that the signal is OFF.

10,000, the electric field squelch information is as shown in Figure 5 (j),
Since the output point F of the AND circuit 22 remains at N, the output point F of the AND circuit 22 is always 0N (11), and the relay operation can continue as ON and will not be interrupted.

(Effects of the Invention) As explained above, according to the present invention, the transmission efficiency of the pre-apple signal including the tone detection time and bit synchronization can be improved, so that the next response signal (second reception) of the boring signal Even if the tone detection time is omitted from , data relay is always stable without interruption, and m data transmission can be realized.

'4. stomach,. 96 □□ Fig. 1 is a block diagram of the relay operation control section of the embodiment of the present invention, Fig. 2 (a) to (j) are timing ports showing the operation of Fig. 1, and Fig. 3 is a general block diagram of the relay operation control section. 4 is a block diagram of a conventional relay operation control unit, and FIG. 5 is a timing chart showing the operation of FIG. 4. In the figure, 1... ...Relay station, 2
...Central station, 3, 4...Slave station, 5...
...Relay switch, 11...Band pass type door detector, 12...Rectifier detector, 21...
Delay circuit, 22...AND circuit, A, 1)...
...Input point, C, F'... Output point.

Kaya 1 time Figure 2

Claims (1)

[Claims] A tone detection device for extracting and detecting a tone signal from a signal in a predetermined frequency band of a received signal at a relay station of mobile radio communications and controlling the relay operation, comprising: a time constant circuit that delays the tone detection signal; The preamble signal is shortened by comprising a gate circuit that takes an AND of the output of the constant circuit and the electric field squelch signal of the received signal, and by using the output of the gate circuit as a control signal for the relay operation. A tone detection device for a mobile radio relay station.