JPS5941621B2 - Signal transmission method - Google Patents

Description

[Detailed description of the invention] In the present invention, a plurality of transport control signals are transmitted from a master unit.

In a signal transmission method in which the transmission of a return signal from a slave unit is controlled by a return signal request signal from a base unit in a 1-N system remote transport control device that controls and monitors a slave unit, the return signal request from the base unit is It is characterized in that the signal is modulated by 5 amplitudes in the handset by short-circuiting it with a carrier frequency, and the amplitude-modulated carrier signal is detected by the base unit to reproduce the return signal of the handset. This relates to a signal transmission method. An object of the present invention is to simplify the circuit configuration of the slave unit by using a carrier signal of a single frequency for signal transmission between the base unit and the slave unit, and to reduce the impedance of the signal line at the base unit. The purpose is to obtain sufficient regeneration ability against fluctuations.

As shown in FIG. The return signals from slave units 3, 4, and 5 are sent to base unit 1 in a time-division manner.

Figure 2 is an example of a time chart when conventional conveyance is applied.As shown in Figure 2a, frame synchronization pulse P1, channel pulse P2,
, control pulse P3 is sent from slave units 3, 4, and 5 to base unit 1.
P3 and a pulse P4 indicating the return time period are sent to the receiver, and a return signal pulse P5 as shown in FIG. Here, the base unit 1 distinguishes the return signal pulse P5 returned during this return time period from the return signal from the slave units 3, 4, and 5 specified (called) by the channel pulse P2. It's summery. In such a control signal transmission system,
When trying to transmit pulses using a carrier signal,
Pulse P4 indicating the return signal time period from base unit 1 and slave unit 3
Since the return signal pulses P5 from , 4 and 5 overlap, 2
frequency carrier signals had to be used. That is, in Fig. 2c, the pulse of Fig. 2a is transmitted by amplitude modulation of the carrier signal, and when the pulse of Fig. 2a is ゛゜H'', the carrier signal of frequency fl is transmitted from the base unit 1 to the slave unit. 3, 4, and 5, and when it is "L", no carrier signal is sent. FIG. 2d shows return signals sent from slave units 3, 4, and 5 to base unit 1, which is also an example of transmission using amplitude modulation. In this case, the return signal must have a frequency of f2, which has the disadvantage that the circuit configurations of the handsets 3, 4, and 5 become complicated. The present invention has been made in view of this point, and will be explained in detail below with reference to Examples. Figure 3 is a time chart of signals transmitted by the signal transmission method of the present invention, and Figures A and b are Figures 2A and 3B.
This is the same as b, and at this time, from base unit 1 to slave units 3, 4, 5
As shown in FIG. 3c, an amplitude modulated signal of frequency f is sent to the same as in FIG. 2c.

Here, when slave units 3, 4, and 5 have to send back signals on their own channels during the return signal time,
When the carrier signal is at the "H" level, the carrier signal is short-circuited. That is, when the frequency of the carrier signal is f, when the return signal is at the "H" level, the frequency of the carrier signal is Short-circuit between the signal lines 2 with a series resonator of f,
At this time, the waveform detected by the base unit 1 is a waveform in which the carrier signal is interrupted when the slave units 3, 4, and 5 send a return signal, as shown in FIG. 3d, and this waveform is detected to reproduce the return signal. In addition,
Base unit 1 also receives and reproduces its own transmitted signals, but as in the conventional example, the signals received during the preset return time period are used as return signals from slave units 3, 4, and 5. It will be fine if you play it as .

Figure 4 shows the carrier signal short circuit when generating return signals for slave units 3, 4, and 5, where L1 is a coil, C1 is a capacitor, BDl is a full-wave rectifier, Q1 is a transistor, R1 is a resistor, and 6 is a return signal generator. It is a circuit.

Figure 5 shows the return signal regeneration circuit from the slave units 3, 4, and 5 of the base unit 1, where C2, C3, and C4 are capacitors, T1 is a transformer, R2 to R6 are resistors, Dl and D2 are diodes, and Q2 is a comparator. , 7 is a carrier signal amplitude modulation circuit. FIG. 6 is a signal waveform diagram of each part in FIG. 5, FIG. 6 a is a return signal time gate, FIG. 3 is an output voltage waveform diagram of the amplitude modulation circuit 7. FIG. Figure 6c shows the return signal pulses from slave units 3, 4, and 5, Figure 6d shows the carrier waveform on the secondary side of the transformer T1 in Figure 5, and depending on the impedance state of the signal line 2, Figure 6a This shows that the amplitudes are different between A and B in the return signal time period. 6. FIG. 6 shows the input waveform of the comparator Q2, and C and D are the voltage waveforms of the comparator Q2 for one-man power and ten-man power, respectively. FIG. 6f shows the output waveform of comparator Q2. Now, in the handsets 3, 4, and 5, the transistor Q1 is turned on and off by a return signal pulse as shown in FIG. 3b from the return signal generation circuit 6.

Here, if transistor Q1 turns on, full-wave rectifier B
Dl is on, signal line 2 is connected to coil L1 and capacitor D1
short-circuited by a series resonant circuit formed by here,
If the series resonance frequency is made to match the carrier frequency, when the signal from the return signal generation circuit 6 is "H", the signal line 2 will be short-circuited about the carrier frequency, and the carrier signal waveform from the slave units 3, 4, and 5 will be The result will be as shown in Figure 3d. Next, the return signal reproducing circuit of base unit 1 will be described. The carrier signal from the amplitude modulation circuit 7 has a constant impedance due to the resistor R2, and is superimposed on the signal line 2 via the transformer T1 and the capacitor C2. Here, when the carrier signals are short-circuited in the handsets 3, 4, and 5, a waveform as shown in FIG. 6d is obtained on the secondary side of the transformer T1. This waveform is detected by a detection circuit consisting of a diode D1, a capacitor C3, a diode D2, and a capacitor C4. Here, the time constant of the detection circuit consisting of diode D1 and capacitor C3 is selected to be 6 times smaller than that capable of sufficiently detecting the amplitude-modulated carrier wave, and is input to the single power of comparator Q2. Among the amplitude-modulated carrier waves, the constant is selected so large that there is no level fluctuation when short-circuited by the return signals from slave units 3, 4, and 5, and the waveform after detection is divided by resistors R5 and R6. Then, apply force to converter Q2 (Fig. 6e). As a result, the output of comparator Q2 is
The return signals from slave units 3, 4, and 5 are reproduced as shown below.
Furthermore, even if the impedance of signal line 2 changes and the level of the carrier signal changes, the comparison value of comparator Q2 (voltage of 100%) also changes in response to the change in the carrier signal level, so the impedance of signal line 2 The ability to reproduce the returned signal improves in response to fluctuations. Fig. 7 is a circuit diagram of another embodiment of the return signal regeneration circuit of base unit 1, in which a negative bias is applied by power supply E to the detection circuit applied to the power terminal of comparator Q2, and it is the same as that shown in Fig. 5. The same effects can be obtained.

That is, in the embodiment of FIG. 5, the voltage across the capacitor C4 is divided by the resistors R5 and R6 to obtain a comparative value (voltage of 10 human forces) that is slightly lower than the peak value of the single force waveform C of the comparator Q2. In FIG. 7, a negative power supply E is used as a voltage reducing means for setting a comparison value in place of the voltage reducing means using the voltage dividing resistors R5 and R6.

As in the present invention, the return signal request signal from the base unit is amplitude-modulated by short-circuiting it with a carrier frequency in the slave unit, and the amplitude-modulated carrier signal is detected by the base unit and sent to the slave unit. Since the return signals of This has the effect that sufficient reproduction ability can be obtained against impedance fluctuations.

[Brief explanation of drawings]

Figure 1 is a basic circuit diagram of a general signal transmission system, Figure 2 a-
d is a time chart of a signal transmitted by the conventional signal transmission method, FIG. 3 a to d is a time chart of a signal transmitted by the signal transmission method of the present invention, and FIG. 4 is a carrier signal short circuit of the slave device of the present invention. A circuit diagram of an embodiment of the circuit, FIG. 5 is a circuit diagram of an embodiment of the return signal reproducing circuit of the base unit of the present invention, and FIG.
Figures a to f are signal waveform diagrams similar to the above, and Figure 7 is a circuit diagram of another embodiment of the return signal reproducing circuit of the base unit. 1... Master unit, 3, 4, 5... Slave unit, Ll, CBI, coil capacitor that forms a series resonant circuit to short-circuit with slave unit, Cl, C3... Diode that forms a detection circuit. , capacitor, D2, C4...Diode and capacitor forming a detection circuit.

Claims (1)

[Claims] 1 Signal transmission in a 1-N system remote transport control device that controls and monitors multiple slave units using transport control signals from the base unit, such as controlling the transmission of return signals from the slave units based on a return signal request signal from the base unit In this method, a carrier signal indicating a return time period, which is sent from a base unit following a return signal request signal, is amplitude-modulated in a slave unit by short-circuiting it with a series resonator whose resonance frequency is equal to the carrier frequency, and the amplitude modulation is performed by A signal transmission system characterized in that a base unit detects a carrier signal in a return time period and reproduces a return signal from a slave unit.