JPS5911221B2 - Transmission signal polarity determination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission signal polarity determination method for a time division multiplex transmission system using an RZ long/short code method, in which a main control and monitoring device and a plurality of terminal devices are connected by a pair of signal lines, and the A signal train based on the bipolar RZ long/short code system is transmitted from the main control/monitoring device in a time-division manner, and the terminal device inputs this signal train with each polarity to a charging/discharging circuit, thereby adjusting the output level of the charging/discharging circuit. A pair of gates is provided so that one of the gates is open and the other is closed, and the signal strings on the signal line are connected to the logic circuit of the terminal device through each gate so that the polarity is opposite to each other. The present invention relates to a transmission signal polarity determination method characterized by inputting the polarity of a transmission signal.

An object of the present invention is to automatically determine the polarity of a signal line that transmits a signal string of the RZ long/short code system, and to ensure that the correct signal is received by a terminal device, thereby preventing troubles caused by incorrect wiring, and The goal is to make it easier.

Figure 1 is a basic circuit diagram of a time division multiplex transmission system, where A is the main control and monitoring device, which can also be called the signal generation source, and B1 to Bn.
is a terminal device, and these are connected by a signal line l.

Suppose now that a bipolar signal pulse train as shown in FIG. 2a is being output from the main control and monitoring device A to the signal line l. for example,
The signal sequence shown in FIG. 2a is assumed to be a signal sequence for the terminal device Bi. SPi is a start pulse, P1 to Pm are address code pulses of terminal device Bi and pulses indicating the transmission content (control signal! No. 0), and R is a signal for replying from terminal device Bi to main control and monitoring device A with an 11-code. The pulse SPi+11 is a start pulse for the next terminal device Bi+, and it is assumed that such a bipolar signal pulse train is always sent cyclically to the terminal devices B1 to Bn), and this signal train is
Bi-polar RZ long/short code method (Return to Zero)
It is assumed that it consists of What is RZ long/short code system?
Make sure that there is a pulse at both 'o' and '1', and
This is a coding system in which ``o'' and ``1'' are indicated by different pulse widths. For example, the pulse p in Fig. 2, |μm)
represents "1" (long width), and P2 represents "o" (short width). Therefore, when receiving a signal, the terminal device Bi must always receive the signal with the polarity shown in FIG. 2a. If this signal train is received with the opposite polarity, 35 signal trains as shown in FIG. 2 will be received, and the correct signal will not be received.
The receiving circuits of conventional terminal devices B1 to Bn are configured as shown in FIG. 3, and in this case, the 11 side of the signal lines 1
, 1, and 1 are connected together, the correct reception state is achieved.

That is, the received signal is shaped by a buffer BF via a resistor R1, CR filters R3 and C, and is input to a logic circuit M composed of a signal detection section, an address comparison section, a signal processing section, etc. In addition, in FIG. 3, the power supply for the logic circuit M is obtained from the signal power, which is rectified by the Pritzge BG and then connected to the current limiting resistors R,
The power for the logic circuit M is obtained by smoothing the voltage with a capacitor C1 and making it constant voltage with a Zener diode ZD. Of course, the power source may be obtained from another system. In such a conventional example, since the signal line 1 has polarity,
Wiring work is troublesome, and troubles due to incorrect wiring are likely to occur. Therefore, conventionally, JP-A-53-
As disclosed in Publication No. 34082, the transmission pulse is multipolar signal transmission, and the signal content of one pole and the same signal content are transmitted alternately from the other pole, and the transmission line of the controlled part is A time-division multiplex transmission method has been proposed in which the connection between the However, there was a problem that the transmission speed inevitably became slow. The present invention has been made in view of this problem, and will be explained in detail below with reference to Examples.

FIG. 4 is a circuit diagram of the receiving circuit of the terminal devices B1 to Bn equipped with the transmission signal polarity determination method of the present invention, in which the signal line 11 is
, 12 are one, the diode D2, the resistor R1,
It is input to one input of the AND gate G1 via the filters R, , C2, and at the same time the charge/discharge circuit T1 and the buffer BF are input.
input to the other input of the AND gate Gl through Gl,
The output is input to the OR gate G.

Similarly, a signal that sets signal line 11 to 1 and 1 to + is input to AND gate G, whose output is input to OR gate G, and the output of gate G is input to logic circuit M. The signal is then processed. Here, the charging/discharging circuits Tl, T
, is a charging/discharging circuit determined by resistors R, , R7 and capacitor C4 as shown in FIG. 5, for example. Now, if the signal shown in FIG. 6a is transmitted from the main control and monitoring device A and received with the signal line 11 in the +, 1, and 1 states is the correct signal, then the charging/discharging circuit T1 Since the numerical output as shown in Figure 6b is obtained for the output C of
The input to the gate G1 via the gate becomes H level 21'', and a correct signal output is obtained at the output of the gate G1.

On the other hand, the incorrect signal shown in Fig. 6c is input to the input of the charging/discharging circuit T2, and only the low-level waveform output shown in Fig. 6d is output to the output C''. The input becomes L level "0", and the output of gate G always becomes "02". Similarly, if the connections are reversed, the correct signal can be obtained from the gate G2 side. Therefore, the correct signal will be input to the logic circuit M from the gate G1 through the gate G3. In other words, signal line 1 and terminal devices B1 to Bn
No matter which way the receiving circuit is connected, the characteristics of the signal sequence (
Since the correct signal is always received using the RZ code and the polarity is automatically determined, there are no problems caused by incorrect connections on construction soil. In addition, in the digital data transmission system, a technique of providing a circuit for integrating the transmission signal detected from the transmission line is shown in, for example, Japanese Patent Application Laid-open No. 110204/1983. is for detecting a frame synchronization signal, and is not for determining the polarity of a signal. As described above, the present invention connects a main control monitoring device and a plurality of terminal devices with a pair of signal lines, and transmits a signal train based on a bipolar RZ long/short code system from the main control monitoring device in a time-division manner, In the terminal device, this signal train is input to a charging/discharging circuit with each polarity, and depending on the level of the output level of the charging/discharging circuit,
A pair of gates is provided, one of which is open and the other is closed, and the signal string of the signal line is input to the logic circuit of the terminal device through each gate so that the polarity is opposite to each other. Because of this, it is possible to always receive the correct signal at the terminal device, prevent troubles due to incorrect wiring, and also facilitate the wiring of signal lines.

In particular, the present invention does not stop at simply determining the polarity of a signal train based on the output level of the charging/discharging circuit, but goes further and controls the opening and closing of a pair of gates depending on the level of the output level of the charging/discharging circuit. Therefore, it is possible to automatically select the necessary signals and input them to the logic circuit of the terminal device without manual intervention, and the connection between the signal line and the terminal device can be completely non-polarized. Moreover, regarding the transmission signal waveform, it is necessary to alternately transmit the same signal content from the other pole as in the case of the above-mentioned Japanese Patent Laid-Open Publication No. 53-34082. Therefore, there is an advantage that the transmission speed does not become slow.

[Brief explanation of the drawing]

Figure 1 is a basic circuit diagram of the time division multiplex transmission system, Figure 2 A and b are transmission signal waveform diagrams, Figure 3 is a circuit diagram of a conventional terminal device, and Figure 4 is the transmission signal polarity of the present invention. FIG. 5 is a circuit diagram of a terminal device equipped with a discrimination method, FIG. 5 is a circuit diagram of a charging/discharging circuit same as above, and FIGS. 6 a to 6 d are transmission signal waveform diagrams same as above. A...--Main control and monitoring device, B1-Bn...
・Terminal device, 1 --- Signal line, T1 ---
Charge/discharge circuit, T2...-Charge/discharge circuit, G,, G2
is a gate, and M is a logic circuit.

Claims (1)

[Claims] 1. A main control monitoring device and a plurality of terminal devices are connected by a pair of signal lines, and the main control monitoring device sends out a signal train based on the bipolar RZ long/short code system in a time-division manner, and the terminal device transmits this signal train. Input to the charge/discharge circuit with each polarity,
A pair of gates is provided so that one of the gates opens and the other closes depending on the output level of the charge/discharge circuit, and each gate is connected so that the signal strings on the signal line have opposite polarities. A transmission signal polarity determination method characterized by inputting the polarity of a transmission signal to a logic circuit of a terminal device via a terminal device.