JPH03186033A - Signal transmission system - Google Patents

Abstract

PURPOSE:To eliminate the need for exclusive control by enabling two signal input/output devices which transmit digital signals mutually to detect the sent signals from the opposite devices even when sending the signals through a couple of signal transmission lines simultaneously, and then enabling the both to send and receive the signals simultaneously even through one signal transmission line. CONSTITUTION:The sent signals sent from transmission parts A and B to the same signal transmission line 13 are multiplexed by signal multiplexing parts of signal input/output parts 1a and 2a and then signal demultiplexing parts demultiplex their sent signals and opposite-side sent signals from the multiplexed signals. Only the sent signal of each side is removed from the demultiplexed sent signal and the sent signal of the opposite side is inputted to a signal input part and thus received. The opposite-side signal input/output part also performs the same operation to receive the signal sent through the same signal transmission line 13. Both the parts A and B can send and receive the signals simultaneously through the one signal transmission line 13 and the need for exclusive control is eliminated.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an input/output device of a computer or an input/output interface of a communication control device, and particularly to a signal input/output device that inputs/outputs signals simultaneously with a plurality of input/output devices. This relates to a transmission device.

[Conventional technology]

Conventionally, as this type of signal transmission system, there has been one shown in FIG. Figure 3 is a circuit diagram for conventional signal transmission. In the figure, (1) and (2) are input/output interface circuits on the A side and B side, and (3) and (4) are signal transmission drivers. , (5) and (6) are receivers for signal reception, (7) and (8) are input signal lines for transmission signals, (9) and (10) are output signal lines for reception signals, (1
1) and (12) are selection signal lines for switching between transmission and reception, and (13) is a signal transmission line for connecting between the A-side and B-side input/output interface circuits (1) and (2).

Next, the operation will be explained. When transmitting a signal from the input/output interface circuit (1) on the A side to the human output interface circuit (2) on the B side, set the selection signal line (11) of the input/output interface circuit (1) on the A side to logic 1. The driver (3) is enabled and the receiver (5) is disabled. On the other hand, the input/output interface circuit (2) on the B side, which is the signal receiving side, sets the selection signal line (12) to logic O, disables the driver (4), and enables the receiver (6). state.

Next, by manually inputting a signal from the input signal line (7) of the transmission signal of the input/output interface circuit (1) on the A side, the signal is output from the driver (3), and the signal is transmitted through the signal transmission line (
13) on the B side via the human output interface circuit (
A signal is transmitted to 2). As a result, in the B-side human output interface circuit (2), the transmitted signal is received by the receiver (6) and outputted to the received signal output line fg (10). While the human output interface circuit (1) on the A side is transmitting, the signal transmission path (13) is occupied, so the human output interface circuit (2) on the white side cannot transmit. (4) must be kept inoperable. On the other hand, when transmitting a signal from the B-side input/output interface circuit (2) to the A-side input/output interface circuit (1), the selection signal line (12) of the B-side human output interface circuit (2) is 1 to enable the driver (4) and disable the receiver (6). On the other hand, the input/output interface circuit (1) on the A side, which is the signal receiving side, sets the selection signal line (11) to logic O, and the driver (3)
The receiver (5) is made inoperable and the receiver (5) is made operable. Next, the B-side human output interface circuit (2
) by inputting a signal from the transmission signal input signal line (8), the signal is output from the driver (4), and is sent to the human output interface circuit (1) on the A side via the signal transmission line (13). A signal is transmitted. The input/output interface circuit (1) on the A side transmits the transmitted signal to the receiver (
5) receives the signal and outputs it to the output signal line (9) of the received signal. While the input/output interface circuit (2) is transmitting, the human output interface circuit (1) on the A side cannot transmit because the signal transmission path (3) is also occupied. ) must be kept inoperable.

(Problem to be solved by the invention) Since the conventional signal transmission method is performed as described above, if both output interface circuits of each person transmit data at the same time, each other's transmitted data will be destroyed on the signal transmission path. Therefore, signals can only be transmitted from one input/output interface circuit, and therefore, when transmitting signals, it is necessary to perform exclusive control between one input/output interface circuit, such as stopping signal transmission or stopping signal reception. ,
Signal transmission procedures become complicated. Also, since data cannot be transmitted and received simultaneously on both input and output interface circuits,
It is necessary to perform data transmission and reception in a time-division manner, which poses problems such as the time it takes to transmit and receive data.

The present invention has been made to solve the above-mentioned problems, and aims to provide a signal transmission system in which both parties simultaneously transmit and receive signals on one signal transmission path and do not require exclusive control.

[Means to solve the problem]

In the signal transmission method according to the present invention, a signal transmission path is arranged between each signal output section of the first and second signal input/output devices, and each signal input/output device has a signal output from its own signal output section. a signal combining section that combines the signal and the signal output from the signal output section of the other party; a signal separating section that separates each output signal from the combined signal; and a signal separating section that separates each output signal from the combined signal;
The device is provided with a signal removing section that removes its own output signal and outputs the other party's output signal to the signal input section.

[Effect]

According to this invention, after the transmission signals from each transmitting unit transmitted on the same signal transmission path are combined in the signal combining unit in each signal output unit, these combined signals are used to combine the own transmission signal and the other side's transmission signal. A signal separation section separates the transmitted signal from the transmitted signal, and removes only the own transmitted signal from these separated transmitted signals.
Inputs the transmission signal of the other party to the signal input section and receives the other party's signal.On the other hand, the signal input/output section of the other party performs the same function and receives the signal transmitted via the same signal transmission path. do.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. still,
In FIG. 1, the same reference numerals as in FIG. 3 indicate the same or corresponding parts. In the figure, (IA) and (2A) are input/output interface circuits on the A side and B side in this embodiment, (
21), (22) are detection resistors, (23) (24)
, (25), (26) are the detection resistors (21),
A comparator for detecting the potential difference of (22), (2
7), (28), (29).

(30) is a logic element, which is a NOR gate, (31), (
32) is a logic element and is an AND gate, (33), (3
4) is a logic element and is an OR gate. FIG. 2 is a truth table for explaining the operation of FIG. 1.

Next, the operation of this embodiment will be explained. The human input signal line for the transmission signal of the input/output interface circuit (IA) on the A side (
7) and the input/output interface circuit on the A side (IAJ side) when a signal as shown in Fig. The output signal of the output signal line (9) of the received signal will be explained.

In the case of signal state case 1 shown in Figure 2, since logic 0 is input to the human output signal lines (7) and (8) of both transmission signals, the outputs of both drivers (3) and (4) becomes logic O, and there is no potential difference, so the detection resistor (21)
The current does not flow through the comparators (23) and (25
) also becomes 0, and the outputs of the comparators (23) and (25) both output logic O.

Therefore, the output of the NOR gate (z7) becomes logic 1,
Open the AND gate (31) and open the AND gate (31).
31), a logic O which is the input signal of the input branch line (7) of the transmission signal is output. On the other hand, NOR gate (29)
gate is closed and the output of the NOR gate (29) is logic O
Therefore, the output signal line (9) of the received signal, which is the output of the OR gate (33), has the same logic 0 as the input signal line (8) of the transmitted signal of the human output interface circuit (2A) on the B side.
signal is output. Next, as in signal state case 2 shown in Fig. 2, the human signal line (7) for both transmission signals,
Even if logic 1 is input to (8), signal state case 1
Similarly, since the outputs of drivers (3) and (4) are the same, no current flows through the detection resistor (21) and the comparator (
The outputs of 23) and (25) are both logic O.

Therefore, the gate of the NOR gate (27) opens and becomes logic 1, which is input to the AND gate (31). the result,
The gate of the AND gate (31) opens, and the output signal line (9) of the received signal, where the logic 1 is the output of the OR gate (9), receives the logic 1, which is the human input signal of the input signal line (7) of the transmission signal.
is output. This output also has the same logic as the human input signal of the human input signal line (8) of the transmission signal of the input/output interface circuit (2A) on the B side.

Next, as in signal state case 3 shown in Fig. 2, when logic 0 is applied to the human input signal line (7) of the transmission signal and logic 1 is input to the human input signal line (8) of the other transmission signal. ,
The output of the driver (3) becomes logic O, the output of the driver (4) becomes logic 1, a potential difference is generated between the driver (3) and the driver (4), current flows through the detection resistor (21), and the output of the driver (23) becomes logic 1. ), a positive potential difference is generated at the input of the comparator (25), and a negative potential difference is generated at the input of the comparator (25). As a result, the output of the comparator (23) becomes logic 1, the output of the comparator (25) becomes logic O, and N
The output of the OR gate (27) becomes logic O, the gate of the AND gate (31) closes, the gate of the NOR gate (29) opens, and the output of the comparator (25) is inverted by the NOR gate (29) to become logic O. 1 or is output to the output signal line (9) of the received signal. This output is also the human input signal line (8) of the input/output interface circuit (2A) on the B side.
) has the same logic as the input signal.

Next, as in signal state case 4 shown in Figure 2, logic 1 was manually input to the input signal line (7) of the transmission signal, and logic O was input to the input signal line (8) of the other transmission signal. case,
A potential difference opposite to the signal state case 3 is generated between the driver (3) and the driver (4), and a current flows in the detection resistor (21) in the opposite direction to the signal state case 3, and the comparator (23
) has a negative potential difference at the input of the comparator (25).
A positive potential difference is generated at the input of each. As a result,
The output of the comparator (23) becomes a logic O, the output of the comparator (25) becomes a logic 1, and the NOR gate (2
The output of 7) becomes a logic O, the gate of the AND gate (31) is closed, the gate of the NOR gate (29) is opened, the output of the comparator (25) is inverted by the NOR gate (29), and the logic O becomes the reception The signal is output to the signal output signal line (9). This output also has the same logic as the input signal of the input signal line (8) of the transmission signal of the input/output interface circuit (2A) on the B side. This operation is the same on the B-side human output interface circuit (2A) side. In this way, if the logic of the transmitted signals on both sides is the same, it will detect its own transmitted signal, and if it is different, it will detect the direction of the current and separate the other party's transmitted signal from the direction of the current. (13) Even if signals are transmitted simultaneously, each party can detect the other party's transmitted signals.

Note that in the above embodiment, it is not necessary to use the combination of logic elements used, but other combinations may be used as long as they are logically the same, and the same effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As explained above, this invention enables two signal input/output devices that mutually transmit digital signals to detect the other party's transmitted signal even if both transmit simultaneously through a pair of signal transmission paths. This has the advantage of being able to perform high-speed signal transmission at the output device.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a signal transmission system according to an embodiment of the present invention, Fig. 2 is a circuit diagram showing the operation of the circuit shown in Fig. 1, and Fig. 3 is a circuit diagram showing a conventional signal transmission system. figure. CIA), (2A) is the A side and B personal output interface circuit, (3), (4) is the driver,'
(7), (8) are the input signal lines of the transmission signal, (9),
(10) is the output signal line of the received signal, (13) is the signal transmission line, (21), (22) is the detection resistor, (23),
(24), (25), (26) are comparators, (27), (28), (29), (
30) is a NOR gate, (31) and (32) are AN
D gates, (33) and (34) are OR gates. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] A signal transmission path is arranged between each signal output section of the first and second signal input/output devices, and each signal input/output device has a signal output from its own signal output section and a signal output from the other party's signal output section. A signal synthesis section that synthesizes the output signals, a signal separation section that separates each output signal from the combined signal, removes its own output signal from these separated output signals, and inputs the output signal of the other party. A signal transmission method characterized by having a built-in signal removal section that outputs the signal to the section.