JPS5879355A - Signal transmission device - Google Patents

Abstract

PURPOSE:To speed up the transmission of digital signals, by providing a signal injection circuit to the transmitter, and a reception circuit using a photocoupler for the receiver, and using a signal line between a transmitter and a receiver without polarity. CONSTITUTION:A transmitter T consists of a signal forming circuit 11 and a signal injection circuit 19, and when an output of the circuit 11 is of positive polarity, a transistor TR is activated and a digital signal is outputted between output terminals 13 and 14 of the transmitter T. The signal between the terminals 13 and 14 is transmitted to input terminals 15 and 16 of a receiver R via signal lines l1, l2 without polarity. The signal from the terminals 15, 16 is applied to a reception circuit 20 provided with photocouplers PC1, PC2, the output of the photocoupler PC1 or the PC2 is applied to a signal discriminating circuit 18 to discriminate the digital signal transmitted from the transmitter T. The signal lines l1, l2 are formed without polarity, allowing to make the installation easy and to speed up the signal transmission speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal transmission device that transmits digital signals between a plurality of transmitters and receivers using two signal lines.

In FIG. 1, a system connection example of a signal transmission device including a transmitter and a receiver is shown as a first factor.

Tt, Tts..., ■ is the transmitter, Ru-R goose,
・・・・・・eR.

llm-Is-lx is a signal line. In addition, 2
A two-core signal line may be used for the real signal l1ls 1m. Note that below %<T is used for the transmitter and R is used for the receiver when it is not necessary to express them individually.

Generally, in order to transmit a digital signal from a transmitter T to a receiver R, the digital signal is converted into a serial signal depending on the presence or absence of a voltage (or electric current R) before being transmitted. In this case, the two signals 11m1tel proverb have polarities for the outgoing route and the return route, which has the disadvantage that work to match the polarity is required when installing the signal 1al*lx.

Traditionally, the two signal lines 1* and 1m are non-polar, and the transmitter T converts the digital signal into a high-frequency signal and sends it out, and the receiver R demodulates the high-frequency signal into a digital signal. was.

As an example of using high frequency signals and using two signal lines 11 m 1 g with no polarity, one transmitter T and one transmitter 1
A boot diagram for signal transmission between two receivers 3 is shown in FIG.

In FIG. 2, the transmitter ■ consists of a signal generation circuit 11 and a modulation circuit 12, and the output side of the modulation circuit 12 is the output terminal 1.
s, 14. The receiver R is composed of a demodulation circuit 11 and a signal discrimination circuit 18, and the input side of the demodulation circuit 110 is connected to an input terminal 15. l1ik is connected. The output terminals 13 and 14 of the transmitter ■ and the input terminals IS and 11i of the receiver R are connected by two signals @J and Is.

Next, the operation will be explained. Signal generation circuit 1 of transmitter T
1 creates a digital signal in serial form.

It is passed to the modulation circuit 12. It is converted into a high frequency signal by the modulation circuit 12 and outputted from the output terminal IS, 14.

On the other hand, in the receiver R, the high frequency signal inputted from the input terminal 15, 1@ is converted into a digital signal by the demodulation circuit 11 and passed to the signal discrimination circuit 18. Although the high frequency signal has positive and negative polarities, the demodulation circuit 1T performs half-wave rectification or full-wave rectification to convert the high frequency signal into a digital signal, so the two signal lines 11.1. can be used as non-polar.

The conventional signal transmission device transmits two signals @t, as described above.
, t, have no polarity, the digital signal is converted into a high frequency signal and transmitted. For this reason, it has the disadvantage that the transmission speed is slower than when directly transmitting digital signals.

This invention was made to eliminate the above-mentioned drawbacks, and aims to provide a signal transmission device that can directly transmit digital signals, speed up signal transmission, and use signal lines as non-polar. .

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 3, the transmitter T is composed of a signal generation circuit 11 and a signal injection circuit 19. Further, the signal injection circuit 1s is composed of resistors R, , Rt and a transistor TR.

The output of the signal generating circuit 11 is connected to the base of the transistor TR via a resistor R1. The pace of transistor TR is connected to the ground terminal (common power supply terminal) through resistor R8.
K-connected. Further, the ground terminal is output to the output terminal 14. The collector of transistor TR is connected to the positive power supply (V
c*), and its emitter is connected to the output terminal 13.

The receiver R is composed of a signal receiving circuit 20 and a signal discriminating circuit 18. The signal receiving circuit 20 is a resistor @Rs −R4,
and photocouplers PCx and PCs. The input terminal 15 of the receiver R is connected to the photocoupler P via a resistor R3.
It is connected to the cand side of the primary side diode of CI and the 7th node side of the primary side diode of photocoupler PC8. Photocoupler PCs
, Pct, the collectors of the secondary transistors are coupled together, and the emitters are coupled together and connected to the signal discrimination circuit 11. Photocoupler PCt-P
The collector connection point of the secondary side transistor of C is the resistor R.
Positive voltage (Vc*) K is connected at 4, photocoupler PCx,
The PCs are wired OR connected. The output terminal 13.14 of the transmitter T is connected to the input terminal 15.11iK of the receiver R by a signal line 11 e 11 . The output terminal ISK of the transmitter T receives a positive voltage (
VCI) "Logic 1' or no voltage 1 logic 0" is coded and output.

In the example of the third cause, the output terminal 13' is connected to the input terminal 15, so when a positive voltage (Yes) Ill'' is applied to the input terminal 15, the primary side meiode Ktl1m of the photocoupler Pew flows, Input terminal 15 is no voltage 1
In the case of logic Ilθ'', the photocoupler PCs operates so that the primary side diode of the photocoupler Pct becomes non-conductive, and the signal can be received.

In this case, the photocoupler Pct does not operate and signal reception is not involved. If the connection between the output terminal 13.14 of the transmitter T and the input terminal 15.111 of the receiver R is reversed to the above,
That is, the output terminal 13 is the input terminal 16K, and the output terminal 14 is the input terminal 16K.
is connected to the input terminal 15, the digital signal output to the output terminal 13 of the transmitter T is input to the input terminal 18 of the receiver R, and the photocoupler Pct operates to receive the signal. In this case, the photocoupler Pc1 does not operate and is not involved in signal reception.

In addition, in the above, since the operation explanation is simple, only one sending aS and one sending aS are used.
Although the explanation has been made using one receiver, it is obvious that a system using multiple transmitters and multiple receivers as shown in FIG. 1 can also be applied.

As described above, the signal transmission device of the present invention is as follows.

It has two signal wires that are interlocked to transmit signals between the transmitter and receiver, and the signal wires are non-polar and can transmit digital signals, making it easy to install signal wires and high-speed. There is an advantage that a signal transmission device capable of signal transmission can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of system connection of a signal transmission device, FIG. 92 is a block diagram showing a conventional signal transmission device, and FIG. 3 is a block diagram showing a block diagram of a signal transmission device of the present invention. In the figure, ■ is the transmitter, and R is the receiver.
11 is a signal generation circuit, 13.14 is an output terminal, and 15. is a signal line. lli is the input terminal, 1$ is the signal discrimination circuit, 1s
is a signal injection circuit 11M, 20 is a signal receiving circuit, R3-R4 are resistors, TR is a transistor, and PCI-PCs is a photocoupler. Note that the same reference numerals in the figures indicate the same or corresponding parts. Figure 1

Claims (1)

[Claims] A signal transmission device that performs signal transmission between a transmitter and a receiver using two signal lines, the transmitter being equipped with a signal injection circuit that outputs a digital signal consisting of the presence or absence of a positive voltage; A signal receiving circuit is provided with two photocouplers, the primary side diodes of these two photocouplers are connected in antiparallel and coupled to the signal t, and the secondary side transistors of the two photocouplers are connected in parallel. A signal transmission device that is specially designed to be equipped.