JPS639258A - Signal multiplex transmission system using start-stop synchronizing system - Google Patents

Abstract

PURPOSE:To improve the information transmission speed by setting a start bit informing signal start to a level different from the level of other signal so as to detect the signal start even without a pause signal. CONSTITUTION:In case of outputting a signal other than a start bit T from the terminal of a control circuit 2 at a sender side X connected to the base of a transistor (TR) 4 and outputting only the bit T from a terminal connected to the base of a TR 7, the level of the bit T appears at an output 10 as a voltage aV1 corresponding to a voltage V1 and appears at the output 10 as a level bV0 corresponding to the voltage V0 of the other signal. Since the level has the relation of aV1>bV0, the levels aV1, bV0 appearing at the input 13 of the reception side Y turn on a TR 15, but a TR18 is turned on by the signal level aV1 only under the existence of a Zener diode 16, and in obtaining an input signal from the input terminal connected to the TR 18, the control circuit 12 regards it as a start bit to read a signal inputted from the input terminal connected to TR 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a signal multiplex transmission system using a start-stop synchronization method.

[Conventional technology]

BACKGROUND ART Multiplex communication systems that transmit multiple types of data over the same line are conventionally known. Among these, it is necessary to achieve synchronization in time division multiplex communication, and one example of this is the start-stop synchronization method.

FIG. 4 shows an example of a general signal when the start-stop synchronization method is used. That is, signal part A uses 2 bytes of binary signals l and O, and signal part B similarly has an appropriate number of bytes.
A signal consisting of 12 signal parts of -L is transmitted, but in the start-stop synchronization method, a pause signal Z is issued so that the receiving side can determine the starting point of the signal, regardless of the data.

This is a constant level (“l” in this case) that continues for a period of one word (for example, 2 bytes) after the A-L signal.
By outputting this signal, the receiving side detects this pause signal Z and then reads the signal, assuming that the signal part A has started when "0" (start bit S) is received. It is something.

(Problems with the prior art) By transmitting the conventional start-stop synchronization method as described above, it is possible to multiplex and transmit data of different target items, but there is a problem that the pause signal may be confused with other signals. To avoid this, it is necessary to set the duration time to be longer than the "L" (or "0") duration time of other signals. That is,
Start bit “0” and end bit “1” in one word
”, if the signal is configured to include “1”, which is longer than one word
(or "0") does not exist in a normal transmission signal, making it possible to identify it as a pause signal.

However, since the pause signal makes up a large proportion of the total length of the signal, the transmission speed is limited, and the receiving side detects the pause signal and start bit, so it is not always transmitted. A problem arises in that it is necessary to monitor incoming signals, including whether they are pause signals and start bits. In particular, the signal portions A and B mentioned above.

−Start of each signal portion of L<If! ! :wari), 12 pause signals are required to send from A to L.

Furthermore, as shown in Japanese Patent Application Laid-Open No. 55-10,276, there is a device that improves the decline in information transmission efficiency by using a specific code structure, but this allows for transmission and In addition to requiring a lot of processing on the receiving side, it also requires the length of a specific code structure to replace the pause signal, although it has been shortened.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention is characterized in that the start bit that conveys the signal start is set to a different level from the levels of other signals.

[Effect]

On the receiving side, when a start bit with a level different from that of other signals is detected, the signal is read as a signal start.

〔Example〕

1 and 2 show one embodiment of the present invention.
The figure shows an example of a signal to be transmitted, and FIG. 2 shows an example of the configuration of a transmitting side and a corresponding receiving side.

In FIG. 1, A-L is a signal portion similar to that shown in FIG. 3 above. The transmission signal according to the present invention has no pause signal, and the level aV+ of the start bit T is made different from the level (0 or bv.) of other signals. In this case, aV
,>bVo, and on the receiving side, when this voltage of aV is input, the signal is read in the same way as when a conventional start bit is input.

This operation is possible, for example, by the configuration shown in FIG. That is, 12 sensors IA to II- are connected to a control circuit 2 on the transmitting side, and this control circuit 2 is provided with two output terminals. is connected to a PNP transistor 7 via an inverter 5 and a resistor 6. Transistor 4 has voltage ■ at its collector. The terminals of the emitter are connected through a resistor 8, and the emitter is grounded.

The transistor 7 has its emitter connected to a terminal with a voltage of 1, and its collector connected to the collector of the transistor 4 through a resistor 9, and this connection point is used as the output 10 of the transmitter side.

On the other hand, on the receiving side Y, there are displays, motors, and other actuators IIA corresponding to the above-mentioned sensors IA, IB, -1L.
, IIB, -11L are connected to the control circuit 12, and the base of the NPN transistor 15 is connected to the input 13 through which the output 10 of the receiving side X is input via a resistor 14. At the same time, an NPN transistor 18 is connected via a Zener diode 16 and a resistor 17. The emitter of the transistor 15 is grounded, and the collector is connected to one input terminal of the control circuit 12 and a power supply terminal via a resistor 19. The emitter of the transistor 18 is grounded, and the collector is connected to another input terminal of the control circuit 12 and to a power supply terminal via a resistor 20.

With the above configuration, signals other than the start bit T are output from the terminal connected to the base of the transistor 4 of the control circuit 2 on the transmitting side X, and only the start bit T is output from the terminal connected to the base of the transistor 7. If you output
The level of the start bit T is aV, which corresponds to Vl, and appears at the output 10, and the other signals are ■. bVo corresponding to
appears on the output 10 at a level of . Here, ay,>
bv.

Therefore, aV+ and b appearing at the input 13 of the receiving side Y
Both vo turns on the transistor 15, but the transistor 18 has aV due to the presence of the Zener diode 16.
is turned on only by the signal level of , and when the control circuit 12 receives an input signal from the input terminal connected to the transistor 18, it reads the signal input from the start bit input terminal. .

Incidentally, in addition to the signals shown in FIG. 1, a parity signal will actually be added, but is omitted here.

According to the present embodiment described above, it is possible to configure an asynchronous multiplex transmission system that does not require a pause signal.

FIG. 3 shows another embodiment of the invention, in which the transistor 21
By adding resistor 22, diodes 23 and 24, and making some connection changes, the configuration from the output terminal of the control circuit 2 on the transmitting side X to the output 10 on the transmitting side X shown in FIG. This is a modified example, and similar operations are possible.

The present invention makes the signal level of the start bit different from other signal levels, thereby eliminating the need for the conventional pause level, and the means for making the levels different and the means for detecting it are shown in FIG. It is not limited to the configuration shown in FIG.

In addition, in the above embodiment, the level of the start bit is set higher than the level of other signals, but the level of the start bit is set higher than the level of other signals.
If it is a binary signal of ``, then an appropriate value other than these values may be set as the level of the star 1 heavy voltage.For example, on the receiving side Y in FIG. It is also possible to treat it as a data signal, etc., and to treat it as a start bit when it is not conducting and the transistor 15 is in OIJ. Therefore, in that case, the level of the start bit can be set to "1" of other signals. It may be set to an appropriate value between "0".

〔Effect of the invention〕

According to the present invention, the start of a signal can be detected even without a pause signal, thereby improving the information transmission speed, and on the receiving side, when a start bit with a different level is input, it is treated as the start of a signal. Therefore, it is possible to obtain the effect that the start bit can be easily distinguished from other signals.

[Brief explanation of drawings]

1 and 2 show one embodiment of the present invention, FIG. 1 is a diagram showing an example of a transmitted signal, FIG. 2 is a diagram showing the configuration of the transmitting side and receiving side, and FIG. 3 is a diagram showing an example of the transmitted signal. Another embodiment of the present invention is shown, and FIG. 4 is a diagram showing an example of a modification of the configuration of the transmitting side in FIG. 2, and FIG. 4 is a diagram showing an example of a signal that appears when the conventional start-stop synchronization method is used. ■A~IL-sensor 2-transmission side control circuit 3, 6,
8,9,14,17,19,20.22--1 resistance 4,
7, 15, 18, 2t-) Ranjimeter 5-Inverter 10-Output on the sending side 11-Actuator 12-Control circuit on the receiving side 13-Input on the receiving side
16- Zener diode x - transmitting side
Y - Receiving side A-L - Signal parts other than start bit - Start bit

Claims (1)

[Claims] In a signal multiplex transmission system using the start-stop synchronization method,
A signal multiplex transmission system using a start-stop synchronization method, characterized in that a start bit that conveys the start of a signal is set at a level different from the level of other signals.