JPS5837599B2 - Jikanhabadensou Cairo - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a time width transmission circuit that transmits a time width signal through a two-wire transmission line and converts it into a pulse width.

FIG. 1 is a circuit diagram showing an example of a conventional time width transmission circuit, and shows .about.Φ conversion using a pulse width modulation method.

In FIG. 1, 1 is an A/D converter, 2 is a pulse width conversion circuit, and the A/D converter 1 has a reference voltage source Er and a resistor Ri.
, Rr, a switch SW1, a capacitor C5, an amplifier A1, a comparator COMP, etc., and the pulse width conversion circuit 2 is composed of a flip-flop circuit OFF, etc.

The switch SW of the A/D converter 1 is connected to the output terminal Q of the flip-flop circuit FF of the pulse width conversion circuit 2 through the transmission line pair L1, and the comparator COMP is connected to the reset terminal R of the flip-flop circuit FF and the transmission line pair L2. connected with.

The transmission line pair L1 is for transmitting a starting signal for starting the A/D converter 1, and the output signal from the output terminal Q of the flip-flop circuit FF is transmitted, and this output signal closes the switch SW. do.

The transmission line pair L2 transmits the operation end signal output from the comparator COMP of the A/D converter 1 to the reset terminal H of the flip-flop circuit FF of the pulse width conversion circuit 2 as a reset signal.

In such a configuration, when the start signal START is applied to the set terminal S of the flip-flop circuit FF, the switch SW is closed, and after a predetermined period of time, an operation end signal is transmitted to the reset terminal R of the flip-flop circuit FF.

As a result, the operating time of the A/D converter 1 is converted into a pulse width signal PW and outputted from the flip-flop circuit FF.

In this way, in the conventional time width transmission circuit, the transmission lines Ll,
Since L2 is used, four or three wires will be connected between the A/D converter 1 and the pulse width conversion circuit 2.
The disadvantage is that the cost of the transmission line is high, and when used as an input device for an electronic computer, the connection part becomes loose.

In order to solve these drawbacks, the present invention realizes a time width transmission circuit using a two-wire transmission line, and will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of the present invention,
Two-wire transmission line 3 consisting of two transmission lines 31 and 32
, a signal system 4 connected to one end of this two-wire transmission line 3,
Pulse width conversion system 5 connected to the other end of the two-wire transmission line 3
It consists of

Note that the A/A shown in FIG.
A time width signal generation circuit 6 such as the D converter 1 is arranged, and in the time width transmission circuit according to the present invention, the operation time of the time width signal generation circuit 6 is used as a time width signal to generate pulses on the two-wire transmission line 3. It is transmitted to a width conversion system 5 and converted into a pulse width signal.

The signal coupling system 4 is composed of a first coupling circuit 41 and a second coupling circuit 42 that can flow signals in a fixed direction. transmission line 31. 32? One end 31a
, 32a in parallel.

Further, these coupling circuits 41 and 42 are for transmitting and receiving signals with the time width signal generation circuit 6, and the coupling circuit 41 transmits the signal of the two-wire transmission line 3 to the time width signal generation circuit 6. , the coupling circuit 42 transmits the signal from the time width signal generation circuit 6 to the two-wire transmission line 3.

The pulse width conversion system 5 includes a transmission signal detection circuit 51 and a line system m
It is composed of a circuit 52, a flip-flop circuit 53,
One input/output terminal 52a of the line control circuit 52 is connected to the end 3lb of one can feeding line 31 via the transmission signal detection circuit 51 as described above, and the other input/output terminal 52b
is connected to the end 32b of the other transmission line 32.

The flip-flop circuit 53 is equipped with a set terminal 5353a, a reset terminal 53b, and an output terminal 53c.A start signal is input from the outside to the set terminal 53a, a detection signal from the transmission signal detection circuit 51 is input to the reset terminal 53b, and an output terminal 53c outputs a pulse width signal to the line control circuit 52 and pulse width signal output terminal 7.

Regarding the operation of the time width transmission circuit having such a configuration, the third
This will be explained using the time chart shown in the figure.

First, the activation signal S1 shown in FIG. 3a is applied to the set terminal 53a of the flip-flop circuit 53.

This activation signal S1 causes the flip-flop circuit 53 to
+” level to II I I+ level,
From the output terminal 53c as shown in FIG. 3b! An output signal S2 at the I I It level is output.

The line control circuit 52 controls the input/output terminal 52 to transmit the signal to the two-wire transmission line 3 using the signal S2 at the 1'11 level.
The state is changed from the state a→coupling circuit 41→input/output terminal 52b to the state of input/output terminal 52b→coupling circuit 42→input/output terminal 52a.

The signal S3 shown in FIG. 3e is a signal flowing to the coupling circuit 41, and the signal S4 shown in FIG. 3d is a signal flowing to the coupling circuit 42. No signal S3 flows through the circuit 41 II O N
changes from I1 to I+OFF1', and at the same time the coupling circuit 4
2 changes from the "OFF" state to the "ON possible" state of 1.

Note that the "ON enabled 1" state means that the line control circuit 52 sends the signal S from the coupling circuit 42 to the input/output terminal 52a.
4 is set to be able to flow.

When the signal S3 flowing through the coupling circuit 41 changes to "OFF", the coupling circuit 41? The starting signal S5 shown in FIG. 3f is sent to the time width signal generating circuit 6, and the time width signal generating circuit 6 is activated.

After a predetermined period of time has elapsed, the time width signal generating circuit 6 outputs the operation end signal S6 shown in FIG.
transmission line 3.

Here, as described above, the line control circuit 52 is connected to the coupling circuit 42.
Since the state is set such that the signal S4 can flow from the input/output terminal 52a toward the input/output terminal 52a, the operation end signal S6 is transmitted as the signal S4 from the coupling circuit 42 toward the input/output terminal 52a.

The transmission signal detection circuit 51 detects the rise of the signal S4 and sends it to the reset terminal 53b of the flip-flop circuit 53 as a reset signal S7 shown in FIG. 3C.

When the reset signal S7 is input, the output signal S2 of the flip-flop circuit 53 changes from the 1111 level to II I+
The line control circuit 52 is reset to the II level.
Depending on the I+ level, the direction of signal transmission to the two-wire transmission line 3 is changed from input/output terminal 52b to coupling circuit 42 to input/output terminal 5.
The state of input/output terminal 52a→coupling circuit 41→input/output terminal 52b is switched from the state of 2a, and the signal s3 starts to flow through the coupling circuit 41, and the signal S3 becomes "OFF" or "L+".
Become IONI+.

At the same time, the state of the coupling circuit 42 changes from "ON" to 11 o p
p Changes to I+.

As a result, the output signal S2 of the flip-flop circuit 53 is transmitted from the pulse width signal output terminal 7 to the time width signal generation circuit 6.
It is output as a pulse width signal corresponding to the operating time of .

FIG. 4 is a circuit diagram showing an example of a specific circuit in the block diagram of FIG. The coupling circuit 42 includes a diode D2 and a phototransistor TR in a direction opposite to that of the light emitting diode D1 of the coupling circuit 41.
Two series circuits are connected in parallel to the light emitting diode D1.

Further, the time width signal generation circuit 6 includes a phototransistor TR so as to face the light emitting diode D1 of the coupling circuit 41.
1 is arranged, and the phototransistor TR of the coupling circuit 42
A light emitting diode D3 is arranged to face the two-wire transmission line 3 and the time width signal generating circuit 6 are insulatedly coupled by optical coupling.

What about the transmission signal detection circuit 51? The operation completion signal S6 from the time width signal generation circuit 6 is sent to the flip-flop circuit 53 as a reset signal S7 via the transistor TR3.

As the line control circuit 52, an inverter circuit INVI,
INV2 and INV3 are combined, and an inverted output signal of the output signal S2 of the flip-flop circuit 53 is outputted to the input/output terminal 52a via the inverter circuit INV1, and the inverter circuits INV2 and INV3 are connected to the input/output terminal 52b.
The output signal s of the flip-flop circuit 53 via NV3
A signal with the same polarity as 2 is output.

When considering the above-mentioned A/D converter 1 shown in FIG. The operation end signal of the comparator COMP is sent to the transmission signal detection circuit 51 via the coupling circuit 42,
The output terminal 53c of the flip-flop circuit 53 has an A/D
A pulse width signal corresponding to the converted digital signal is output.

FIG. 5 is a block diagram showing another embodiment of the present invention, in which parts having the same functions as the pulse width transmission circuit shown in the block diagram of FIG. 2 are given the same numbers.

In FIG. 5, the signal coupling system 4 includes a coupling circuit 43 and a coupling circuit 44 that can transmit signals in a fixed direction and are connected in the forward direction, and the signal is transmitted from the coupling circuit 43 to the time width signal generation circuit 6. , from the time width signal generation circuit 6 to the coupling circuit 4
4 to the two-wire transmission line 3.

The coupling circuit 44 also has a switch function, and normally closes the loop of the signal coupling system 4, the two-wire transmission line 3, and the pulse width conversion system 5, but the signal from the time width signal generation circuit 6 is When an output is generated, the contact is opened and the loop is opened.

The line control circuit 54 constituting the pulse width conversion system 5 is configured to send out only a signal in one direction corresponding to the directionality of the signal coupling system 4, and the signal is sent out based on the output signal of the flip-flop circuit 53. controlled.

6 is a time chart for explaining the operation of FIG. 5, in which the set terminal 53 of the flip-flop circuit 53
When the starting signal S1 shown in Fig. 6a is applied to a, Fig. 6b
The output signal S2 of the flip-flop circuit 53 shown in FIG.
1'' level to the °T1 level, and is output from the output terminal 53c.

The line control circuit 54 receives a signal S2 of II I I+ level.
When input, the line control circuit 54 sends a signal in a predetermined direction.
For example, the signal S8 shown in FIG.
is transmitted, and the starting signal S5 shown in FIG. 6e for starting the time width signal generating circuit 6 is outputted from the coupling circuit 43.

After a predetermined period of time has elapsed, the time width signal generating circuit 6 generates an operation end signal S6 shown in FIG.

Here, as described above, the coupling circuit 44 has a function of opening the switch contact when the operation end signal S6 is output, so the loop consisting of the signal detection system, the two-wire transmission line, and the pulse width conversion system is not opened. It will be done.

The transmission signal detection circuit 51 connected to the transmission line 31 detects the open state of the loop and detects the flip-flop circuit 5.
The reset signal Sγ shown in FIG. 6C is output to the reset terminal 53b of No. 3.

When the reset signal S7 is input, the output of the flip-flop circuit 53 is reset to the 1111 level or the If01' level, and the signal S8 from the line control circuit 54 shown in FIG. From 7 onwards, the output signal S2 of the flip-flop circuit 53 is output as a pulse width signal corresponding to the operating time of the time width signal generating circuit 6.

The switch in coupling circuit 44 then returns to close the loop.

With this configuration, a time width signal generated from timing signals generated at two separate locations can be transmitted through a two-wire transmission line.

In addition, in the present invention, the digital signal is transmitted to the two-wire transmission line after A/D conversion near the time width signal generation circuit, so the S/N ratio is excellent, and the signal is connected to the time width signal generation circuit. When coupling signals with the system, electrical insulation can be achieved by optical coupling or the like.

Furthermore, by setting the transmission mode to current mode, the measurement accuracy of the pulse width can be improved.

As explained above, according to the present invention, it is possible to transmit a time width signal based on a timing signal generated between two points separated by a two-wire transmission line, so it is possible to reduce the cost of the transmission line, and it is economical. It is also very effective.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an example of a conventional time width transmission circuit, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a time chart explaining the operation of Fig. 2, and Fig. 4 2 is a circuit diagram showing a specific circuit example of FIG. 2, FIG. 5 is a block diagram showing another embodiment of the present invention, and FIG. 6 is a time chart explaining the operation of FIG. 5. 3...2-wire transmission line, 31, 32...
・Transmission line, 4...Signal coupling system, 41, 42
, 43, 44...Coupling circuit, 5...Pulse width measurement system, 51...Transmission signal detection circuit, 5
2...Line control circuit, 53...Flip-flop circuit, 54...Line control circuit,
6... Circuit to be measured, 7... Pulse width signal output terminal.

Claims (1)

[Claims] 1. A signal coupling system for exchanging signals with a time width signal generation circuit is connected to one end of the two-wire transmission line, and the other end is connected to a signal coupling system for transmitting and receiving signals to and from a time width signal generation circuit, and the other end is connected to a signal coupling system for transmitting and receiving signals to and from a time width signal generation circuit. In a time width transmission circuit connected to a pulse width conversion system for detecting a pulse width, the signal coupling system is composed of a first coupling circuit and a second coupling circuit connected in parallel with different directions, and A pulse width conversion system includes a line control circuit, a transmission signal detection circuit, and a flip-flop circuit for selectively outputting a signal corresponding to the directionality of each of the coupling circuits, and a set signal is applied to the flip-flop circuit of the pulse width conversion system. As a result, the time width signal generation circuit is activated via the line control circuit and the first coupling circuit, and after a predetermined time, the transmission signal is detected from the time width signal generation circuit via the second coupling circuit. An operation end signal is sent to the circuit, and this operation end signal is applied from the transmission signal detection circuit to the flip-flop circuit as a reset signal, and the operation time of the time width signal generation circuit is outputted from the flip-flop circuit as a pulse width signal. A time width transmission circuit featuring: 2. A signal coupling system for transmitting and receiving signals with a time width signal generation circuit is connected to one end of the two-wire transmission line, and a pulse width is connected to the other end to detect the operating time of the time width signal generation circuit as a pulse width. In the time width transmission circuit to which the conversion system is connected, the signal coupling system is connected in series in the forward direction.
a coupling circuit and a second coupling circuit, and the pulse width conversion system is composed of a line II}IN circuit that outputs a signal corresponding to the directionality of the coupling circuit, a transmission signal detection circuit, and a flip-flop circuit, By applying a set signal to the flip-flop circuit of the pulse width conversion system, the time width signal generation circuit is activated via the line control circuit and the first coupling circuit, and after a predetermined time, the time width signal generation circuit is activated. An operation end signal is sent to the second coupling circuit to cut off the two-wire transmission line, a reset signal is applied from the transmission signal detection circuit to the flip-flop circuit, and the operation time of the time width signal generation circuit is changed to the flip-flop circuit. A time width transmission circuit characterized in that the circuit outputs a pulse width signal.