JP2002314382A - Pulse generator circuit, method for preventing its malfunction and communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a pulse caused by a malfunction from being outputted to a circuit of a subsequent stage without performing ground reinforcement or noise cutoff measures in a pulse generator circuit. SOLUTION: A monostable multivibrator circuit 3 outputs a signal of a prescribed pulse width at needed timing, and a differentiating circuit 4 inputs an output signal of the monostable multivibrator circuit 3, differentiates the output signal and outputs the differentiated output signal. A signal outputted from the differentiating circuit 4 is inputted to a monostable multivibrator circuit 7, and when noise occurs, the multivibrator circuit 7 operates. An AND circuit 8 ANDs signals outputted from the monostable multivibrator circuits 3 and 7 and outputs the results.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse generating circuit, a method for preventing malfunction thereof, and a communication apparatus, and more particularly to a method for transmitting a signal of a predetermined pulse width using a monostable multivibrator (hereinafter, referred to as a monomulti). The present invention relates to a pulse generating circuit to output, a malfunction prevention method thereof, and a communication device.

[0002]

2. Description of the Related Art Conventionally, when a signal having a predetermined pulse width is generated by using a rising or falling edge of a signal as a trigger, for example, as shown in FIG. I was In FIG. 6, the mono multi 3 connects the input terminal A to the ground, and the input terminal B connects an input signal serving as a trigger signal for operating the mono multi 3. The resistor 1 and the capacitor 2 are connected to the monomulti 3 and determine the pulse width of a signal to be output when the monomulti 3 is triggered. At this time, in an environment where no noise or the like occurs, the pulse generation circuit operates normally.

[0003]

In the conventional pulse generating circuit using the above-mentioned mono-multi, when noise (noise) such as static electricity is generated, neither measures to strengthen the ground nor measures to cut off the noise are taken. However, the ground becomes unstable due to the influence of noise, and a trigger is activated inside the mono-multi. As a result, even if there is no signal at the input, a malfunction occurs easily and a pulse is output. Therefore, there is a problem that a pulse is output at a timing that is not originally required. SUMMARY OF THE INVENTION An object of the present invention is to provide a pulse generation circuit capable of preventing a pulse due to a malfunction from being output to a subsequent circuit without taking measures for ground reinforcement and noise cutoff, a malfunction prevention method thereof, and a communication device. It is in.

[0004]

A pulse generating circuit according to the present invention comprises a first monostable multivibrator for outputting a signal having a predetermined pulse width at a required timing, and a second monostable multivibrator for operating when noise occurs. And a pulse signal output when the first monostable multivibrator malfunctions due to noise is canceled by a pulse signal output from the second monostable multivibrator.

Further, the pulse generating circuit of the present invention outputs a signal having a predetermined pulse width at a required timing.
A monostable multivibrator, a differentiating circuit that inputs and differentiates an output signal of the first monostable multivibrator, and a differential circuit that operates when a noise is generated using the signal output from the differential circuit as an input. 2 monostable multivibrators, and a logical product circuit for performing a logical product of the signals output from the first and second monostable multivibrators and outputting the result of the logical product, and Logical AND circuit.

A communication device according to the present invention includes a first monostable multivibrator that outputs a signal having a predetermined pulse width at a required timing, and a second monostable multivibrator that operates when noise occurs.
And a pulse signal output when the first monostable multivibrator malfunctions due to noise is canceled by a pulse signal output from the second monostable multivibrator. It has a pulse generation circuit. Further, the communication device of the present invention inputs a first monostable multivibrator that outputs a signal of a predetermined pulse width at a required timing, and outputs and differentiates an output signal of the first monostable multivibrator. A differentiating circuit, a second monostable multivibrator that operates when a noise is generated by receiving a signal output from the differentiating circuit as an input, and a logic of a signal output from the first and second monostable multivibrators There is provided a pulse generation circuit including an AND circuit or a NAND circuit that takes a product and outputs the result. The noise is noise generated by static electricity.

According to the method of preventing a malfunction in the pulse generation circuit of the present invention, a first signal having a required pulse width is output from a first monostable multivibrator, and the first signal is input and differentiated to obtain a signal having a predetermined width. The second monostable multivibrator is operated to output a second signal when noise is generated by inputting the pulse having the predetermined width and outputting the second signal.
And the second signal is ANDed and the result is output, and the AND may be a negative AND.
The noise is noise generated by static electricity.

According to the present invention, when noise due to static electricity is generated, a signal output from the monomulti for normal pulse width output due to malfunction is masked by a signal output from the monomulti for detecting static electricity, ie, By canceling, a pulse due to a malfunction can be prevented from being output to the subsequent circuit.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, a pulse generating circuit according to the present invention connects a resistor 1 and a capacitor 2 for determining a pulse width, inputs an input signal serving as a trigger, and outputs a signal having a required pulse width. A monomulti 3 for outputting a regular pulse width, a differentiating circuit 4 for differentiating an output signal of the monomulti 3, a resistor 5 and a capacitor 6 for determining a pulse width are connected to each other, and And the multi-function 7 for detecting static electricity that operates when noise due to static electricity is input, and the logical product of the signals output from the mono-multi 3 and the mono-multi 7 and the logical product that outputs the result (AND) circuit 8.

A communication device which has a pulse generating circuit for outputting a signal of a pulse width determined by a mono-multi, and which is installed in a place where static electricity is frequently generated due to intense human traffic, concrete devices The names include a carrier relay device, a program transmission control device, and the like. A carrier relay device is a communication device for transmitting and receiving information on current flowing in a transmission line to prevent a generator or a transformer from being damaged due to a transmission line accident.A program transmission control device controls a program. This is a device that superimposes a control signal for performing the superimposition on a video signal or an audio signal and detects the superimposed signal.
Note that the pulse generation circuit of the present invention can be applied not only to the above-described device but also to a general communication device.

In FIG. 1, a mono multi 3 has an input terminal A
Is connected to the ground, and an input terminal B is connected to an input signal serving as a trigger signal for operating the mono multi 3. The resistor 1 and the capacitor 2 are connected to the mono multi 3 and determine the pulse width of a signal to be output when the mono multi 3 is triggered. The signal output from the mono-multi 3 is input to the differentiating circuit 4, and the differentiating circuit 4 differentiates and outputs the input signal. The signal output from the differentiating circuit 4 is connected to the input terminal B of the mono-multi 7, and the input signal is connected to the input terminal A of the mono-multi 7. The monomulti 7 outputs a signal having a pulse width determined by the resistor 5 and the capacitor 6 according to the conditions of the input signals at the input terminals A and B. The signal output from the mono-multi 7 is connected to the AND circuit 8. A
The ND circuit 8 takes the logical product of the output signal from the mono-multi 7 and the output signal from the mono-multi 3, and outputs the result.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIGS. The mono-multi in this case is of the retrigger type for convenience. The trigger is applied to the mono-multi when the signal at the input terminal A is LOW and the signal at the input terminal B rises, and when the signal at the input terminal B is HI and the signal at the input terminal A falls. .

First, the operation in the case where the noise is not affected by static electricity will be described. The input signal to the input terminal B of the mono-multi 3 is normally LOW, and changes to HI as shown in S1 of FIG. 2 when a signal having a required pulse width is to be output. Mono multi 3 has this input signal HI
, A signal which becomes HI for the pulse width determined by the resistor 1 and the capacitor 2 is output Q
(S2 in FIG. 2). The signal output from the output Q is input to the differentiating circuit 4. Since the differentiating circuit 4 differentiates and outputs the input signal, it outputs a signal that becomes HI only for a very short width (S3 in FIG. 2).

The output signal of the differentiating circuit 4 is connected to the input terminal B of the monomulti 7, and the same signal as the input signal of the monomulti 3 is connected to the input terminal A. Therefore, when the input signal to the input terminal B is HI, the input signal to the input terminal A is also HI. That is, the trigger is not applied to the mono multi 7 and the pulse signal having the determined width is not output from the output Q bar (S4 in FIG. 2).

The AND circuit 8 outputs a logical product of the output signal from the mono-multi 3 and the output signal from the mono-multi 7. Since the signal from the mono multi 7 is always HI, A
The signal from the mono multi 3 is output as it is from the ND circuit 8 (S5 in FIG. 2).

Next, a description will be given of an operation in the case where noise due to static electricity occurs and the mono multi 3 malfunctions.

When noise due to static electricity is generated, the ground becomes unstable due to the influence. As a result, a trigger is activated inside the mono-multi 3, and a signal that becomes HI from the output Q by the pulse width determined by the resistor 1 and the capacitor 2 is output (S in FIG. 3).
7). At this time, since the input has no trigger signal, it remains LOW (S6 in FIG. 3). Differentiator 4 is mono-multi 3
In order to differentiate the signal from, a signal that becomes HI only for a very short width is output (S8 in FIG. 3).

On the other hand, since the same input signal as that of the monomulti 3 is input to the input terminal A of the monomulti 7, it remains LOW. Since the signal from the differentiating circuit 4 is input to the input terminal B, the monomulti 7 operates by using the signal as a trigger, and outputs a signal which becomes LOW by the width determined by the resistor 5 and the capacitor 6 from the output Q bar. (S9 in FIG. 3). At this time, the value of the pulse width set by the resistor 1 and the capacitor 2 is D, the resistor 5 and the capacitor 6
Is set to E, and D <E is satisfied. Therefore, an HI signal having a pulse width D is output from the output Q of the monomulti 3, and a LOW signal having a pulse width E is output from the output Q bar of the monomulti 7.

The AND circuit 8 receives the HI signal having the pulse width D output from the monomulti 3 and the LOW signal having the pulse width E output from the monomulti 7 and outputs a logical product of them. A LOW signal is output (S10 in FIG. 3). In other words, even if noise due to static electricity occurs, the output of the mono-multi 7 cancels the pulse of the mono-multi 3, so that an erroneous pulse is not output to the subsequent circuit.

Next, the operation in the case where noise caused by static electricity occurs and the mono-multi 3 and the mono-multi 7 simultaneously malfunction will be described.

If the mono-multi 3 and the mono-multi 7 malfunction at the same time, the mono-multi 3 outputs a signal (S11 in FIG. 4) which becomes HI for the pulse width determined by the resistor 1 and the capacitor 2. Outputs a signal (S12 in FIG. 4) which becomes LOW by the pulse width determined by the resistor 5 and the capacitor 6. Therefore, the AND circuit 8 is canceled by the LOW signal output from the mono-multi 7, and the output from the AND circuit 8 is L
An OW signal (S13 in FIG. 4) is output. That is, even if the monomultis 3 and 7 simultaneously malfunction due to noise caused by static electricity, an erroneous pulse is not output to the subsequent circuit.

The present invention is not limited to the above-described circuit example. For example, as shown in FIG. 5, even if a NAND circuit 9 is used instead of the AND circuit 8 as the final gate, the same applies. The effect of can be obtained. The pulse generation circuit in this case is exactly the same as the configuration shown in FIG.

Referring to FIG. 5, the operation is as follows.
The operation up to the output of the mono-multi 3 and the mono-multi 7 is the same as the operation of FIG. 1, and the logic of the signal output from the final gate is opposite to that of FIG. Specifically, when there is no trigger signal in the mono multi 3 or when noise due to static electricity occurs, a HI level signal is output. When a trigger signal is input to the mono multi 3, a signal that becomes LOW by a pulse width determined by the resistor 1 and the capacitor 2 is output.

[0025]

As described above, according to the present invention, a mono-multi that outputs a signal at a required timing without taking measures against ground reinforcement and noise cut-off provides a pulse signal output due to a malfunction of noise. By canceling with a pulse output from the noise detection mono-multi, it is possible to prevent a pulse due to a malfunction from being output to a subsequent circuit.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a signal generation circuit of the present invention.

FIG. 2 is a waveform chart for explaining the operation of the embodiment of the present invention.

FIG. 3 is a waveform chart for explaining the operation of the embodiment of the present invention.

FIG. 4 is a waveform chart for explaining the operation of the exemplary embodiment of the present invention.

FIG. 5 shows A in the embodiment of the signal generation circuit of the present invention.
FIG. 3 is a diagram illustrating a case where an ND circuit is replaced with a NAND circuit.

FIG. 6 is a diagram illustrating an example of a conventional signal generation circuit.

[Explanation of symbols]

 1,5 Resistance 2,6 Capacitor 3,7 Mono-multi 4 Differentiation circuit 8 AND circuit 9 NAND circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J039 AB04 BB20 FF02 KK03 KK10 MM08 NN01 5J043 AA06 AA23 BB04 CC03 DD05 DD07 DD11 EE00 FF04 NN01 PP01 PP02 PP02

Claims (8)

[Claims] 1. A first monostable multivibrator for outputting a signal having a predetermined pulse width at a required timing;
A second monostable multivibrator that operates when noise is generated, and outputs a pulse signal output when the first monostable multivibrator malfunctions due to noise from the second monostable multivibrator. A pulse generating circuit configured to be canceled by a pulse signal generated. 2. A first monostable multivibrator for outputting a signal having a predetermined pulse width at a required timing;
A differentiating circuit for inputting and differentiating an output signal of the first monostable multivibrator, and a second monostable multivibrator operating when a signal generated from the differentiating circuit is input and noise occurs. , The first and second
And a logical product circuit for calculating the logical product of the signals output from the monostable multivibrators and outputting the logical product. 3. The pulse generation circuit according to claim 2, wherein said AND circuit is a NAND circuit. 4. A communication device comprising the pulse generation circuit according to claim 1, 2 or 3. 5. A first signal having a required pulse width is output from a first monostable multivibrator, and the first signal is input and differentiated to output a pulse having a predetermined width. And when a noise is generated, the second monostable multivibrator is operated to output a second signal, and the logical product of the first and second signals is taken and the result is output. A method for preventing malfunction in the pulse generation circuit. 6. The method according to claim 5, wherein the logical product is a negative logical product. 7. The pulse generation circuit according to claim 1, wherein said noise is noise generated by static electricity. 8. The method according to claim 5, wherein the noise is noise generated by static electricity.