JPS63105514A - Trigger signal generator by lightening surge - Google Patents

Abstract

PURPOSE:To record the initial time waveform of a lightening surge by comparing an input voltage and a reference voltage by a comparator circuit, inputting an output of the comparator circuit and a signal being the result of retarding the said output to an OR gate where an OR output is obtained and using the output of the OR gate so to active a one-shot multivibrator. CONSTITUTION:A lightening surge voltage inputted from input terminals 1-6 is compared respectively with a reference voltage of a reference voltage generating circuit 10 by comparator circuits 11-16. If a signal having a higher level than the reference voltage is inputted, its output is fed to the OR circuit 30. Then the input signal having a time width equal to or more than the respective delay time of the 1st and 2nd cascade connection circuits 63, 64 is retarded so that its time width is widened by 3 times or over and the result is outputted from an output terminals 74. An output of an OR gate 67 is fed to the one-shot multivibrator 32 where an output signal having a longer prescribed time width is obtained. Since a pulse signal having a wide time width is obtained from a pulse signal having a very short time width in this way, the state of the start of lightening surge production is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a trigger signal generating device for triggering a waveform observation device used for lightning surge waveform observation.

[Prior Art] There is no trigger signal generator for observing lightning surge waveforms that is specifically configured to suit this purpose, and in the past, lightning surge voltage was applied directly to the trigger input terminal of a waveform observation device. Was.

[Problems to be Solved by the Invention] When observing the waveform of a lightning surge, the waveform of the lightning surge is recorded on a waveform recording device with storage capability, such as a storage oscilloscope or a digital memory, and then observed 6. For this purpose, it is necessary to trigger the waveform recording device with a signal at the beginning of the lightning surge occurrence. The signal at the beginning of a lightning surge is pulse-like and has an extremely short duration (approximately 20
nses) signal. Such a short-duration pulse signal from a lightning surge cannot reliably trigger a one-shot multivibrator, for example, but it also cannot record waveforms even when applied directly to the trigger input terminal of a conventional waveform recording device. It is not possible to trigger the device, in which case the waveform recording device is triggered only when a pulse signal of sufficiently long duration is applied. As a result, there was a problem that the initial waveform of a lightning surge was not recorded.

[Means for Solving the Problems] The trigger signal generating device using lightning surge input of the present invention has the following features:
The input voltage and the reference voltage are compared by a comparator circuit, and the output of the comparator circuit is applied to an even number of inverter circuits connected in series to obtain a signal that is in phase with the output and delayed by a predetermined time. Both signals are input to an OR gate to obtain a logical sum, and the one-shot multi-pie break is activated by the output of the OR gate.

[Function] The input pulse that passes through a cascade circuit of an even number of inverter circuits (hereinafter simply referred to as "cascade circuit") is in phase with the input pulse, but is delayed by the passage time of the cascade circuit. For example, if the time width of the input pulse is If it is equal to the transit time,
The time width of the output pulse of the OR gate which receives both the input pulse and the output pulse of the cascade circuit as input is twice the input pulse.

When inputting the output of a cascade circuit to the next cascade circuit, and inputting the input pulse and output pulse of the first cascade circuit and the output pulse of the next cascade circuit to an OR gate, the time width of the output is equal to the input pulse. It will be three times as much. Similarly, the time width of the output pulse is the value obtained by multiplying the time width of the input pulse by the value obtained by adding 1 to the number of column circuits.

[Embodiment] Fig. 1 shows a block diagram of an embodiment of the present invention. In order to simultaneously record lightning surges of six power transmission towers as objects to be observed, six comparison circuits (11) are used.
, (12), (13), (14), (1
5) and (16), and each comparison circuit has input terminals (1), (2), (3), (4), (5),
and (6). A reference voltage is applied to each comparison circuit by a reference voltage generating circuit (1o) so that an output is produced only when a positive or negative signal of a predetermined level or higher is input. The positive and negative voltage values of the reference voltage are set by the setting means (
18) and (19), respectively.

The output of comparison circuits (11) - (16) is 12 human power (12
(having input terminals) is input to the OR circuit (30). The output of the OR circuit (30) is the output of two inverters (61)
and (62) are connected in cascade (hereinafter referred to as the first cascade circuit (63)). The output terminal (72) of the first cascade circuit (63) is similarly input to a circuit (hereinafter referred to as the second cascade circuit (66)) configured by connecting two inverters (64) and (65) in cascade. Ru. 1st
The input terminal (71) and output terminal (7) of the cascade circuit (63)
2) and the output terminal (73) of the second column circuit (66) are connected to the input terminal of the OR gate (67). The output terminal (74) of the OR gate (67) is applied to the input terminal of the one-shot multi-pie break (32).

The output of the one-shot multivibrator (32) is input to an amplifier (33). The amplifier (33) has an input terminal (
The same number of output terminals (41), (42), (
43), (44), (45) and (46), whose output level meets the trigger input standard of the trigger circuit of the waveform recording device (not shown) to which the output terminals (41) to (46) are connected. is set to match. or gate (
The output of 67) is also applied to a monitor circuit (50) constituted by another one-shot multi-pie break, and is made visible on a display (51).

Next, the operation of this embodiment will be explained. Input terminal (1
) to (6), the lightning surge voltage input from one or more input terminals is detected by the comparator circuits (11) to (16).
) is compared with the reference voltage of the reference voltage generation circuit (10). A lightning surge signal is generally a collection of pulse-like signals, and particularly includes pulses with extremely short durations (for example, 10-20 ns) in the initial stage. When a pulse signal with a level higher than the reference voltage is input, the comparison circuit produces an output, which is applied to the OR circuit (30). The output of the OR circuit (3o) is applied to the input terminal (71) of the first column circuit (63). The pulse signal input to the input terminal (71) is phase-inverted by the inverter (61), and then further inverted by the inverter (62), so that the output terminal (72) receives a pulse signal having the same phase as the input pulse signal. and its input pulse signal passes through two inverters (61) and (62) while the time (
T1). Next, the pulse signal at the output terminal (72) is input to the second column circuit (66), and the output terminal (
However, the configuration of the inverters (64) and (65) of the second column circuit (66) is the same as that of the first column circuit (63).
), the phase of the pulse signal at the output terminal (73) is in phase with the phase at the output terminal (72), and the time it takes to pass through the inverters (64) and (65) (T
1) is delayed.

Input terminal (71), output terminal (72) and output terminal (7
The respective pulse signals Sl, S2 and S3 of 3) are input to the or game (67). And its output terminal (7
The waveforms of the signals in step 4) are shown in FIGS. 2a and 2s.

As shown in the figure, the signal (S2) is delayed by time (T1) with respect to the signal (Sl) at the input terminal (71), and furthermore, the signal (S2) is delayed by a time (T1).
3) is delayed by a time (1 block) from No. 18 (S2). signal(
When the pulse width of Sl) is shorter than time (T1) at time (T2), the signals Sl, S2 and S3 are output as independent pulses to the output terminal (74), as shown in Figure 2a.
is output from.

The pulse width of the signal (Sl) is time (T3) and time (T1)
, the signals Sl and S are equal to each other, as shown in FIG.
2 and S3 become continuous signals of time (T4). That is, the input tFs (Sl) at time (T3) is output from the output terminal (7
In 4), the signal is at time 4 with a time width of 31 &. Therefore, 1st and @22 vertical rotation IK (63) and (66)
An input signal having a time width equal to or greater than the time (d1) of each delay time is outputted from the output terminal (74) with a time width three times or more. Second column circuit (66
) and 310th. If the n-th column circuit is connected, the time width of the output signal will be 4M-, , n'+ 1 in the same way as above.
Can be doubled. Note that the time (TI) varies depending on the type of inverter used, and is 10 ns to 2 Or+s when a commercially available product is used.

The output of the AND gate (67) is applied to the one-shot multi-by-break (32) to obtain an output signal having a longer predetermined time width. The output signal is an amplifier (33
) is amplified to the required level by the six output terminals (
41) - (46). In addition, and gate (
67) output is another one-shot multi-by-break (
50), and its output activates a display device (51), such as a light emitting diode, so that the presence or absence of the input signal can be visually checked.

[Effects of the Invention] According to the present invention, a pulse signal with a long time width can be obtained from a pulse signal with an extremely short time width by delaying an input signal using the delay characteristics specific to an inverter. Therefore, the waveform recording device, which cannot be triggered by directly inputting a pulse signal with an extremely short time width at the beginning of a lightning surge, is triggered by a pulse signal with a longer time width to record the situation at the beginning of a lightning surge. be able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS. 2A and 2A are diagrams showing output waveforms. 11-16: Comparison circuit 32: One-shot multivibrator 63.66
: Column circuit 67: OR gate

Claims (1)

[Claims] (1) At least one comparator circuit that generates an output when the input voltage exceeds a preset reference voltage, and at least one even number that receives the output of the comparator circuit as an input and produces an output that is in phase with the input and delayed. a cascade connection circuit of inverters, an OR gate whose inputs are both the input of at least one cascade connection circuit of said inverters and its output, and a trigger signal by a lightning surge input, comprising a one-shot multivibrator operated by the output of the OR gate. Generator.