JPH01113673A - Generating circuit of time difference pulse for oscilloscope - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 〔overview〕 Regarding time difference pulse generation circuit for oscilloscope.

The purpose is to make it possible to measure waveforms at any time with a low-cost oscilloscope.

Input the standard pulse generation circuit whose frequency can be set and the output of the standard pulse generation circuit as the clock.

It consists of a binary counter whose count number can be set using the input wave as a gate power, and an AND circuit which takes the logical product of the output of the standard pulse generation circuit and the output of the binary counter.
The output of the AND circuit is configured to be usable as a trigger signal for an oscilloscope.

[Industrial application field]

The present invention relates to a time difference pulse generation circuit for an oscilloscope.

Traditionally, large period square waves (e.g. ioo.

In order to see changes in the time period of several milliseconds (more than ms), it is not possible to clearly see changes in the waveform just by triggering the input wave, and it is necessary to use a storage oscilloscope etc. to search for it. There wasn't. however,
Since storage oscilloscopes are expensive, it has been necessary to develop a means for observing changes in a time zone of several cubic meters within a square wave with a large period using an inexpensive general oscilloscope.

[Conventional technology]

Conventionally, it has been necessary to use an inexpensive general oscilloscope to observe changes in a time period of about several milliseconds in a square wave with a large period (for example, about 10,100 ohms or more).

The rising or falling edge of an input wave was used as a trigger to be input to an oscilloscope and displayed on the oscilloscope's CRT.

For example, input an IHz input wave to the device under test.

When measuring the output waveform, the difference between the falling edge of the input wave and the falling edge of the output wave must be less than msL.

When displaying on an oscilloscope using the falling edge of the input wave as a trigger, on a general-purpose oscilloscope.

Since the start of the horizontal sweep is delayed compared to the vertical amplification output, changes in the first few milliseconds of the fall of the output wave are only slightly displayed toward the left end of the CRT.

It was difficult to reliably observe the changed parts.

Another possibility is to use the trigger built into the oscilloscope, but in this case, the timing to press the trigger button cannot be determined accurately, so it is best to display the changing part of the waveform you want to observe in the center of the CRT. It was difficult and took time and effort to measure.

[Problem that the invention seeks to solve]

Conventionally, when measuring a part of a long-period waveform with a low-cost general-purpose oscilloscope, it has been difficult to measure a part of a long-period waveform (related to the input wave).

A problem has arisen in that it is difficult to display only the waveform portion within a narrow time period specified by the measurer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a time difference pulse generation circuit for an oscilloscope, which allows waveforms in any time zone to be measured using a low-cost oscilloscope.

[Means for solving problems]

The present invention includes a standard pulse generation circuit that can set one frequency, a binary counter that inputs the output of the standard pulse generation circuit as a clock and uses the input wave as a gate input and can set the number of counts, and the output of the standard pulse generation circuit and the binary counter. It consists of an AND circuit that takes logical product with the output of the counter, and
By configuring the output of the D circuit to be usable as a trigger signal for an oscilloscope, it is possible to measure waveforms in any time period with a low-cost oscilloscope.

FIG. 1 is a diagram explaining the principle of the present invention.

In FIG. 1, 1 is a time difference pulse generation circuit, 2 is a standard pulse generation circuit, and 3 is a binary counter.

4 is an AND circuit.

The time difference pulse generation circuit 1 includes a standard pulse generation circuit 2, a binary counter 3, and an AND circuit 4.

The standard pulse generation circuit 2 can be set to any frequency and generates a clock.

The binary counter 3 can set an arbitrary count number, and has a gate input terminal (Gat
While e In ) is ON, the clock output from the standard pulse generation circuit 2 is counted, and when the set count is reached, the output terminal (out) is turned ON.

The AND circuit 4 takes the AND sum of the output clock of the standard pulse generation circuit 2 and the output of the binary counter 3, and
Use as a trigger signal for an oscilloscope. The function of the AND circuit 4 is to synchronize the output of the binary counter 3 with the output clock of the standard pulse generation circuit 2, thereby removing whisker-like noise in the output waveform of the binary counter 3.

[Effect]

First, determine how many seconds after the rise of the input wave to observe.
This is done manually by setting the frequency of the standard pulse generation circuit 2 and the count number of the binary counter 3. Then, the output clock of the standard pulse generation circuit 2 and the output of the binary counter 3 are input to the AND circuit 4, and as a result, a trigger is generated a predetermined number of seconds later than the input wave, and this trigger is used as the trigger of the oscilloscope. By inputting the information, the waveform of any time period that the measurer wishes to observe is displayed on the CRT of the oscilloscope.

(Example〕 FIG. 2 is a configuration diagram of one embodiment of the present invention.

In FIG. 2, 21 is a time difference pulse generation circuit.

22 is a standard 5 standard pulse generation IC, 23 is a binary counter, 24 is an AND circuit, and 25 is a device to be measured.

26 is an oscilloscope.

The time difference pulse generation circuit 21 includes a standard pulse generation IC 22.
, a binary counter 23 and an AND circuit 24.

The standard pulse generation IC 22 can be set to any frequency and generates a clock.

The binary counter 23 can be set to any number of counts, and can be used with a standard pulse generation IC.
Count the input waves using the clock output by 22,
Output the result.

The AND circuit 24 sums the output clock of the standard pulse generation IC 22 and the output of the binary counter 23, and outputs a trigger for the oscilloscope. At this time, since the output waveform of the binary counter 23 has a whisker, it is possible to output a trigger for the oscilloscope in synchronization with the output clock of the standard pulse generation IC 22.

The device under test 25 is a device for measuring the output waveform of a printed circuit board or the like with an oscilloscope.

The input wave, the output wave, and the trigger that is the output of the time difference pulse generation circuit 21 are input to the oscilloscope 26, and the CR
The output waveform of the device under test is displayed on T.

The operation example shown in FIG. 2 will be explained below.

Assume that the frequency of the input wave is IHz (period: 100100O), and the difference between the rise of the input wave and the rise of the output wave of the device under test is several ms.

Therefore, the frequency of the standard pulse generation IC in the 1-time difference pulse generation circuit 21 is set to 33Hz, and the binary counter 2
Set the count number of 3 to 15.

Then, a trigger is output from the AND circuit 24 495 ms later than the falling edge of the input wave.

Since this trigger is input to the oscilloscope.

The waveform is displayed in the center of the oscilloscope's CRT.

FIG. 3 is a diagram showing each waveform of an input wave, an output wave, and a trigger.

From Figure 3, the trigger is 495 from the falling edge of the input wave.
It is output when there is a delay of ms, and the number m3 to be measured is included in the trigger period.

It can be seen that the waveform to be measured is displayed in the center of the CRT of the oscilloscope.

〔Effect of the invention〕

According to the present invention, it is possible to measure waveforms in any time period with a low-cost oscilloscope without using an expensive device such as a storage oscilloscope.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle of the present invention, FIG. 2 is a configuration diagram of one embodiment of the present invention, and FIG. 3 is a diagram of each waveform. In Figure 1, 1: Time difference pulse generation circuit 2 - Standard pulse generation circuit 3: Binary counter 4: AND circuit

Claims (1)

[Claims] A standard pulse generation circuit (2) whose frequency can be set, and a binary counter (3) whose count number can be set, which inputs the output of the standard pulse generation circuit (2) as a clock and uses the input wave as a gate input. ), the output of the standard pulse generator (2) and the binary counter (
3. A time difference pulse generation circuit for an oscilloscope, comprising an AND circuit (4) that performs a logical product with the output of step 3), and the output of the AND circuit (4) can be used as a trigger signal for the oscilloscope.