JPS63118669A - Oscilloscope - Google Patents

Abstract

PURPOSE:To facilitate setting and changing a measurement range by comparing a sweep voltage and a first voltage with each other to output a pulse having the time width corresponding to the period which begins at the start of sweep and ends at the time when the sweep voltage exceeds the first voltage. CONSTITUTION:The sweep voltage from a sweeping circuit 7 is compared with the first voltage by a first comparator 4, and the pulse having the time width corresponding to the period from the start of sweep to the output generation of the comparator 4 is outputted from a gate signal generator 10. Meanwhile, a signal to be measured is compared with a second voltage by a second comparator 8 and is changed to a logical level signal. With respect to the pulse outputted from the generator, inversion of the output of the comparator 8 is detected and the second voltage is stored in a control circuit 6. Consequently, if the width of said pulse is fixed and the second voltage is changed in this state, the output of a detecting means is inverted when the second voltage is equal to the voltage to be measured, and it is stored in the circuit 6 to measure the voltage to be measured. The signal to be measured is converted to the logical level signal by the comparator 8, and a sampling pulse is equivalently outputted from the circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an oscilloscope that can be used as a digital storage oscilloscope, etc., and that facilitates digitization of the signal level to be measured.

(Prior Art) In some cases, a signal under test is sampled, stored as digital data, and the stored digital data is processed.

In such a case, if the frequency of the signal under test is high, the sampling frequency for sampling the signal under test must be increased, and if the signal under test has a repetitive waveform, the sampling frequency must be substantially lowered. Equivalent time sampling is employed.

(Problems to be Solved by the Invention) Even with the random sampling as described above, there is a problem that a high-speed analog sample and hold circuit must be used when the frequency of the signal under measurement is high.

Moreover, this fruiting device had no choice but to become a masterpiece.

The present invention has been made in view of the above, and provides an oscilloscope that solves the above problems, eliminates the need for a high-speed analog sample-and-hold circuit, and makes it possible to specify intervals and measure levels with sufficient accuracy. The purpose is to

(Means for Solving the Problems) In order to solve the above problems, the present invention is configured as follows.

a first comparison means for comparing the sweep voltage and the first voltage;
gate pulse generating means for generating a pulse with a time width from the start of the sweep to the time when the output of the first comparing means is generated; and a second comparing means for comparing the signal under measurement with a second voltage that is sequentially changed. , detection means for detecting an inversion of the output of the second comparison means at the trailing edge of the time width pulse output from the gate pulse generation means; As well as changing the
and a control means for storing a second voltage when the detection output is generated by the detection means.The sweep voltage from the sweep circuit of the oscilloscope is compared with the first voltage by the first comparison means. , a time width pulse from the start of the sweep to the time when the output of the first comparison means is generated is outputted from the gate pulse generation means.

On the other hand, the signal to be measured is compared with a second voltage that is successively changed by a second comparison means, and is changed into a signal at a logic level.

The detection means detects an inversion of the output of the second comparison means at the trailing edge of the time width pulse output from the gate pulse generation means, and the second voltage at the time when the detection output of the detection means is generated is stored in the control means. Ru.

Therefore, when the second voltage is sequentially changed while keeping the width of the time pulse constant, the output of the detection means is reversed just in case the second voltage becomes equal to the voltage to be measured. Since the second voltage of is stored in the control means,
The measured voltage at the trailing edge of the time width pulse will be measured.

Here, the signal under test is converted into a signal at a logic level by the second comparison means, and the signal under test converted into the signal at the logic level is digitally sampled by the detection means. Further, the sampling pulses of this sampling are output isometrically from the gate pulse generating means.

Furthermore, it is easy to change the width of the time width pulse by changing the first voltage, and the control means can easily change the width of the time width pulse by changing the first voltage.
If the voltage is output as digital data, the accuracy of the time width pulse is determined by the resolution of the D/A conversion means for converting it into an analog voltage, and a complicated circuit for improving the resolution is not required.

(Example of the invention) The present invention will be explained below using examples.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

A signal to be measured is supplied to a vertical amplifier 2 via an input section 1 of the oscilloscope, and is amplified and displayed on a cathode ray tube. Further, the output of the input section 1 is branched to an amplifier 3, amplified, and applied to a comparator 4 as a voltage to be compared. D
The analog voltage output from the /A converter 5 is applied to the comparator 4 as a comparison voltage.

A sweep voltage output from the sweep circuit 7 in response to the trigger signal is applied to the comparator 8 as a voltage to be compared. D/
The analog voltage output from the A converter 9 is applied to the comparator 8 as a comparison voltage. The trigger signal and the output from the comparator 8 are supplied to the gate pulse generation circuit 10, and the gate signal is outputted from the gate pulse generation circuit 10 during the period from when the trigger signal is generated until the sweep voltage exceeds the comparison voltage of the comparator 8. .

On the other hand, digital data A is applied from the control circuit 6 to the D/A converter 9 and converted into an analog voltage. Further, from the control circuit 6, digital data B, which is sequentially increased to a predetermined value by counting pulses driven synchronously by the control circuit 6, is applied to the D/A converter 5 and converted into an analog voltage.

The output of the comparator 4 is supplied to a D flip-flop 13 as data. Further, the output from the gate pulse generation circuit 10 inverted by the inverter 16 is supplied to the D flip-flop 13 as a clock signal.

The output of the comparator 4 is taken in by the D flip-flop 13 at the falling edge of the output of the gate pulse generation circuit 10.

When the output of the D flip-flop 13 is inverted by reading the output of the comparator 4, it is detected by the control circuit 6, and the digital data B at the time of this detection is stored in the control circuit 6.

In one embodiment of the present invention constructed as described above, the signal waveform to be measured is as shown, for example, by the solid line l in FIG. 2(f), and the trigger level is set to Assume that it is as shown. As a result, the trigger signal is as shown in Figure 2 (
The output signal from the sweep circuit 7 becomes as shown by the solid line k in FIG. 2(a), and the output signal from the sweep circuit 7 becomes as shown by the solid line l in FIG. 2(a). It also receives digital data B output from the control circuit 6 and receives D/
The analog signal m output from the A converter 5, that is, the comparison voltage is shown by the broken line m in FIG.
The left side and right side of the figure are shown with different comparison voltage levels.

The output n of the comparator 4 becomes as shown in FIG. 2(e) due to the measured signal i shown in FIG. 2(f) and the comparison voltage m output from the D/A converter 5. Comparator 4
This output n is taken into the D flip-flop 13.

On the other hand, in response to the digital data A output from the control circuit 6, the analog signal O output from the D/A converter 9
is indicated by the dashed-dotted line O in FIG. 2(a), and in accordance with the output from the comparator 8, the output p of the gate pulse generation circuit 10 becomes as shown in FIG. 2(C), and the gate pulse generation circuit The output q of the gate signal generation circuit 10 obtained by inverting the output p of the gate signal generation circuit 10 using the inverter 16 is shown in FIG. 2(d).
It will look like this. The output n of the comparator 4 is taken in by the D flip-flop 13 at the rising edge of the output q of the inverter 16, that is, the falling edge of the output p of the gate signal generation circuit 10, and the output from the D flip flop 70 knob 13 is as shown in FIG. 2(g). as shown by the solid line S.

Here, digital data A is used for setting the width of the time width pulse. Therefore, the digital data B is set to a predetermined value, the @ of the time width pulse is set, and while this setting range is maintained, the digital data B is varied over the entire range of the signal level to be measured. During this change, when the output of the D flip-flop 13 is inverted, digital data B is stored. As a precaution, the signal under test can be converted into digital data over the measurement period.

In this case, the D flip-flop 13 and storing the digital data B at the time of inverting the output of the D flip-flop 13 act as a digital sample and hold circuit, and the sampling period is determined by the comparator 8, the D/A
If the linearity of the sweep signal is determined by the converter 9, the gate pulse generation circuit 10, and the digital data person, and the linearity of the sweep signal is good, a sampling pulse with a substantially short pulse width will be obtained immediately after the trigger starts, and as the digital data A increases. Therefore, the pulse width of the sampling signal becomes longer.

Furthermore, the width of the gate pulse generated by the gate pulse generation circuit 10 can be changed by changing the digital data A, and the measurement range can be changed by this change.

(Effects of the Invention) As explained above, according to the present invention, the sweep voltage and the first voltage are compared, and a time width pulse is output for the period from the start of the sweep until the sweep voltage exceeds the first voltage. This makes it easy to set and change the measurement range.

Also, comparing the second voltage and the voltage to be measured using a comparison means,
It is designed to detect that the output of the comparison means is inverted at the trailing edge of the time width pulse, and to store the second voltage at the time of this detection. The signal can be digitized and captured as data.

It is also possible to make a hard copy of the data imported by Mayu.

Furthermore, since sample and hold can be performed digitally, a high-speed analog sample and hold circuit is not required.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a timing chart for explaining the operation of one embodiment of the present invention. 4 Work 8... Comparator, 5 and 9- D/A
Converter, 6 control circuit, 7... sweep circuit, 10... gate signal generation circuit, 13... flip 70 tubes.

Claims (1)

[Claims] a first comparison means for comparing the sweep voltage and the first voltage;
gate pulse generation means for generating a pulse with a time width from the start of the sweep to the time when the output of the first comparison means is generated;
a second comparison means for comparing the signal under test with a second voltage that is sequentially changed; and a second comparison means for inverting the output of the second comparison means at the trailing edge of the time width pulse output from the gate pulse generation means. a detection means for detecting, outputting at least the first and second voltages, changing the second voltage, and storing the second voltage when the detection output by the detection means is inverted; An oscilloscope characterized by comprising a control means.