JPS6336154A - Oscilloscope - Google Patents

Abstract

PURPOSE:To eliminate the need for a high-sped analog sample hold circuit and to specify a section and measure a level with sufficient accuracy by comparing a signal to be measured with a voltage which varies successively and reading the voltage when their coincidence is obtained. CONSTITUTION:The signal to be measured is supplied to a vertical amplifier 2 through the input part 1 of an oscilloscope and displayed on a cathode-ray tube. A sweep voltage from a sweeping circuit 7 is applied to comparators 8 and 9 and compared with the output voltages of D/A converters 10 and 11, and a gate signal generating circuit 12 outputs a gate signal. Digital data C which increases successively up to a specific value is applied from a control circuit 6 to a D/A converter 5, the output of a comparator 4 is supplied as data to D flip-flops 13 and 14, and a gate signal is supplied as a clock signal. Then, when the outputs of the D flip-flops 13 and 14 are inverted, the digital data C is stored and the difference is computed to measure the potential difference between two points of the start and end of a measurement range.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) 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 increased substantially. Etc. How many hours of sampling can be employed.

(Problems to be Solved by the Invention) No matter how many hours of sampling is performed as described above, if the frequency of the signal under test is high, there is a problem that a high-speed analog sample and hold circuit must be used. Ta.

Moreover, this fruiting device had to be expensive.

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;
a second comparison means for comparing the sweep voltage and the second voltage;
generates a pulse with a time width from when the output of the first comparison means is generated to when the output of the second comparison means is generated) f-) i4 pulse generation means and a third voltage that changes sequentially with the signal under test; a third comparing means for comparing, a first detecting means for detecting an inversion of the output of the third comparing means at the leading edge of the time width Noculus outputted from the gate pulse generating means, and a third detecting means for detecting the reversal of the output of the third comparing means at the trailing edge.
second detection means for detecting an inversion of the output of the comparison means;
The apparatus further includes a control side control means for outputting at least a second and a third voltage and storing the third voltage at the time when each detection output by the first and second detection means is generated.

(Function) The sweep voltage from the sweep circuit of the oscilloscope is compared with the first and second voltages by the first and second comparing means, and from the time when the first comparing means generates the output, the second comparing means The time width pulse until the output is generated is output from the i4 pulse generating means.

This time width pulse corresponds to the time width between arbitrary points of the waveform displayed on the oscilloscope, and is also referred to as the measurement range below.

On the other hand, the signal to be measured is compared with a third voltage that increases sequentially by a third comparison means, and is converted into a logic level signal.

The inversion of the output of the third comparison means at the leading edge of the time width pulse output from the gate pulse generation means and the inversion of the output of the third comparison means at the trailing edge are detected by the first and second detection means, respectively. Detected. The third voltage when the detection outputs of the first and second detection means are generated are stored in the control means.

Therefore, when the third voltage changes sequentially while keeping the width of the time width constant, the outputs of the first and second detection means will be such that the third voltage is equal to the voltage to be measured. Since the third voltage at this time is stored in the control means, the voltage to be measured at the beginning of the measurement range and the voltage to be measured at the end of the measurement range are respectively be measured. Furthermore, the potential difference can also be measured by calculating the difference between both voltages.

Here, the signal under test is converted into a signal at a logic level by the third comparison means, and the signal under test converted into the signal at the logic level is digitally sampled in the first and second detection means. will be done. Further, the sampling pulse for this sampling is equivalently outputted from the date pulse generating means.

Furthermore, it is easy to change the measurement range by changing the first voltage and the second voltage, and by outputting the first and second voltages as digital data from the control means, it is possible to convert the first and second voltages into analog voltages. The accuracy of the measurement range is determined by the resolution of the D/A conversion means for this purpose, and there is no need for a complicated circuit for improving resolution.

(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 tube. Further, the output from the input section 1 is branched to an amplifier 3, amplified, and applied to a comparator 4 as a voltage to be compared. Is the analog voltage output from the D/A converter 5 ? It is applied to the regulator 4 as a comparison voltage.

The sweep voltage output from the sweep circuit 7 of the oscilloscope is applied to comparators 8 and 9 as voltages to be compared. Analog' output from D/A converter 10.11
The sleep pressure is applied to comparators 8 and 9 separately as comparison voltages. The outputs of comparators 8 and 9 are r-
) is supplied to the signal generation circuit 12 and generates a dirt signal during a period in which the output from the sweep circuit 7 is greater than or equal to the output analog voltage of the D/A converter 10 applied to the comparator 8 and less than the output analog voltage of the converter 11. A dirt signal is output from the circuit 12.

On the other hand, digital data A is sent from the control circuit 6.

B is separately applied to the A converters 10 and 11, respectively, and converted into analog voltages by D/A converters 10 and 11. Further, from the control circuit 6, the digital data C which is sequentially increased up to a predetermined value by counting /4' pulses, which are driven in synchronization with the control circuit 6, is applied to the D/A converter 5. is converted to an analog voltage at

The outputs of the controller i and the regulator 4 are supplied to the D7 lipfrogs 13 and 14 as data. Further, the output from the dirt signal generation circuit 12 is supplied to the D flip-flop 70 f14 as a clock signal, and the output from the dirt signal generation circuit 12 inverted by the inverter 16 is supplied to the D flip-flop 13 as a clock signal.

If the output of the comparator 4 is inverted by comparing the two forces in the comparator 4, that state is supplied to the D flip-flops 7'13 and 14. D flip 70tsu 7'
Reference numeral 14 receives the output of the comparator 4 at the rising edge of the output of the dirt signal generating circuit 12, that is, at the beginning of the measurement range. The D free lag flop 13 is connected to the y-to signal generation circuit 12.
The output of the comparator 4 is input at the falling edge of the output, that is, at the end position of the measurement range. The outputs of the D flip-flops 13 and 14 are read into the control circuit 6. The digital data C when the D flip-flops 13 and 14 read the inversion of the output of the comparator 4 is stored in the control circuit 6.

In one embodiment of the present invention configured as described above, the sweep voltage waveform from the sweep circuit 7 is as shown in FIG. 2(a). Dizotal data A output from the control circuit 6
If the analog signals converted separately by the D/A converters 10 and 11 for Bi and Bi are "E" u F #,
Analog signal “E”.

F'' and the sweep voltage are compared in converter/motherboards 8 and 9, and the dirt signal generation circuit 12 outputs the date signal shown in FIG. 2(b).This r-to signal will be described later. Indicates the measurement range.This dart signal is digital data A,
By setting B, the position and width within the sweep section can be changed.

Also, normally, as shown by the two-dot chain line in FIG. A voltage from a constant voltage source having the sweep start voltage E1 may be applied to.

Now, assume that the signal waveform to be measured is as shown in FIG. 3 (@), and FIG. 2(b) is rewritten in FIG. 3(-).

Further, an analog signal G from the D/A converter 5 based on the digital data C, that is, a comparison voltage is shown by a broken line in FIG. 3(e). It should be noted that the right side and left side of FIG. 3 are shown with different comparison voltage levels.

The output of the comparator 4 is as shown in FIG. 3(d) based on the signal under test shown in FIG. 3(e) and the comparison voltage output from the D/A converter 5. This output of the comparator 4 is taken in by the D fritz flop circuits 13 and 14. That is, the output of the comparator 4 is taken in by the D flip-flop 14 at the beginning (rising edge) of the predetermined range, and the output of the D flip-flop 14 is as shown in FIG. 3(c). Flip Flora: 7°13
As a result, the output of the converter 4 is taken in at the end of the measurement range (falling edge 9), and the output of the D flip-flop 13 becomes as shown in FIG.

Therefore, the digital data B is used for setting the start of measurement, and the digital data B is used for terminating the measurement, and is incremented. During one increment of this increment, the digital data C is changed over the entire measurement range of the signal level under test. By storing the digital data Ci at the time of inversion of the output of the D flip-flop 13 during this change, it is possible to convert the signal under test and the measurement period into digital data. In this case, D flip-flop 13 (14)
Storing the deisotal data C at the time of output inversion of the D flip-flop 13 (14) acts as a digital sample and hold circuit, and its sampling period is determined by the comparator 8°9 and the D/A converters 10 and 11. ,
If the digital data A and B are fixed in the dirt signal generation circuit 12 and the sweep signal has good linearity, it can generate short-period sampling pulses and functions as a substantial sampling pulse generation circuit. Note that the sampling pulse period is the level VA of the swept sawtooth wave.
Since it corresponds to the value obtained by converting the level divided by the resolution of conversion 10.11 into time, a constant short-period sampling pulse can be obtained.

Furthermore, if the width of the dirt signal generated by the dirt signal generation circuit 12 is determined, the comparison voltage of the three converters 5,
In other words, by changing the digital data C,
ft111 Voltages H, J and I at the beginning and end of the fixed range,
K can be measured from the dizotal data C when the control circuit 6 reads the change in the output of the D flip-flop 14.13, and the difference between voltages H and I, 'voltages J and K.
By calculating the difference between
Potential difference between points can be measured.

In this case, the designation of the C1 measurement range, that is, the predetermined section, can be designated by digital data A and B, and can be set according to the resolution of the converters 10 and 11. Furthermore, in this case, the time difference between the start point and end point of the measurement range can be obtained from the difference between the daily data B and A.

(Effects of the Invention) According to the present invention, since a time width pulse is generated by comparing the sweep voltage with the first and second voltages, it is easy to specify between arbitrary points.

Furthermore, if the second and third voltages are output as deisotal signals from the control means, each time the first voltage is set as the measurement starting low voltage and is changed to the second voltage, the third voltage is changed to generate the signal under measurement. By reading the level and the third voltage when a single attack is detected, it becomes possible to take in the signal under measurement as dezotalized data. It is also possible to make a hard copy of the imported data.

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

Furthermore, in the above case, a converter is required to convert the second to third voltages given by the distal signals to the second to third comparators and apply the analog signals.
The practical minimum width of the sampling signal υ is determined by the resolution of the /A converter, and a complicated circuit for improving resolution is not required.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIGS. 2 and 3 are waveform and timing diagrams for explaining the operation of an embodiment of the present invention. 4.8 and 9...comparators, 5.10 and 1
1...D/A converter, 6...ll1iθ control circuit, 7
...Sweep circuit, 13 and 14...D flip-flop.

Claims (1)

[Claims] a first comparison means for comparing the sweep voltage and the first voltage;
a second comparison means for comparing the sweep voltage and the second voltage;
gate pulse generating means that generates a time width pulse from the time when the output of the first comparing means is generated to the time when the output of the second comparing means is generated; a first detection means for detecting an inversion of the output of the third comparison means at the leading edge of the time width pulse outputted from the gate pulse generation means; and an inversion of the output of the third comparison means at the trailing edge. a second detection means that outputs at least a second and a third voltage, and a second detection means that outputs at least a second and a third voltage;
An oscilloscope comprising: a control means for storing a third voltage at the time of inversion of each detection output by the detection means.