JPH02307066A - Digital oscilloscope - Google Patents

Abstract

PURPOSE:To set the mutual phases of waveform data of different channels optionally and to process and display them by giving an address, which is selected by a read address control circuit and output to the memory of a selected channel, an optional address offset according to phase setting data. CONSTITUTION:Analog signals of channels CH1 and CH2 are A/D-converted 1 and written as waveform data on memories 2. The waveform data are read out to an arithmetic circuit 4 and a display control circuit 5 according to addresses applied from a readout address control circuit 5. Further, the selected addresses are given an optional address offset by an adder subtracter 6 according to phase setting data. The circuit 4 processes the waveform data of the channel CH2 read out with the address given the offset and the waveform data of the channel CH1 read out with the original address and those resulting data are displayed 7 through the circuit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a digital oscilloscope, and more particularly, to an improvement in the mutual calculation and display function of waveform data of different channels.

<Prior art> A type of digital oscilloscope converts analog input signals from multiple channels into waveform data using an A/D converter provided for each channel, and writes the converted data into a memory provided for each channel. Some devices are configured to perform various digital arithmetic processing on waveform data read from a memory and then display it on a display such as a CRT.

In such a digital oscilloscope, a power waveform is also displayed by multiplying, for example, the @flow liquid type displayed on one channel by the voltage waveform displayed on the other channel.

<Problems to be Solved by the Invention> However, depending on the object to be measured, the current and voltage may not be measured at the position where the power waveform is desired to be measured, and the current and voltage may have to be measured at different positions.

As a result, the correct power waveform will not be displayed because the phase relationship between the measured signals is different from the actual phase relationship at the desired observation point.

The effect of such a phase shift becomes more pronounced as the frequency of the measurement signal increases, and is known to be noticeable when measuring the power waveform of a switching power supply that switches at high frequencies.

The present invention has focused on these points, and its purpose is to provide a digital oscilloscope that can arbitrarily set the mutual phases of waveform data of different channels and display the calculated results.

Means for Solving the Problems> The digital oscilloscope of the present invention converts analog input signals of multiple channels into waveform data using an A/D converter provided for each channel, and converts the analog input signals of multiple channels into waveform data using a memory provided for each channel. A read address control circuit outputs an address for simultaneously reading waveform data from each memory in a digital oscilloscope that writes waveform data stored in each memory, reads the waveform data stored in each memory, performs digital arithmetic processing, and displays the data on the display section. Then, an adder/subtractor is provided to give an arbitrary address offset 1- to the address output from the read address control circuit to the memory of the selected channel based on the phase setting data, and the address to which these offsets are added is used to The present invention is characterized in that the waveform data of the channel to be read and the waveform data of the channel to be read are calculated and displayed based on the waveform data of the channel to be read and the address to which no offset is given.

Effect> The phase between displayed waveforms can be set arbitrarily by giving an arbitrary address offset based on the phase setting data.
Calculated waveforms in various phase relationships can be displayed.

Example Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.
In Figure 0, which shows an example of channel input, the analog input signals of each channel CH1 and CH2 are converted into digital signals by the A/D converter 1 provided for each channel, and are provided as waveform data for each channel. is written to memory 2. These waveform data written in the memory 2 are simultaneously read out to the arithmetic circuit 4 and the display control port FRI5 according to the address applied from the read address control circuit 3. Note that an arbitrary address offset is given by the adder/subtractor 6 to the address output from the read address control circuit 3 to the memory of the selected channel (channel 2 in this embodiment) based on the phase setting data. The arithmetic circuit 4 calculates (for example, multiplies) the waveform data of channel CH2 read by the address to which these offsets are given and the waveform data of channel CH1 read by the address to which no offset is given, and outputs the result to the display control circuit 5. The display control circuit 5 controls each of these channels CHI, CH
The waveform data read from the memory 2 and the a1N result calculated by the calculation circuit 4 are simultaneously or selectively CR
It is displayed on a display 7 such as T.

With this configuration, by changing the phase data input to the adder/subtractor 6, channel CH2
The displayed waveform can be moved along the time axis of the display 7, and if the phase difference between the two waveforms is known, the phase is corrected to match that phase difference on the display screen and the calculated waveform of both waveforms is calculated. can be displayed.

It is also possible to simulate on the display screen how the power waveform changes when the phase changes based on the measured waveform.

FIG. 2 is an explanatory diagram of the operation of FIG. 1. (a) shows each channel C when the phase data input to the adder 6 is O.
Display waveforms A and B of HI and CH2 are shown. (b) inputs the phase data that gives the phase of τ to the adder 6,
(C) shows a display waveform B- obtained by advancing the phase of the display waveform B of channel CH2 shown in (a) by τ.
is the multiplication waveform C (C=
AXB-) is shown.

In the above embodiment, an example of two-channel input is shown, but in the case of three or more channels of input, a plurality of display waveforms may be selectively combined and calculated and displayed.

Further, the calculation is not limited to multiplication, and various calculation functions can be provided.

<Effects of the Invention> As explained above, according to the present invention, it is possible to realize a digital oscilloscope that can arbitrarily set and display the mutual phase of waveform data of different channels, and can calculate the phase difference of voltage and current and the phase difference of power waveform. Suitable for analyzing relationships, etc.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the operation of FIG. 1.

Claims (1)

[Claims] Analog input signals of a plurality of channels are converted into waveform data by an A/D converter provided for each channel, and the data is written in a memory provided for each channel, and the data is stored in each memory. In a digital oscilloscope that reads out waveform data, performs digital arithmetic processing, and then displays the data on the display, there is a read address control circuit that outputs an address for simultaneously reading waveform data from each of the memories; An adder/subtractor is provided that gives an arbitrary address offset to the address output to the memory of the channel that has been set, based on the phase setting data, and the waveform data of the channel that is read by the address to which these offsets have been given and the address to which no offset has been given is A digital oscilloscope that calculates and displays the waveform data of the read channel.