JPH032673A - Reference waveform display device for real time 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 [Field of Industrial Application] The present invention relates to a display device for a reference waveform in a real-time oscilloscope. More specifically, it is an object of the present invention to provide a device that enables observation of a measured waveform in a real-time oscilloscope by comparing it with a reference waveform.

[Prior Art] It is often desired to compare a waveform observed with an oscilloscope with a reference waveform. For example, a reference waveform may be used as a pass/fail criterion for a signal to be measured in a manufacturing line or a receiving inspection department. The fourth section describes how to judge whether the signal under test is pass/fail using such a reference waveform.
This will be explained using figures.

FIG. 4 shows the tube surface of the oscilloscope, where 120 is the signal to be measured, 121 is the upper limit reference signal, and 12
2 is a lower limit signal. The signal under test 120 is the upper limit signal 12
1 and the lower limit signal 122, the signal under test is determined to be acceptable.

In a digital oscilloscope that A/D converts the signal under test, stores it, and then displays it, the upper limit reference signal 121 and lower limit reference signal 122 are displayed on the tube surface of the oscilloscope at the same time as the signal under test. however,
In a real-time oscilloscope, the waveform of such a reference signal is drawn on transparent paper, which is then attached to the oscilloscope tube to observe the signal under test.

The fifth example of the circuit configuration of a conventional real-time oscilloscope is
Reference numerals 11 and 12 shown in the figure and whose operation will be explained are input terminals for applying two signals to be measured, and the applied signals to be measured are amplified by the vertical axis preamplifier 13, The signal is further amplified and applied to the vertical axis deflection plate of the cathode ray tube 15.

A part of the output of the vertical axis preamplifier 13 is applied to a trigger generation circuit 16 to obtain a trigger signal synchronized with the signal under test, which is applied to a sawtooth wave generation circuit 17 to start a sawtooth wave. The sawtooth wave synchronized with the signal under measurement, which is the output of the sawtooth wave generation circuit 17, is amplified by the horizontal axis amplifier 18 and applied to the horizontal axis deflection plate of the cathode ray tube 15. The sawtooth wave generation circuit 17 outputs an unblanking signal so that the cathode ray tube 15 draws a waveform during the positive slope time of the sawtooth wave, for example.
This is applied to the Z-axis amplifier 19, amplified, and applied to the grid of the cathode ray tube 15.

The vertical axis and horizontal axis setting conditions are vertical axis preamplifier 1.
3 and from the sawtooth wave generation circuit 17 to the symbol generation circuit 2
0 and is stored in the symbol set memory 21, and the Y and X coordinates of the extracted symbols are plotted on the vertical axis D/
The D/A converter 22 and the horizontal axis D/A converter 23 perform D/A conversion and apply it to the cathode ray tube 15 via the vertical axis main amplifier 14 and the horizontal axis amplifier 18, respectively. , unblanking signals are outputted from the symbol generating circuit 20 and applied to the cathode ray tube through one Z-axis amplifier, and various setting conditions of the vertical and horizontal axes are displayed in letters or the like simultaneously with the waveform display.

[Problems to be Solved by the Invention] In a digital oscilloscope that A/D converts the signal under test, stores it, and then displays it, upper and lower limit reference signals are displayed on the oscilloscope screen to determine whether the signal under test is pass/fail. could be facilitated.

However, in real-time oscilloscopes, it has not been possible to display such a reference signal on the screen at the same time as the signal under measurement. For this reason, it is extremely inconvenient and inefficient to observe the signal under measurement using a real-time oscilloscope on a production line or the like and judge whether the signal is acceptable or not.

[Means to solve the problem] In conventional real-time oscilloscopes, characters,
Symbols such as codes were displayed on the oscilloscope tube at the same time as the measured signal, but in order to display the reference signal on the tube in the same way as these symbols, various waveform pieces were used to make up the reference signal. A waveform set memory means for storing the waveform set memory means and a reference waveform generating means for generating a reference waveform by reading out and combining various waveform pieces stored in the waveform set memory means are provided.

[Operation] Many types of waveform pieces are stored in advance in the waveform set memory means, and the reference waveform generation means selectively and sequentially reads out the various stored waveform pieces and assembles a reference waveform to be a reference signal. This is displayed on the screen at the same time as the signal being measured.

[Example] An example of the circuit configuration of a real-time oscilloscope implementing the present invention is shown in FIG. 1, and will be explained using this. Here, components corresponding to those shown in FIG. 5 are given the same numbers.

The configuration in Figure 1 is similar to the conventional real-time system shown in Figure 5.
The configuration of the oscilloscope is used as is, and a reference waveform generation circuit 50 and a waveform set memory 51 are added thereto. Therefore, since the operations other than this addition are the same as those already explained in FIG. 5, the addition will be explained here.

The waveform set memory 51 stores many types of waveform pieces for configuring a reference waveform.

A specific example of the circuit configuration of the reference waveform generation circuit 50 is shown in FIG. When the waveform select switch 71 is operated here, the waveform select counter 61 is operated, and a desired waveform piece can be selected from the various waveform pieces stored in the waveform set memory 51. When the address switch 72 is operated, the address counter 62 operates to determine at which address (position on the X axis) on the screen the selected waveform piece is to be positioned, and the selected waveform piece is Instructs the address to be stored in the reference waveform memory 64 for storage at a desired location. Position switch 73
When you operate the position counter 63,
The position of the selected waveform piece on the tube surface (position on the Y axis) is determined, and this is specified to the reference waveform memory 64.

The waveform piece selected in this way is at the specified address (position on the X-axis) and position (position on the Y-axis).
The reference waveform is stored in the reference waveform memory 64, and this operation is repeated to complete the reference waveform. Reference waveform memory 64
outputs this reference waveform to the vertical axis D/A converter 22 according to instructions from the symbol generation circuit 20, and the reference waveform is displayed on the screen in the same manner as the symbols are displayed.

The configuration of this reference waveform will be explained in detail using FIG. 3.

FIG. 3(a) illustrates waveform pieces 101 to 107 stored in the waveform set memory 51. Same figure (b)
, a reference waveform constructed using these waveform pieces 101 to 107 is shown.

First, operate the waveform select switch 71 to
The waveform piece 101 is selected from the waveform pieces 101 to 107 shown in a). Next, address switch 72 is operated to set address O. Then, position switch 73 is operated to set position 3. Then, the waveform piece 101 at the left end in FIG. 3(b) is obtained. Similarly, waveform piece 101 is selected and address 1. When position 3 is set, the second waveform piece 101 from the left in FIG. 3(b) is obtained. Roughly select the waveform piece 102 and enter address 2. When position 3 is set, the waveform piece 102 shown in FIG. 3(b) is obtained. Also, select the waveform piece 103 and address 2. When position 4 is set, the leftmost waveform piece 103 in FIG. 3(b) is obtained. By repeating similar operations, a reference waveform consisting of many waveform pieces as shown in FIG. 3(b) is constructed, and this is stored in the reference waveform memory 6.
It is stored in 4.

If two sets of reference waveform memories 64 are provided here, the upper limit and lower limit reference signals 121 and 122 as shown in FIG.
can be configured and stored.

In FIG. 1, the reference waveform generation circuit 50 and the waveform set memory 51 are shown as separate structures from the symbol generation circuit 20 and the symbol set memory 21, but the reference waveform generation circuit 50 and the symbol generation circuit 20, Waveform set memory 51 can also be configured to be combined with symbol set memory 21.

In the example shown in Figure 3, in order to make it easier to understand, there are only a few types of waveform pieces, and the address and position scales are extremely coarse, but if necessary, the types can be increased and the scales What can be done in detail is
it is obvious.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, even in a real-time oscilloscope, the reference signal can be displayed on the oscilloscope tube at the same time as the measured signal. It has become possible to make extremely efficient and accurate pass/fail judgments in production lines and inspection processes.

Therefore, the effects of the present invention are extremely large.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing one embodiment of the present invention, FIG. 2 is a specific circuit configuration diagram of the reference waveform generation circuit shown in FIG. 1, and FIG. FIG. 4 is a waveform diagram illustrating the operation of the circuit configuration shown, FIG. 4 is a waveform diagram illustrating a conventional example, and FIG. 5 is a circuit configuration diagram illustrating a conventional example. 11.12... Input terminal 13... Vertical axis preamplifier 14... Vertical axis main amplifier 15... Braun tube 16... Trigger generation circuit 17... Sawtooth wave generation circuit 18... Horizontal Axial amplifier 19...ZN amplifier 20
... Symbol generation circuit 21 ... Symbol set memory 50 ... Reference waveform generation circuit 51 ... Waveform set memory 61 ... Waveform select counter 62 ... Address counter 63 ... Position・Counter 64...Reference waveform memorized...Waveform select switch 2...Address switch 3...Position switches 01 to 107...Waveform piece 20...Signal under test 22...Lower limit reference signal. 121... Upper limit reference signal

Claims (1)

[Claims] 1. Waveform set memory means (51) for storing various waveform pieces constituting a reference waveform that is a reference signal to be displayed together with the signal under test; and a waveform set memory means for storing various waveform pieces in the waveform set memory means A reference waveform display device for a real-time oscilloscope, the reference waveform display device comprising a reference waveform generating means (50) for reading out the various waveform pieces, configuring the reference waveform, and outputting the reference signal. 2. The reference waveform generation means includes waveform selection means (61, 71) for selecting a desired waveform piece from among the various waveform pieces stored in the waveform set memory means; address setting means (62, 72) for setting a desired waveform piece at a desired address; position setting means (63, 73) for setting the selected desired waveform piece at a desired position; configuring and storing the reference waveform by a plurality of the desired waveform pieces having the addresses and positions set;
Reference waveform memory means (6) for outputting the reference signal
4) The reference waveform display device for a real-time oscilloscope according to claim 1, comprising: