JPH0458908B2 - - Google Patents

Description

[Detailed description of the invention] (Technical field of invention) The present invention relates to an electrical signal display circuit.

(Background of the Invention) When adjusting various types of equipment, it often becomes necessary to display two signals on one screen in an overlapping manner with the time axes aligned.
For example, there is a case where it is necessary to superimpose the reference time signal waveform on the observed signal waveform and display it on a single screen, such as the CRT screen of an oscilloscope, and adjust the equipment while checking the timing of the observed signal.
In this case, it is common to use a two-phenomenon oscilloscope. However, in the case of automatic control equipment, etc., there are many signals that must be observed simultaneously, and if all of these signals are to be observed using a two-phenomenon oscilloscope, a large number of two-phenomenon oscilloscopes will be required. This has the disadvantage that a large number of equipment must be prepared for the adjustment, especially when adjustment work is performed after installing automatic control equipment. Therefore, in the above case, it is necessary to reduce the number of observed signals. Further, in a two-phenomenon oscilloscope, the delay times of the respective channels do not exactly match, so accurate timing adjustment is impossible. Furthermore
When displaying in CHOP mode, the two signals are displayed alternately, albeit at short time intervals, so it is not possible to display both signals strictly at the same time, making it impossible to observe exact timing.

For example, by superimposing the reference time signal waveform on the observed signal waveform, you can display it on a single screen, such as on an oscilloscope.
If you need to adjust the equipment while checking the timing of the observed signal by displaying it on a CRT screen, you can consider simply superimposing an impulse-like timing pulse on the observed signal and displaying it.
This has the disadvantage that when the observed signal changes slowly and is displayed with a long time axis, the impulse-like timing pulse becomes thin and cannot be seen visually. Therefore, it is naturally possible to use a pulse-like timing pulse having an appropriate time width as the impulse-like timing pulse. In this case, the timing can be confirmed, but since the voltage of the timing pulse is usually constant, when the level of the observed signal is low and the level is enlarged and displayed on the oscilloscope, the part where the timing pulse is superimposed will be outside the oscilloscope's display screen. This has the disadvantage that it is impossible to observe the entire waveform.

(Object of the Invention) The present invention has been made in view of the above points, and provides a display circuit that uses one channel of an oscilloscope to overlay two signals with their time axes accurately aligned and display them on one screen. With the goal.

(Summary of the Invention) The technical point of the present invention is to display a signal obtained by superimposing a high-frequency signal synchronized with an observed signal using one channel of an oscilloscope.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention, in which 1 is a reference time generating circuit, 2 is a pulse generating circuit, and these two circuits constitute a reference pulse generating circuit 3. 4 is a high frequency signal generation circuit, 5 is an AND circuit, 6 is a signal to be observed, 7 is an analog addition circuit, and 8 is a display signal.

FIG. 2 is a diagram of signal waveforms at various points in the block diagram shown in FIG. The signal waveform obtained by ANDing the signal and B, D shows the waveform of the observed signal 6, and E shows the waveform of the display signal 8 which is the output of the analog adder circuit 7.

As is clear from FIGS. 1 and 2, the observed signal 6 has a waveform with a peak as shown in FIG. If you want to match the time, the output 8 of the analog adder circuit 7 is input to one channel of the oscilloscope and is displayed as a waveform as shown in Figure 2E, so operate the adjustment means while looking at the oscilloscope screen. The signal waveform of the high-frequency signal generating circuit 4 may be superimposed on the waveform of the observed signal 6 starting from the peak thereof. Of course, the display circuit of the present invention can be used in various ways in addition to the above adjustment work.

The display circuit according to the present invention may be incorporated into the circuit of a device, or may be constructed separately and used as an adapter.

In the embodiment, the output pulse of the pulse generation circuit 2 rises due to the output of the reference time generation circuit 1, but the output pulse of the pulse generation circuit 2 may fall.

Furthermore, the frequency of the output signal of the high-frequency signal generating circuit 4 needs to be set higher than the frequency of the observed signal 6 to such an extent that it can be identified on the screen of the oscilloscope. Incidentally, the applicant of this application has observed signal 6.
is 5Hz, and the output signal of high frequency signal generation circuit 4 is 5K.
Good discrimination was possible when using Hz.

(Effects of the Invention) As described above, the present invention uses one channel of an oscilloscope to display a signal in which the observed signal and a high-frequency signal synchronized with a timing signal are superimposed, so that the time axes are accurately aligned. It is possible to obtain a display circuit that displays the signals on one screen by overlapping them, and the timing of the observed signal can be observed strictly. Furthermore, if the observed signal changes slowly, it is easy to check the timing even if the time axis is extended and displayed, and if the level of the observed signal is low and the output level is enlarged, the superimposed high-frequency signal The entire waveform of the observed signal can be observed depending on the shape of the waveform on either the upper or lower side of the envelope.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a signal waveform diagram at various points in the block diagram shown in FIG. Explanation of symbols of main parts, 3... Reference pulse generation circuit, 4... High frequency signal generation circuit, 5... Logical product (AND) circuit, 6... Signal to be observed, 7... Analog addition circuit.

Claims (1)

[Claims] 1. A reference pulse generation circuit representing a time reference; a high frequency signal generation circuit; an AND circuit inputting the output of the reference pulse generation circuit and the output of the high frequency signal generation circuit; and the logic. A signal display circuit that includes an analog addition circuit that receives the output of a product circuit and an observed signal as input.