JPS6214786B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oscilloscope with an improved delay sweep circuit.

In an oscilloscope with a delayed sweep function, if the sweep time T _A of the main sweep sawtooth wave shown in Fig. 1A includes the sweep time T _B of the delayed sweep sawtooth wave as shown in Fig. 1D, There is no need to terminate the delayed sweep in the middle. However, the first
If the main sweep time T _A ends in the middle of the original delayed sweep time T _B as shown by the dotted line in Figure C, the delayed sweep must be ended midway based on the sweep end pulse shown in Figure 1B.

However, as shown in FIG. 2, even if the sweep end pulse is generated at time _t1 , the delayed sweep actually ends at time _t2 due to the response delay time T.
For this reason, the sweep end pulse jumps into the delayed sweep sawtooth wave generation circuit via stray capacitance, etc., and an abnormal waveform portion as shown by h in FIG. 2C occurs due to the jump. Since the delayed sweep unblanking signal shown in Fig. 2D is generated corresponding to the sweep time of the delayed sweep sawtooth wave, the observed waveform on the screen of a cathode ray tube (CRT) is generated as shown in Fig. 3. An abnormal waveform portion h was displayed, which greatly hindered waveform observation using an oscilloscope. Further, in order to reduce the jump of the sweep end pulse, careful consideration has been required in the design and implementation of the circuit.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an oscilloscope capable of performing a delayed sweep without substantially causing any problems even if an abnormal waveform portion occurs due to a sudden jump when completing a delayed sweep.

To achieve the above object, the present invention includes a main sweep signal generation circuit that generates a main sweep sawtooth wave, a main sweep unblanking signal, and a sweep end pulse of the main sweep sawtooth wave, and delays the sweep end pulse by a predetermined time. a delay circuit that sends out a delayed sweep end pulse; and a delay circuit that generates a delayed sweep sawtooth wave with a delay from the main sweep sawtooth wave; a delayed sweep signal generating circuit configured to terminate a delayed sweep and generating a delayed sweep unblanking signal; a main sweep sawtooth wave obtained from the main sweep signal generating circuit; A sweep sawtooth wave switching circuit that switches between a delayed sweep sawtooth wave and a delayed sweep sawtooth wave according to the sweep mode and sends the signal to the horizontal axis amplifier circuit; and inputs the main sweep unblanking signal and the delayed sweep unblanking signal; supplies the main sweep unblanking signal to the brightness circuit, and in the case of delayed sweep mode, unblanking is performed only during the period in which the unblanking period of the main sweep unblanking signal and the unblanking period of the delayed sweep unblanking signal overlap. an unblanking signal control switching circuit that supplies an unblanking signal for a ranking period to the brightness circuit; The present invention relates to an oscilloscope capable of delay sweep, characterized in that the timing is set to be after the end of the unblanking period of the unblanking signal.

According to the above invention, in the delayed sweep mode, the delayed sweep unblanking signal is not directly output as an unblanking signal, but the unblanking period is ended in synchronization with the end of the main sweep unblanking period, and the delay circuit is Therefore, the sweep end pulse is delayed and the delayed sweep is ended with this delayed sweep end pulse, so even if an abnormal waveform part occurs due to jump, it will be outside the unblanking period and will not be displayed on the CRT screen. .
Therefore, it is virtually unnecessary to take into consideration the jump of the sweep end pulse at the end of the delayed sweep.
Device design and implementation become easier.

Next, an oscilloscope according to an embodiment of the present invention will be described with reference to FIGS. 3 to 6.

The main sweep signal generation circuit 1 of the oscilloscope shown in FIG. 4 has a main sweep sawtooth wave shown in FIG. 5A, a main sweep unblanking signal shown in FIG.
This is a known time base circuit that generates the sweep end pulse shown in FIG.

The delay circuit 2 is a circuit that delays the sweep end pulse of FIG. 5B generated from the main sweep signal generating circuit 1 by a time T _D as shown in FIG. 5C. The configuration is such that a part of the hold-off signal generation circuit in the sweep signal generation circuit 1 is used.

The delayed sweep signal generation circuit 3 responds to the delayed sweep trigger pulse or the delayed sweep excitation pulse as shown in FIG.
This is a known circuit that generates a delayed sweep sawtooth wave as shown in FIG. 5 and also generates a delayed sweep unblanking signal as shown in FIG. 5E. However, the main sweep end pulse shown in FIG. 5B is not directly used to end the delay, but the delayed sweep end pulse shown in FIG. 5C, which is delayed by the time T _D , is used. Even if the delayed sweep end pulse t shown in _FIG .
The sweep ends at time t ₅ after , and the delayed sweep unblanking period also ends in synchronization with this.

The sweep signal switching circuit 4 is a known circuit that selects and outputs the main sweep sawtooth wave shown in FIG. 5A and the delayed sweep sawtooth wave shown in FIG. 5D, and when the oscilloscope is operated in the main sweep mode. is the fifth
The main sweep sawtooth wave shown in FIG.
supply to.

The unblanking signal control switching circuit 6 has a main sweep unblanking signal shown in FIG. 5F generated from the main sweep signal generation circuit 1 and a delayed sweep unblanking signal shown in FIG. In the main sweep mode, the main sweep unblanking signal shown in FIG.
Delayed sweep unblanking signal in Figure E and Figure 5F
The unblanking signal shown in FIG. 5G is generated in which the unblanking level is the period in which both the main sweep unblanking signal and the main sweep unblanking signal are generated simultaneously.

The vertical deflection plate 9 of the CRT8 has a vertical axis amplifier circuit 1.
0, a horizontal axis amplification circuit 5 is connected to the horizontal deflection plate 1, and a brightness circuit 7 is connected to the control electrode 12.

FIG. 6 is a circuit diagram showing a part of FIG. 4 in detail. As is clear from this drawing, the unblanking control switching circuit 6 is not a mere switching circuit, but an AND gate circuit 1 for obtaining an unblanking signal of G based on the inputs of E and F in FIG.
Contains 3. Switches 14 and 15 are mode selection switches; switch 14 is turned on in the main sweep mode, and switch 15 is turned on in the delayed sweep mode. The sweep signal switching circuit 4 consists of switches 16 and 17,
Switch 16 is turned on in the main sweep mode, and switch 17 is turned on in the delayed sweep mode. The switches 14 to 17 are actually electronic switch circuits using rectifier diodes, and the AND gate circuit 13 is also composed of diodes.

The main sweep signal generation circuit 1 includes a main sweep sawtooth wave and unblanking signal generation circuit 18. The output stage of this circuit 18 includes a pair of transistors 2
Differential amplifier circuit consisting of transistors 0 and 21, transistor 2
1, an inverter 22, etc. are provided, and the sweep end pulse shown in FIG. 5B is formed. The delay circuit 2 is configured to also serve as a part of the hold-off signal generation circuit, and includes flip-flops 23 and 24, transistors 25, comparators 26 and 27, and an inverter 2.
8, a capacitor 29, etc., and generates the delayed sweep end pulse shown in FIG. 5C on the output line of the capacitor 29.

The delayed sweep signal generation circuit 3 includes a delayed sweep sawtooth wave and unblanking signal generation circuit 30, a delay pick-off comparator 31, flip-flops 32, 33, etc., and the delayed sweep time T _B ends within the main sweep time T _A. In this case, the sawtooth wave and unblanking signal are generated regardless of the delayed sweep end pulse shown in FIG. 5C, but in the case of the time relationship as shown in FIG. 5, the signals shown in FIGS. 5D and E are generated.

As is clear from the above, according to this example,
Figure 5D by the delayed sweep end pulse of Figure 5C.
As shown in the figure, even if an abnormal waveform part h occurs due to jump, the unblanking signal disappears at time t ₃ before this and reaches the bright line erasure level, so the abnormal waveform part h is not displayed on the CRT screen. and will not interfere with measurement. Further, since the bright line erasure state is entered at the same time as the main sweep time T _A ends, the delay time T _D by the delay circuit 2 can be set relatively freely. Therefore, the design and implementation of the circuit device is facilitated.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto and can be further modified. For example, the unblanking signal control switching circuit 6 may be configured to be separated into a gate circuit for obtaining an unblanking signal in the delayed sweep mode and a switch circuit for mode switching.

[Brief explanation of the drawing]

1, 2, and 3 are waveform diagrams showing the states of various parts in a conventional oscilloscope, FIG. 4 is a block diagram showing an oscilloscope according to an embodiment of the present invention, and FIG. and A to G in Figure 6.
FIG. 6 is a circuit diagram showing a part of the oscilloscope shown in FIG. 4 in more detail. In the symbols used in the drawings, 1 is a main sweep signal generation circuit, 2 is a delay circuit, 3 is a delayed sweep signal generation circuit, 4 is a sweep signal switching circuit, and 6 is an unblanking signal control switching circuit. .

Claims (1)

[Scope of Claims] 1. A main sweep signal generation circuit that generates a main sweep sawtooth wave, a main sweep unblanking signal, and a sweep end pulse of the main sweep sawtooth wave, and a delayed sweep that delays the sweep end pulse by a predetermined period of time. a delay circuit that sends out a termination pulse; and a delay circuit that generates a delayed sweep sawtooth wave with a delay from the main sweep sawtooth wave, and when the delayed sweep termination pulse is generated during a sweep using the delayed sweep sawtooth wave, the delayed sweep a delayed sweep signal generation circuit configured to terminate and generate a delayed sweep unblanking signal; the main sweep sawtooth wave obtained from the main sweep signal generation circuit; and the delayed sweep sawtooth wave obtained from the delayed sweep signal generation circuit. a sweep sawtooth wave switching circuit which switches the wave according to the sweep mode and sends the wave to the horizontal axis amplifier circuit; the sweep unblanking signal and the delayed sweep unblanking signal are input; An unblanking signal is supplied to the brightness circuit, and in the case of delayed sweep mode, only the period in which the unblanking period of the main sweep unblanking signal and the unblanking period of the sweep unblanking signal overlap is the unblanking period. an unblanking signal control switching circuit for supplying a ranking signal to the luminance circuit; and an unblanking signal obtained from the unblanking signal control switching circuit when the delayed sweep end pulse is generated in the delayed sweep mode. A delayed sweepable oscilloscope, characterized in that the delay sweep is set to be later than the end point of an unblanking period.