JPH0648430Y2 - Multi-phenomenon oscilloscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an improvement of a channel switching circuit used in an oscilloscope having a single-beam cathode ray tube.

[Outline of device]

The present invention prevents erroneous recognition of a waveform that may occur in the alternate sweep mode.

The present invention controls a reference signal generating means and a signal from the reference signal generating means by a signal from a sweep gate means (gate).
This means is used as the channel switching signal in the alternate mode.

As a result, even in the alternate mode, the channel is not switched for each retrace line as in the conventional case, and the channel is switched during the retrace period after the same channel is swept and displayed a plurality of times. For this reason, misidentification of the waveform does not occur.

[Conventional technology]

 A block diagram of the conventional method is shown in FIG.

1'is a reference signal generator, 3 is a sweep gate circuit, 5 is a switch circuit, 6 is a channel switching circuit, and 7 is a sweep generator circuit.

The cathode ray tube used for the oscilloscope is generally a single beam, and the state of the tube surface at a certain moment is only a bright spot. However, the human eye has an afterimage of several tens of milliseconds, which allows the movement of bright spots to be recognized as a continuous waveform. Therefore, two waveforms can be viewed at the same time by quickly switching between the two signals (CH1, CH2) and performing the same sweep.

There are two methods to switch this channel: CHOP and ALT.

CHOP: A fixed period (eg 5) regardless of the sweep
μsec) switching method. For this reason, a switching point occurs in the tube surface, and in the fast sweep range, smoothing due to the afterimage of the eye is insufficient and the dashed line may appear to move.

Alternate (ALT): A method of switching channels during the blanking period of the sweep. Therefore, the slower the sweep, the more difficult it becomes to compare the two waveforms.

As described above, the alternate mode is used in the measurement in the fast range, but the conventional method may cause the following problems because the channel is switched every sweep. This is the fifth
It is shown in FIG. 6, FIG. 7, FIG.

FIG. 5 shows a flip-flop which is the circuit under test. FIG. 6 shows each waveform of the flip-flop 8 and the sweep output waveform 17.

From the general side, in this case, the fast sweep range is set, so the alternate mode is set, and the trigger is applied by the signal with an early timing, the input waveform 9, so that the rising portion can be seen. When the input waveform 9 is input to CH1 and the output waveform 10 is input to CH2 and displayed on the screen, there are two types of screen display, the screen display of FIG. 7 and the screen display of FIG. 8, depending on the switching timing of the channel. Whether the screen display in Fig. 7 or the screen display in Fig. 8 is uncertain due to the timing of signal addition, the timing of oscilloscope settings, etc., and the measured waveform is misidentified. There was an occasion.

[Problems to be solved by the device]

In the above-mentioned conventional technique, there is a drawback that the waveform is erroneously recognized in the alternate mode.

In order to solve these drawbacks, the present invention solves these drawbacks, for example, even when measuring a circuit as shown in FIG.
The purpose is to display the existence on the tube surface.

[Means for Solving the Problems]

The present invention comprises a second reference signal generating means for generating a signal having a period longer than the period in the chop mode, and means for controlling (gate) the signal from the reference signal generating means with the signal from the sweep gate means. Yes, in alternate mode,
This signal is used as a channel switching signal.

[Action]

As a result, even in the alternate mode, the channel is not switched for each retrace line as in the conventional case, and the channel is switched during the retrace period after the same channel is swept and displayed a plurality of times.

Therefore, if the oscillation cycle of the second reference signal generating means is selected so as not to cause a flicker on the display, the conventional misrecognition of the waveform does not occur.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is a first reference signal generator for chop sweep reference, 2 is a second reference signal generator for alternate sweep reference, and both reference signal generators generate signals for switching channels. Three
Is a sweep gate (SWP GATE) circuit whose output signal is used as the input of a sweep generator to generate a sawtooth wave and as a channel switching signal during alternate sweep. 4 is an AND circuit, and 5 is a switch circuit, which selects chop sweep or alternate sweep. 6 is a channel switching circuit, 7 is a sweep and generator (SWP GEN) circuit, which generates a sweep wave (sawtooth wave) based on the gate signal from the sweep gate circuit. FIG. 2 is a waveform diagram of each part.

The operation of the present invention will be described below.

In the chop mode, the switch circuit 5 is connected to the first reference signal generator 1 as in the conventional case, and the channel switching circuit 6 is switched at a constant cycle (for example, 5 μsec) regardless of the sweep. Therefore, at this time, the channel is switched regardless of the sweep, and the observed waveform is displayed on the surface of the cathode ray tube (not shown).

Next, the operation of the present invention in the alternate mode will be described. The switch circuit 5 is connected to the output of the AND circuit 4. One input of the AND circuit 4 is connected to the sweep gate (SWP GATE) circuit 3, and the other input is connected to the second reference signal generator 2. The second reference signal generator 2 also has a constant period irrespective of the sweep (the oscillation period of the second reference signal generator 2 is longer than that of the first reference signal generator, but for example, the number 10 which cannot be recognized by human eyes).
Within msec. ) Oscillates. The output 12 of the second reference signal generator 2 is input to the AND circuit 4 together with the sweep gate signal 13 from the sweep gate circuit 3. With this AND signal, the channel switching circuit 6 switches channels.
Therefore, the channels are switched in synchronization with the sweep gate signal 13 during the blanking period of the sweep. on the other hand,
Since the period of the second reference signal 12 is longer than the period of the sweep gate signal, the same channel is displayed during this period.

The tube surface display at this time will be described with reference to FIGS. 3, 5, and 6.

Whereas the conventional alternate sweep is switched to CH1, CH2, CH1, CH2 every blanking period, in the present invention, for example, CH1, CH1,
CH1, CH2, CH2, CH2, CH1 ..., so when measured with the measurement circuit shown in Fig. 5, the trigger point and two points are set during the period when the channel switching circuit 6 is setting CH2, for example. Therefore, there are both rising and falling waveforms,
The display on the tube surface is as shown in FIG.

[Effect of device]

According to the present invention, it is possible to eliminate the erroneous recognition of the observed waveform, which has been conventionally caused by switching the channel for each sweep.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a waveform chart of each part in the embodiment of the present invention, FIG. 3 is a waveform chart of a tube surface in the embodiment of the present invention, and FIG. An example block diagram, FIG. 5 is a measurement circuit diagram, FIG. 6 is a waveform diagram of each part of the conventional example, and FIGS. 1: Reference signal generator 1, 2: Reference signal generator 2, 3: Sweep gate circuit, 4: AND circuit, 5: Switch circuit, 6: Channel switching circuit, 7: Sweep generator circuit.

Claims (2)

[Scope of utility model registration request] 1. A reference signal for generating a signal having a period longer than the period in the chop sweep mode in the alternate sweep mode of a multi-phenomenon oscilloscope using a single-beam cathode ray tube having an alternate sweep mode and a chop sweep mode. Generating means, sweep gate means for controlling the timing of generating a sawtooth sawtooth wave for displaying an observed waveform on the cathode ray tube surface, and a signal from the reference signal generating means for thinning the signal from the sweep gate means. It is characterized in that it has gate means for controlling and channel switching means for switching channels by gate signals thinned out by the gate means, and the thinning control allows the same channel to be switched after displaying the same channel a plurality of times. The multi-phenomenon oscilloscope. 2. A multi-phenomenon oscilloscope having a single-beam cathode ray tube, a switching circuit for switching a display channel of an observed waveform, a sweep gate circuit for generating a sweep gate signal, and a channel switching signal for a chop sweep. A first reference signal generator, a second reference signal generator for generating a signal having a period longer than that of the first reference signal generator, the second reference signal generator and the sweep gate A gate circuit that creates a channel switching signal during alternate sweep by ANDing the signal, a channel switching signal during alternate sweep of the gate circuit, and a channel switching signal during chop sweep of the first reference signal generator. A multi-phenomenon oscilloscope, comprising: a switch that selects one of them and supplies it to the switching circuit.