JPS60188856A - Oscilloscope - Google Patents

Abstract

PURPOSE:To measure a voltage from the grounding level to an optional point of a waveform by indicating the grounding level together with the waveform in an oscilloscope to facilitate the confirmation of the grounding level, further indicating a DELTAV cursor. CONSTITUTION:An input terminal 1 of a signal is connected to an amplifier through a switching circuit 2, and a signal switching device 4 switches the output of an amplifier 3 and a memory circuit 6 alternately and drives a CRT. A controlling circuit 7 switches the circuit 2 intermittently by a controlling signal (c). Grounding level is stored in a sample hold circuit 8 through the amplifier 3, and A/D converted 9. Converted digital value is D/A converted 11 through an adder circuit 10 and applied to the switching device 4. At this time, the output (h) of a DELTAV setting circuit 12 is supplied to the circuit 10 intermittently for a fixed time, and the waveform different in level corresponding to potential difference from the grounding level to DELTAV cursor is obtained. Further, the voltage from the grounding level to an optional point of a waveform can be obtained by changing the value fed to the circuit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an oscilloscope that displays a ground level along with a waveform on a tube surface.

(Prior art and its problems) Conventional oscilloscopes cannot display the ground level at the same time as the waveform. Therefore, when observing a meaningful signal at the ground level (for example, a logic signal), set the input coupling switch to "rGND".

The bright line was aligned at a certain position on the tube surface, and then a one-man coupling switch was set to IJO coupling, and the voltage from the ground level was measured. Therefore, if the emission line position was moved during observation of the IMU, ground level information would be lost, and the above-mentioned operation had to be performed each time the emission line position was moved.

Further, a cursor function for measuring the total potential difference between two points of a waveform displayed on a conventional screen is generally known. When trying to measure temperature and pressure from the ground level to any point on the waveform using this cursor function, use one of the cursors (
This was done by aligning the reference cursor) with the ground level and the other cursor (Δ cursor) with an arbitrary point on the waveform. In this case as well, the reference cursor had to be adjusted to the ground level in order to move the position 1d, which was a cumbersome operation.

(Purpose) In order to solve these drawbacks, the present invention aims to display the ground level at the same time as the waveform, display a Δ cursor, and measure the voltage from the ground level to any point on the waveform. .

(Embodiment) The present invention consists of a switch circuit that switches between an input signal and ground, a sample hold circuit that is synchronized with this switch circuit, and an A/L circuit that A/D converts the signal of the sample/hold circuit.
) An adder circuit connected to the output of the converter circuit and a 1)/A converter circuit connected to the adder circuit make it possible to display a Δ cursor that measures the voltage up to an arbitrary point on the waveform along with the ground level. .

The principle of this invention will be explained below using the block diagram of FIG. 1 and the waveform diagram of FIG. 2.

In FIG. 1, a signal input terminal 1 is connected to an amplifier 3 via a switch circuit 2, and the output of the amplifier 3 is connected to a signal switch 4 and a memory circuit 6.

The signal switch 4 alternately switches the outputs of the amplifier 3 and the memory circuit 6 to drive the cathode ray tube. The switch circuit 2 signal changer 4 and memory circuit 6 are connected to a control circuit 7 and operate under the control thereof. Furthermore, the memory circuit 6 includes a sample and hold circuit 3. A/i) Converter 9° adder circuit IO, set the kernel position at any position on the cathode ray tube. ΔV setting circuit 12. and an Ll/Am converter 11.

In the above connection, the control circuit 7 receives the control signal (Fig. 2C)
9 and intermittently switches the switch circuit 2 to the ground side. The ground level of the waveform bK in FIG.
is converted into a digital value. Note that FIG. 2a is the waveform of human power No. 1d. The converted ground level digital value passes through the adder circuit 10, is converted into an analog value by the /A converter 1, and is applied to the signal switch 4. At this time, by intermittently applying the output of the ΔV setting circuit 12 to the adding circuit IO for a certain period of time, the waveform shown in FIG. 2d is obtained. The step in the waveform in Figure 2 d is at the ground level (
Corresponds to the potential difference from b) to the ΔV cursor.

It is something that

The signal switch 4 alternately switches the output (FIG. 2 d) and the input signal (FIG. 2 a) of the memory circuit 6 and creates a signal (FIG. 2 C) in which they are combined. In the example shown in FIG. 2, the time ratio between the input signal a and the output d of the memory circuit 6 is 2:1. By applying this signal to the cathode ray tube 6, the waveforms shown in FIG. Therefore, by changing the haze applied to the Δ■ setting circuit 12 and adjusting the Δ kernel position to an arbitrary location on the waveform f, it is possible to set the voltage from the ground level g to an arbitrary point on the waveform.

FIG. 3 shows a detailed circuit diagram of an embodiment of the present invention. The input terminal 1 is connected to the amplifier circuit 3 through a switch circuit 2 which is controlled by an ILT control signal 35 from a microcomputer circuit 36. As an example of the amplifier circuit 3, a differential amplifier circuit is used. The differential output of amplifier circuit 3 is transistor 1
3 a, b l 17albl resistor 20a.

It is connected to the emitters of transistors l 21a and 21b via 20b. Transistors 212, 2
The collector of b'1. It's been done.

One end of the remaining resistor 23a is connected to the plus input of the amplifier 25 and ground via the resistor 24a. resistance 23
The remaining end of b is connected to the negative input of amplifier 25 and resistor 2.
4b to the output terminal of the amplifier 25.

The output 'ifA' of the amplifier 25 is connected to the plus input of the comparator 26 and also to the sample and hold circuit 8. Here, the sample and hold circuit 8 is composed of a switch element 27 and a hold capacitor 28, which are controlled by a control signal 29 from a microcomputer circuit 36. The output of the sample and hold circuit 8 is connected to the negative input of the comparator 26. The output of the comparator 26 is connected to a microconbeater circuit 36 as a comparison result signal 30. The D/A converter 11 is connected to the micro converter circuit 36, and the D/A converter 1
The output of 1 is connected to the base of transistor 33b.

The collector of the transistor 33b is connected to the base of the resistor 34b' (through the transistor 17I) and the transistor 13b.
connected to the collector connection point. transistor 3
The emitter of 31) is connected to the emitter of transistor 33a and current source 32. The current source 32 is controlled by a control signal 31 from a microconbeater circuit 36. The control signal 31 is also connected to the differential amplifier circuit 3, and outputs or cuts the signal depending on the control signal 31. The midpoint of the variable resistor 39 is connected to the amplifier 3 and
Both ends are connected to a positive power source W■+ and a negative power source ■-, respectively. Both ends of the variable resistor 37 are connected to the positive power source V+ and the negative power source V-, respectively.

Its midpoint is connected to the analog input of the microconbeater circuit 36. In addition, the microconbeater circuit 36 is equipped with a vertical axis deflection sensitivity switch (
(not shown) is connected to the switch 38.

As described above, the embodiment shown in FIG. 3 is a more realistic circuit based on the principle diagram shown in FIG. 1. That is, one example is the A/Di conversion circuit 9 shown in FIG. and D/
In order to configure the A conversion circuit 11 with a small number of parts, J)/
The A conversion circuit 11 is operated in a mode corresponding to the D/A conversion circuit 11 shown in FIG.
By applying the voltage to the comparator 2G via the output path of passl shown in FIG. 3 of the transfer circuit 11, the signal A shown in FIG.
/ J) The operation sound corresponding to the conversion circuit 9 is being made.

Furthermore, in FIG. 3, the addition circuit 10 and the .DELTA.V setting circuit 12 shown in FIG. 1 are realized on software by a microcomputer circuit 36.

1. In Fig. 1, ground level detection is taken from the output of amplifier 3, whereas in Fig. 3, ground level detection is taken from the output of cathode ray tube 5.
The signal line driving the deflection plate is taken out,
It is better to take this out from a deflection plate with a high signal level.
This is because the /N ratio can be improved and the amplifier circuit is simpler.91 They are essentially the same.

The control circuit 7 shown in FIG. 1 is realized on software by the microcomputer circuit 36 in FIG. 3, and the signal switch 4 is realized by the transistor 33a in FIG.
, 33b and current source 32. 4 by differential amplifier circuit 3
14 have been completed. As described above, it is obvious to those skilled in the art that the principle diagram shown in FIG. 1 can be developed into the embodiment shown in FIG. 3.

In Fig. 3, the signal marked 11 at input terminal 1 in connection 71 is the switch circuit 2? The signal is applied to the amplifier circuit 3 via 1-. The signal applied to input terminal 1 in circuit 3 is converted into a differential signal and transmitted to transistors 13a and 13b.
(1) Power is applied to the emitter. Transistor 13a
, 13b is amplified by the transistor 17a.
, 17b.

111. which is sufficient to drive the vertical deflection plate of the cathode ray tube 5 by means of 21a and 21b. The pressure is amplified. CI] The resistor 39 determines where on the cathode ray tube 5 the waveform is displayed.

Next, the control signal 35 from the microconbeater circuit 36 is
is the output, and the switch circuit 2 is grounded from the signal side.
Switch to lK. Flowcharts of the operation of this microconbeater circuit 36 are shown in FIGS. 4 and 5. The signal applied to the differential amplifier circuit 3 is at ground level.

A ground level voltage is applied to the deflection electrode of the cathode ray tube 5. At this time, the amplifier 25 is connected to the resistor 23a 1231) +
248+24b forms a differential amplifier circuit (14), so the output of the amplifier 25 is the differential voltage applied to the two deflection electrodes of the cathode ray tube 5.The microconbeater circuit 36 receives the control signal. 29 is output, and this difference electric month -
is memorized in the hold capacitor 28. The voltage stored in this hold capacitor 28 is a voltage corresponding to the ground level on Brown %H5. Next, the microconbeater circuit 36 outputs the control signal 31 and the current source 3
2 is turned on, and the output of the differential amplifier circuit 3 is turned off. 'When the turtle θtUrt32 is turned on, the transistors 33a and 331) become active and L)/A
The output of the converter 11 is sent to the cathode ray tube 5 through transistors 17a, 17b and transistors 21a, 21b.
is guided to the deflection electrode of the differential amplifier 6 and is then applied to the comparator 26.

The comparator 26 compares the output of the JJ/A converter 11 with the voltage 1,1 below the ground level previously stored in the fj<- field capacitor 28, and sends a comparison result signal 30i to the microcomputer circuit 36. The microcontroller circuit 36 changes the value sent to the 1)/A converter 11 and reads the ground level stored in the hold capacitor 28. At this time, 1)/A converter 11. Comparator 26 and microcomputer circuit 36 form the well-known interdigital comparison type A/l) conversion circuit.

As a result, the micro combi coater circuit 36 is connected to the cathode ray tube 5.
The ground level of can be known as numerical data nlG. After a series of these processes, the microconbeater circuit 36 returns the geoscilloscope to the normal waveform display mode by releasing the control signals 31 and 39. After writing the ground level data mG to the D/Ag converter 11.

By intermittently turning on and off the flj control signal 31, it is possible to display the ground level on the screen together with the waveform. A/1 mentioned earlier still remains after a certain period of time.
] By updating the ground level data InG in the conversion mode, the variable resistor 39 is set to 1 and the bright line position on the tube surface is changed. 11- It is possible to automatically follow the ground level even when moving.

In the present invention, in addition to the ground line display described above, by using a bell, the value obtained from the voltage value of the variable resistor 37 -i<N, and the Glanton bell data Ill
By outputting G alternately to the /A converter 11 and +fli control (turning on the g signal 31 and turning on 6, the /J signal in Fig. 2 is output.
Two cursors g and g' can be drawn on the screen in a manner similar to that of a screen. At this time, the ground level data ma is J) A
The cursor obtained by outputting it to the converter 11 is outputted as a result of the reference cursor (1, 1). Δ at any point of the waveform drawn on 5
When you move the cursor gold, the value difference between the reference cursor and the Δ cursor is −j−force, which is N −m ayoC(1,1)
The value V from the ground level at any point on the inverse waveform according to the formula
-m a ■a-4oo × (deflection sensitivity) (1, 2) (Deflection sensitivity is obtained from switch 38) (400 is 1 d above the tube surface)
The flowchart of the ground level display described above is shown in Fig. 4, and Fig. 5 shows the flowchart of the above-mentioned ground level display.
-7Je of Char-1.

(Effects) With the oscilloscope according to the present invention, the ground level can be measured along with the waveform, making it easier to check the ground level, which used to be a tedious task.

Furthermore, it is possible to measure voltages from ground level to any point on the waveform.

1) In the present invention, the detection of the ground level can be taken out from the downstream stage of the signal switch, that is, from the signal level control circuit.2 Various modifications can be made without departing from the gist of the present invention. It will be obvious to those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the principle of the present invention, and FIG. 2 is a diagram with the waveforms at the troughs omitted. Figure 3 is a circuit diagram of the example of "Ki-ni ψ", Figure 4 is a flowchart when displaying the ground level, and Figure 5 is input to the bf diagram when measuring the voltage from the ground level to the Δ cursor. Terminal, 2: Switch circuit, 3
:amplifier. 4: Signal switching circuit, 5 Ni cathode ray tube, (i: Memory 11J
7: Control circuit, 8: Sample and hold 1 circuit. 9: A/Di converter, 1o: addition circuit fl15. 11:
1) /1xihou times m, 12: A V V sis!
, 13a, 13b, 17a, 17b. 21a, 21b, 33a, 33b: Transistor +
14115116119118a + 18b, 2
0a +20b +22a +22b +23a +2
3b, 24a +24b +34a. 34b: Resistor, 25: Amplifier, 26: Comparator, 27: Switch, CH element, 28: Hold, capacitor, 38: Deflection sensitivity setting switch, 37.39: Variable resistor. 32: Current source, 31: Control signal (ground level/V type switching), 35: Control signal (GNI)/signal), 30: Comparison result signal, 29: Control signal (ground sample) Yoshihito Daitomo, Attorney ± 1 % Hashi Akira, <7 'h゛,.

Claims (1)

[Claims] 9. Switch means for switching between the input signal side and the ground side; Storage means for storing the ground level when the switch means is on the ground side; 9. Cursor level setting means corresponding to the cursor position on the display screen; and 2. Display screen vertical axis deflection. An oscilloscope comprising switching means for alternately switching the human power signal, the ground level, and the cursor level.