JPH05264595A - Digital oscilloscope - Google Patents

Abstract

PURPOSE:To enable overlap displaying of eye patterns and the like by masking the lower bit in the time base counter of a digital oscilloscope of vector display type. CONSTITUTION:Analog input signals are A/D converted with an A/D converter 11, stored once in a data memory 12 and the data are transferred intermittently to an indication memory 13 under the control of a controller 17. For example in a case four times of taken waveforms are transferred to the indication memory 13, every from words are transferred at the first time and every four words with an addition of one address are transferred at the second time. The output of the indication memory 13, after passing a D/A converter 14 and amplifying with a main amplifier 15 are impressed to Y-axis of a CRT 16. A time base counter 18 and a mask register 19 are controlled with a controller 17 and a part of the time base counter 18 output is masked with a gate for mask 20, the output after passing a D/A converter 21 is amplified with a main amplifier 22 and impressed to X-axis of the CRT 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vector display type digital oscilloscope used for observing analog signals and the like.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a conventional digital oscilloscope of this type. In FIG. 4, 1 is an A / D converter to which an analog signal is input, 2 is a data storage memory for storing A / D converted data, and 3 is a data storage memory 2 under the control of the controller 7. A display memory for storing data, 4 is a D / A converter for D / A converting the data read from the display memory 3, 5 is a main amplifier for amplifying the D / A converted data, and 6 is for displaying the data CRT, 7 is a controller, 8 is a time axis counter that generates a time axis address under the control of the controller 7, and 9 is D that D / A converts the output of the time axis counter 8.
A / A converter 10 amplifies the output of the D / A converter 9 to C
This is the main amplifier applied to RT6.

Next, the operation of the above conventional example will be described.
In FIG. 4, the analog input signal is converted into digital data by the A / D converter 1, and then the data storage memory 2
And the stored data is stored in the controller 7
A part or all of the data is transferred to the display memory 3 under the control of. After the transfer is completed, the data read from the display memory 3 is converted into an analog signal by the D / A converter 4, amplified by the main amplifier 5, and then applied to the Y axis of the CRT 6. After the time axis counter 8 is controlled by the controller 7, its output is converted into an analog signal by the D / A converter 9 into a triangular wave, and the main amplifier 10
After being amplified by, it is applied to the X-axis of CRT6.

As described above, also in the above conventional digital oscilloscope, the output of the display memory and the output of the time axis counter are D / A converted, amplified by the main amplifier and applied to the Y axis and X axis of the CRT. This allows the analog input signal to be displayed on the CRT.

[0005]

However, the conventional vector display type digital oscilloscope described above has a problem that the output of the time axis counter is D / A converted as it is, so that the overwriting display cannot be performed.

The present invention is intended to solve such a conventional problem, and an object thereof is to provide an excellent vector display type digital oscilloscope capable of overwriting display.

[0007]

In order to achieve the above object, the present invention provides a mask register controlled by a controller and a masking gate, and masks the lower bits of the output of the time axis counter. The signal in the X-axis direction applied to the CRT is changed from a triangular wave to a stepwise wave.

[0008]

Therefore, according to the present invention, a plurality of Y-axis data can be displayed on the same X-axis address by converting the X-axis signal applied to the CRT into a stepped wave, and even in the vector display system. This has the effect of enabling overwriting display.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, 11 is an A / D converter that receives an analog input signal, 12 is a data storage memory that stores A / D converted data, and 13 is a data storage memory 12 under the control of a controller 17. , A display memory for storing the data of 14, a D / A converter for D / A converting the data read from the display memory 13, a main amplifier 15 for amplifying the D / A converted data, and 16 for displaying the data. CRT, 17 is a controller, 18 is a time axis counter that generates a time axis address under the control of the controller 17, 19 is a mask register that sets a mask bit under the control of the controller 17, and 20 is a mask register 19. A mask gate for masking the output of the time axis counter 18 based on the set mask bit,
Reference numeral 21 is a D / that converts the output of the mask gate 20 into D / A.
A converter, 22 amplifies the output of the D / A converter 21 to C
It is a main amplifier applied to RT16.

Next, the operation of the above embodiment will be described.
In the above embodiment, the analog signal input to the A / D converter 11 is converted into digital data and then stored in the data storage memory 12. Data storage memory 12
The data stored in the display memory 13 is transferred from the controller 17 to the display memory 13 according to the number of times of overwriting. For example, when the captured waveform is overwritten four times, the continuous data in the data storage memory 12 is stored in the display memory 13 every four words, as shown in FIG.
When transferring the second captured waveform to the display memory 13, the data storage memory 12 storing the first captured waveform is incremented by one address and transferred every four words. When the above procedure is similarly performed four times, the display memory 13 is in a state in which the captured waveform is stored four times every four words. Next, "1" is set to the lower 2 bits of the mask register 19.
Is set by the controller 17, and the lower 2 bits of the output of the time axis counter 18 are masked by the masking gate 20. The output of the mask gate 20 is the D / A converter 2
After being converted into an analog signal by 1, it is amplified by the main amplifier 22 and applied to the X axis of the CRT 16. At this time,
By masking the lower bits of the output of the time-axis counter 18, the signal applied to the X-axis of the CRT 16 changes from a triangular wave when not masked to a stepped wave, and when combined with the Y-axis signal, four times of captured waveforms are obtained. Each data will be displayed on the same X-axis address. This state is shown in FIG.

As described above, according to the above embodiment, the number of lower bits of the time axis counter 18 to be masked is 2,
There is an advantage that the overwriting of the captured waveforms 4, 8 ... Times can be realized by the vector display method. If the mask is not used, the normal vector display is used.

[0012]

As is apparent from the above-described embodiment, the present invention provides a mask register controlled by a controller and a masking gate, and masks the lower bits of the output of the time axis counter, thereby applying to the CRT. The signal in the X-axis direction is changed from a triangular wave to a staircase wave, and there is an effect that it is possible to perform overwriting display even in the vector display system. Further, by changing the signal applied to the CRT, there is an effect that it is possible to change the number of times of capturing that can be overwritten and displayed.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a digital oscilloscope according to an embodiment of the present invention.

FIG. 2 is a data transfer diagram from a data storage memory to a display memory in the case of overwriting by four times of data acquisition in the same embodiment.

FIG. 3 is a display screen diagram on a CRT when data is overwritten by four times of data acquisition in the same embodiment.

FIG. 4 is a schematic block diagram of a conventional digital oscilloscope.

[Explanation of symbols]

 11 A / D Converter 12 Data Storage Memory 13 Display Memory 14 D / A Converter 15 Main Amplifier 16 CRT 17 Controller 18 Time Axis Counter 19 Mask Register 20 Mask Gate 21 D / A Converter 22 Main Amplifier

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Aoki 4-3 Tsunashimahigashi, Kohoku-ku, Yokohama-shi, Kanagawa Matsushita Communication Industrial Co., Ltd.

Claims (1)

[Claims] 1. A means for converting an analog input signal into digital data for storage, a means for transferring the storage data to a display memory according to a condition set by a controller, a means for generating a time base address, and the controller. And means for masking the lower address of the time-axis address by setting from the display memory, and means for displaying the display data from the display memory on the vertical axis and displaying the masked time-axis address on the lower address as the horizontal axis. Digital oscilloscope.