JPH01318967A - Digital waveform displaying apparatus - Google Patents

Abstract

PURPOSE:To adjust a bright line to a desired vertical position quickly by sending an output signal from a waveform memory under the state wherein an analog input signal is outputted from a switch, and sending an output signal from an offset control circuit under the state wherein a ground potential is outputted. CONSTITUTION:An offset control circuit 8 controls a data switch 5 so that a signal Sod which is applied from the offset control circuit 8 is outputted in accordance with a switching signals Ss' based on a status judging signal Ss under the state wherein a switch 1 selects a ground potential Vg. Then, the offset data Sod without fluctuation in 1 LSB due to digitalization are added to a display control circuit 6. A bright line A which is a horizontal straight line is displayed on a display device 7. The bright line a is moved up and down on the display device 7 by the adjustment of a position control signal Sp. The offset data Sod which are added into an amplifier 2 from the offset control circuit 8 are also changed with the position control signal Sp.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a digital waveform display device,
More specifically, it relates to improvements in ground potential display.

(Prior Art) A type of digital waveform display device configured to display a waveform by selectively driving a plurality of two-dimensionally arranged display pixels according to digitally sampled waveform display data. There is.

For example, in the case of a CRT, a rask scan display is performed in which an electron beam is sequentially scanned from the lower left to the upper right of the screen, and the fluorescent surface of the CRT emits light only at the position where the waveform is displayed. Here, since the waveform is displayed only when the fluorescent surface of the CRT is irradiated with an electron beam,
The same waveform data is stored in memory and
Display is repeated 0 times.

By the way, in such a device, when adjusting the vertical display position of the waveform, the input signal is set to the ground potential and the CR
A zero-level bright line is displayed on the screen of the T, and the display position is changed by vertical position adjustment.

(Problem to be solved by the invention) However, even if the input signal is at ground potential, fluctuations in ILSB will remain because digital sampling is performed, and the bright line will not be a straight line. It is difficult to quickly adjust to vertical position.

The present invention has focused on these points, and its purpose is to provide a digital waveform that can quickly adjust the bright line to a desired vertical position without being affected by 1 LSB fluctuation when the input signal is set to ground potential. The purpose of this invention is to provide a display device.

(Means for Solving the Problems) The digital waveform display device of the present invention includes: a changeover switch that selectively outputs an analog input signal and a ground potential; an amplifier that amplifies the output signal of the changeover switch; A digitization circuit that converts an output signal into a digital signal, a waveform memory that stores the output signal of this digitization circuit, an offset control circuit that outputs offset data to be given to the analog input signal, and this offset control circuit. a D/A converter that converts offset data output from the converter into an analog signal and applies it to the amplifier; an output signal of the waveform memory and an output signal of the offset control circuit are added; and an analog input signal is output from the changeover switch. A data switch that sends out the output signal of the waveform memory when the ground potential is output, and an output signal of the offset control circuit when the ground potential is output; A display device in which a plurality of display pixels are selectively driven.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a changeover switch that selectively outputs an analog input signal AQ and a ground potential 9. Output signal S of this changeover switch 1.

is added to amplifier 2. The amplifier 2 receives an analog offset signal SO to be applied to the analog input signal A11-1 from the offset control circuit 8 via the D/A converter 9.
A is also added. These analog input signals A in
The output signal Sa of the amplifier 2 to which the
d4 will be converted. 4 is a waveform memory that stores the digital signal Sd output from the digitization circuit 3. 5 is a data switch for selecting data S2 to be output to the display control circuit 6, to which the output signal sd- of the waveform memory 4 and the output signal SOd of the offset control circuit 8 are applied, and the state of the changeover switch 1 is determined. According to the switching signal Ss- based on the signal S9, when the analog input signal Arn is output from the changeover switch 1, the output signal sd- of the waveform memory 4 is sent out, and when the ground potential V9 is outputted, the offset control circuit 8 is sent out. The output signal SOa is sent out.

Note that a position control signal Sp for instructing adjustment of the vertical position of the bright line is applied from the outside to the offset control circuit 8. 7 is a CRT in which multiple display pixels are arranged two-dimensionally.
This display device is selectively driven according to the image signal Sυ output from the display control circuit 6.

The operation of the apparatus configured in this way will be explained using FIG. 2.

In the offset control circuit 8, the changeover switch 1 is set to the ground potential ■
9 is selected, the data switch 5 is controlled to output the signal SOa added from the offset control circuit 8 in accordance with the switching signal Ss- based on the state determination signal SS.

As a result, the display control circuit 6 receives the offset data Soa, which has no I LSB fluctuation associated with conventional digitization processing, and the display 7 displays a horizontal straight line as shown in FIG. The n-line A will be displayed.

This bright line A is displayed on the display 7 according to the adjustment of the position control signal Sp.
Move up and down. The offset data Sod applied from the offset control circuit 8 to the amplifier 2 via the D/A converter 9 also changes according to the position control signal Sp.

On the other hand, when the changeover switch 1 selects the analog input signal Ajn, the offset control circuit 8 outputs the signal Sd'' added from the waveform memory 4 in accordance with the switching signal Ss- based on the state determination signal Ss. The data switch 5 is controlled.As a result, the display 7 displays a waveform B based on the waveform data as shown in FIG. 7 to move up and down.

With this configuration, it is possible to quickly adjust the vertical position of the bright line with the input signal at ground potential without being affected by changes in the LSB in the digitizing circuit 3 as in the conventional case. can.

In the above embodiment, the offset data Sod outputted from the offset control circuit 8 as horizontal bright line data was given directly to the display control circuit 6, but the resolution and offset of the data Sd° outputted from the waveform memory 4 When the resolutions of the data SOa are different (generally, the resolution of the offset data Soa is higher than the resolution of the data Sd''), the higher resolution may be rounded to match the lower one.

In addition, amplifier 2. If the DC error in the digitizing circuit 3 is smaller than ±I LSB of the digitizing circuit 3, the configuration shown in Figure 1 may be used, but if the error due to drift etc.
If it is larger than LSB, for example, offset data S
An error correction circuit that adds an error correction amount to od may be provided.

In addition, the display device is not limited to CRT, but also LCD, L
It may be ED, EL, etc.

(Effects of the Invention) As explained above, according to the present invention, when the input signal is set to the ground potential, the bright line can be quickly adjusted to a desired vertical position without being affected by fluctuations in I LSB. A digital waveform display device can be realized, and the p effect is large in practice.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the operation of FIG. 1. DESCRIPTION OF SYMBOLS 1... Selector switch, 2... Amplifier, 3... Digitization circuit, 4... Waveform memory, 5... Data switcher, 6... Display control circuit, 7... Display device , 8...
Offset control circuit, 9...D/A converter. Figure 1 p Figure 2

Claims (1)

[Claims] A changeover switch that selectively outputs an analog input signal and a ground potential; an amplifier that amplifies the output signal of the changeover switch; and a digitization circuit that converts the output signal of the amplifier into a digital signal; a waveform memory that stores the output signal of the digitization circuit; an offset control circuit that outputs offset data to be given to the analog input signal; and an offset control circuit that converts the offset data output from the offset control circuit into an analog signal and transmits the signal to the amplifier. an output signal of the waveform memory and an output signal of the offset control circuit are added, and when the analog input signal is output from the changeover switch, the output signal of the waveform memory is sent out, and the output signal of the waveform memory is sent out, and the output signal of the waveform memory is a data switch that sends out the output signal of the offset control circuit in a state where the offset control circuit is output, and a display that selectively drives a plurality of display pixels arranged two-dimensionally in accordance with the output signal of the data switch. A digital waveform display device comprising: