JPS58168087A - Raster scanning crt analog waveform display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for displaying analog waveforms using an XY matrix display method (a method for displaying a CRT surface as vertical raster lines x horizontal dots).

Conventionally, when displaying analog waveforms on a CRT (cathode ray tube) as a memory scope, the following two methods have been used.

(b) A direct method in which an electron beam is deflected electrostatically or electromagnetically using signals that are directly time-converted in the horizontal and vertical directions.

(b) Assuming a raster for the CRT, divide the horizontal and vertical directions into pixels, and store f in the memory corresponding to each pixel.
An X-Y matrix method that writes OJ and rlJ and displays the analog waveform as the sum of them.

In method (a), since a deflection signal is directly applied, the movement of the electron beam can be displayed continuously by using an appropriate smoothing means, and because the displayed waveform looks smooth, it is used in many analog waveform display devices (e.g., electrocardiogram waveforms). , blood pressure waveforms, etc.) are used for each Yuzu memory scope).

Method (B) is often displayed together with text, graphs, etc., but if analog waveforms can be displayed with the same level of image quality as method (B), then method (B)
It has the following advantages compared to the above method.

■ Low power consumption.

■ Large CRT can be used.

■ Multi-color CRTs such as R, G, and B can be used.

■ Characters and graphs can be displayed simultaneously.

However, when displaying analog waveforms using the method (b),
033 and Japanese Patent Application Laid-Open No. 159270/1984, all of them have conventionally attempted to display 1IiIi elements as one dot, but when there is data to be displayed at the boundary between a pixel and an llll1i element, has an interval as shown below.

FIG. 1 is an explanatory diagram showing this relationship. In the figure,
White circles indicate the positions of displayed dots, black circles indicate the positions of dots to be removed, and triangular marks indicate the positions of dots interpolated as described below. Now, assuming that the resolution in the horizontal (X) direction is H, the effective length of the CRT in the X direction is H, and the number of pixels in the X direction is N, the following equation holds true.

k=H/N (simple/DOT) On the other hand, regarding the time relationship, the horizontal scanning period is b.

Let f be the 4-line period and a be the readout time of the l dot, then
The following formula holds true.

−f a −N (S) Therefore, if the 1jIS number N is increased in order to reduce the resolution k, a will be decreased. That is, the readout time per dot becomes shorter. If we want to keep 1 constant and k to a satisfactory value, h−f must be increased. Here, the repetition period of one screen is F, and the number of raster lines is L.
Then, since F=(h-f)·L, when h-f is large, F also becomes large, and this appears as 7 ritsuka on the - plane.

From the above relationship, it can be seen that in order to improve the resolution k, N must be increased and the inevitable llCa must be decreased. However, in order to reduce a, there is a limit to the data output speed of the memory corresponding to the pixel, (
2) There are constraints such as an increase in the number of memories used in h-f, and it is difficult to achieve a predetermined purpose by a simple method and at low cost.

Next, a method for interpolating the discontinuities between the dots shown in FIG. 1 will be described. For example, in 4I Publication No. 54-152822, as shown in FIGS. 2 and 3, interpolation for discontinuous waves is performed using dots as units. In this method, the interpolation dot is placed at the position of the triangular mark, so in the case of Fig. 2, it is not so far, but in the case of Fig. 3, the actual position to be displayed is the black circle mark. I have no choice but to end up with an unnatural display. This is because there is a limit to the resolution in the horizontal direction, and the only way to solve this problem is to improve the resolution to 5 above.

However, method (b) has the following disadvantages compared to method (b). That is, the amplitude and position of the analog display waveform can be easily adjusted by directly adjusting the waveform to be deflected using the direct deflection method, but the X-Y
To adjust the amplitude and position of the matrix method, use ■Input A/
It is necessary to take measures such as changing the data before inputting it into the D conversion device, and storing it once in the auxiliary memory, and then storing it in the display matrix memory (video RAM) after taking into account the number of display S, etc. when displaying. In the case of (2), when expanding or narrowing the transient signal, it is necessary to input it again from the A/D converter, and these requirements cannot be met.

In the case of (2), an auxiliary memory is required in addition to the matrix memory for display, and since processing is performed using coefficients, the configuration is coarse and monovalent.

Furthermore, in method (b), when displaying a color CRTK &
In order to color every 1jIll element, a memory for coloring every 1kI element is required. For example, if there are 8 color ridges to express, 3 bits are required, so all -
In order to display the direction, the memory required is several times as many as m.

It should be noted that the following two methods have conventionally been used to determine whether it is necessary to perform analog display and display new data sequentially on the screen at 5WA.

(1) A display method in which waveforms are continuously recorded on recording paper.

(-) A display method that moves discontinuous points on the screen by sweeping it like a monitor oscilloscope.

Method (11) is easy, as it is sufficient to sequentially replace the corresponding dots with new data when rewriting the screen.

However, method (1) requires the entire screen to be rewritten, so it requires additional measures such as using equivalent X-Y memory and displaying it alternately, which is complicated and not easy. .

The present invention aims to provide a two-star scanning CRT analog waveform display device that completely eliminates the above-mentioned problems. A feature of the present invention is that by using a novel pulsing circuit, an analog signal waveform can be displayed as a smooth shape on a raster scan CRT* display. Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 4 is a block diagram 111 showing an embodiment of the present invention. -, (1) is an analog signal input terminal, (
2) is an analog-to-digital converter, (3) is a write control circuit, (4) is a waveform memory, (5) is an indulgence control circuit, and (6) is a digital-to-analog converter. As shown in the box, it is the same as the conventional direct method.

In the figure, only one channel is shown for simplicity. The analog signal read from the waveform memory (4) within the horizontal period is smoothed by a smoothing circuit (7) using a low-pass filter.
The voltage is applied to the video pulsing circuit (8). The video pulsing circuit (8) converts an analog signal into a video pulse unique to the present invention as described later, and its output is C) LT (9
Supply to 1. Ql is the clock pulse generator t11
This is a sampling pulse generation circuit that generates a sampling pulse from the output of ) to control the A/D converter t2) and the write control 41 circuit (3). Q4 and a are circuits that generate horizontal synchronization pulses and vertical synchronization pulses, respectively, from the output of the clock pulse generator Uυ.

FIG. 5 is a waveform for explaining the operation of FIG. 4.

FIG. 5A shows an analog signal waveform applied to the input terminal (1), for example, one second of which is stored in the waveform memory (4). FIG. 5B shows the output waveform of the D/A converter (6), which is the waveform of FIG. 5A read out at time (h-f). FIG. 5C shows a smoothed waveform (reproduced waveform) of FIG. 5B.

Figure 1m6 is a block diagram showing an example of the Eirin pulse generation circuit (8) used in the present invention. 7 to 9 are waveform diagrams for explaining the operation. ■~ in Figure 6 is the 7th
- Shows the locations where the ai waveforms in FIG. 9 appear. In FIG. 6, the smoothed output waveform of FIG. 5C is applied to the input terminal Q4). This input waveform is compared with different reference signal waveforms in the first comparator aS and the second comparator (lfj). One of the reference signal waveforms is a staircase wave as shown in i in FIG. The counter counter counts each horizontal synchronization pulse applied to the count terminal C.
Reset terminal RK is reset every time a vertical synchronization pulse is applied. , the number of steps of this staircase wave is determined corresponding to the raster edge of the screen, so the level of each step (O9l).

2,...) will be called the raster level. In other words, the level of the reference signal wave engraving supplied to the first comparator a4 is horizontally synchronized and sequentially changes by l steps. The other side of the reference signal waveform is level shifter Q? ), for example, by one step (FIG. 9g) and supplied to the second comparator Q-. O8
It is also level chic, but I will discuss this later. Here, the number of levels to be shifted may determine the thickness of the edge of the displayed waveform, or may not necessarily be l steps.

Assume that the input waveform is a triangular wave, and the chic waveform shown in Figure 9 is
Comparing it with the level, 1. The result will be as shown in Figure 7A.

When the reference raster level input to the first comparator field a is 0, the peak of the triangular wave does not reach this level, so the output of the first comparator α1 is 0 (a in Figure 7B). ). On the other hand, in the M2 comparator (2), if the number of steps in the level shifter is 1, the thick level is 1, so the width is short (pulse is generated (b in FIG. 7B)). This b pulse is generated by the exclusive OR circuit Qυ, (2) and the delay circuit (c).
added to.

,,,,,,1:,:.

Here, the delay circuit is a circuit that provides a constant delay time τ to a pulse having a constant pulse width or more.

Since the b pulse does not reach its constant pulse width, the delay circuit (2) produces no output (FIG. 7Bf)d). Therefore, the exclusive OR circuits Qυ and O4 output the same pulse as the b pulse (c, e in FIG. 7B). Yotsu°(,CR
T (91) The output of the OR circuit (2) that modulates the brightness of the electron beam also becomes as shown in f in Figure 7B, and a corresponding bright spot appears on the screen of the CRT (9) (r- in Figure O7). (bright spot on top). Fig. 7 D Niol*O', 1', 2'.

3'...... is sick level 0, 1,
2,3. Indicates the thick line corresponding to .

Next, the sick level input to the first comparator Q9 is 1.
Then, the first comparator Q generates the same pulse as the b pulse in FIG. 7B (FIG. 7C, a). At this time, the sick level to the second comparator 1e is 2, so the
This produces the pulse shown in b.

Therefore, the output of υ, which is an exclusive OR circuit, becomes the pulse shown in C in Figure C of wX7. The output of the second comparator ae is output from the exclusive OR circuit c! along with the pulse shown at d in FIG. 7C, which is delayed for 7 hours by the delay circuit (c). The C pulse and C pulse in Figure 7 C pass through 4 which is an OR circuit, and the pulse shown in C in Figure 7-0 is generated at its output.
The pulse is shown as f. This f pulse becomes a bright line on the CRT screen as shown on the 2' line in Figure 7.
Similarly, the triangular waveform as shown in Figure 7 is CR
Displayed on TIfo.

In reality, the thickness of the line indicating the waveform will be thinner than in the diagram.

When the input waveform is a square wave, it becomes as shown in FIG.

In this case, as shown in Figure 8C, exclusive OR times w6
Although the output of ea becomes 0, it is corrected as shown in Figure 8 by the second comparator ae, the delay circuit (c), and the exclusive OR circuit (c). In this case, it should be noted that the waveform in the thick direction is displayed continuously as shown on the r line in the same figure.

Furthermore, as a means to improve the resolution in the vertical direction, an interlacing method is usually adopted, and even in this case, the D/A converter (61) is used as described above.

Since the analog sakagata mater which has passed through the smooth rotation % (7) is continuous also in the vertical direction, this method can be easily applied.
A small voltage corresponding to the thick level to be interlaced is added to the reference staircase wave generation circuit for every other synchronization signal (in Figure 6, the D/A converter reference (added to the signal), it is possible to obtain interlaced thick video pulses.

Although the above explanation was made regarding the case where the reference signal waveform is level-shifted, the input waveform may also be level-shifted. In this case, the level shifter Ql is connected as shown in FIG. However, one more amplifier is required.

Further, if it is desired to display waveforms in multiple channels such as R, G, and B using a color CRT, the configuration is easy because the video signal is already pulsed as described above. In this case, the priority order when waveforms are displayed simultaneously at the same position can be easily determined because the pulses are generated for each channel. For example, using an inverter, channel L (red) and channel 2 (green)
The priority may be channel 3 (blue).

As is clear from the above explanation, according to the present invention, the following remarkable effects can be obtained.

(a) Since the displayed analog waveform is continuous, unlike a dot matrix, the resolution in the horizontal direction is improved.

(b) Since the waveform is smoothed, it becomes continuous and no special interpolation is required.

(C) Amplitude and position of displayed analog waveform ll11
A one-way system is simple and requires only an analog circuit.

(d) Since the video pulse waveform is output for each channel, multi-color display can be performed with mJ performance with a simple configuration.

(e) The overall circuit configuration is simpler and cheaper.

(f) The waveform display mode can be made equivalent to the conventional memory scope.

It should be noted that the present invention is not limited to the above-described embodiments, and may be modified and modified in various ways without departing from the gist of the invention as set forth in the claims.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams showing a conventional example, Fig. 84 is a block diagram showing an embodiment of the present invention, Fig. 5 is a waveform diagram for explaining the operation of Fig. 4, and Fig. 6 is an image used in the present invention. Pulsing circuit 1
A block diagram showing an example, and FIGS. 7 to 9 are waveform diagrams for explaining the operation. (4)...Digital memory, (5)...
...Reading control circuit, (6)...Digital...
Analog converter, (7)...Smoothing circuit, Ql,
cA...Reference staircase wave generation means, aη, (I8・
...Level chic, (c)...First comparison means, cod...Second comparison means, Nari...
・First exclusive OR circuit ゛, ■...Second exclusive OR circuit, (2)...Delay circuit, C24)・Tap・
OR circuit, (9)...CRT0

Claims (1)

[Claims] 1. Digital-to-analog conversion means for converting a signal read from a digital memory into an analog signal, means for generating a reference staircase wave whose level changes sequentially in raster synchronization, and this reference means for shifting the level of the staircase wave by one step or an integral multiple thereof; first comparison means for comparing the analog signal with the reference staircase wave; and first comparing means for comparing the analog signal and the shifted reference staircase wave. a first exclusive OR circuit whose inputs are the outputs of the first and second comparison means; and a first exclusive OR circuit whose inputs are the output of the second comparison means and the delayed output of the second comparison means. 2 exclusive OR circuits, and the above first and second! #A rask scanning CRT analog waveform device comprising an OR circuit which receives the output of another OR circuit as an input, and means for changing the electron beam of a CRT which is raster scanned by the output of the OR circuit by 11 degrees. 2. Digital-to-analog conversion means for converting the signal read from the digital memory into an analog signal, means for generating a reference staircase wave whose level changes sequentially in raster synchronization, and converting the level of the analog signal into the reference. means for shifting the staircase wave by one step or an integer multiple thereof; first comparing means for comparing the analog signal with the reference staircase wave; and comparing the level-shifted analog signal with the reference staircase wave. a second comparison means, and the first and second comparison means;
a first exclusive OR circuit whose input is the output of the comparison means; a second exclusive OR circuit whose input is the output of the second comparison means and the delayed output of the second comparison means; A rask scan CRT analog waveform display device comprising: an OR circuit which receives the output of a second exclusive OR circuit; and means for modulating the brightness of an electron beam of a CRT subjected to raster scanning based on the output of the OR circuit.