JPH0277082A - Crt display system - Google Patents

Abstract

PURPOSE:To simplify a circuit by writing sweep data of a (y)-axial deflecting signal (saw-tooth wave) for character and symbol display in the memory for a character generator, and reading the data over D/A conversion. CONSTITUTION:The sweep data which are used basically to generate the (y)- axial deflecting signal (saw-tooth wave) for character display are written in the memory 4 for the character generator by using its free bits. The data and input waveform data which are written in the memory 2 are switched and converted by a D/A converter 3 into analog data, and an input waveform and a character are displayed on the same screen. Therefore, even when the 8-bit ROM for the character generator is used, a brightness signal is outputted as one-bit serial data, so the sweep data of the saw-tooth wave are written in remaining free bit to eliminate the need to provide a saw-tooth wave generating circuit separately. Consequently, the circuit constitution is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a CRT display system suitable for use in, for example, patient monitoring devices.

[Summary of the invention]

In the CRT display system, the present invention utilizes the empty focus in the character generator memory where only luminance signal data is normally written to create a y-axis deflection signal (sawtooth wave) for character display. By writing sweep data in advance and switching between this data and manual waveform data written in other memory to perform UlA* conversion, the input waveform and text information can be displayed on the same screen. .

[Conventional technology]

For example, a CR'l'' display in a patient monitoring device is designed to display measured values and other text information on the same screen in addition to displaying waveforms such as electrocardiogram waveforms.

The circuit configuration of a conventional C, R'1' display of this type will be explained with reference to FIG. 7. First, the waveform display is performed by digitally converting a waveform input signal by an AID converter (1) and writing it into a memory (2). This waveform data is sequentially read out in accordance with the X-axis (horizontal) sweep and converted into analog data by the D/A converter (3) to become the y-axis (vertical) fa number. ) creates a sawtooth wave sweep signal as a y-axis deflection signal, and outputs the character data written in the character taxi generator memory () as a brightness modulation signal, and both are sent from the timing circuit (6). The waveform display section and the character display section are alternately displayed to form a screen.

[Problem to be solved by the invention]

However, in this conventional example, a sawtooth wave generation circuit is provided to generate a sawtooth wave as a y-axis deflection signal, which complicates the circuit configuration accordingly, and the waveform shaping operation of this sawtooth wave is difficult. There are difficult issues. Further, since the y-axis sweep is performed even when no characters, symbols, etc. are displayed in the character display section, power is often wasted.

The present invention has been made in view of these points, and an object of the present invention is to solve the above-mentioned problems.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a CRT display system that uses a blank space in the character generator memo, in which only luminance signal data has conventionally been written. Use the bits to write the sweep data that follows the y-axis deflection signal (sawtooth wave) for character display, and switch between this data and the input waveform data written to the memory (2). Analog conversion is performed by the A converter (3), and the input waveform and characters are displayed on the same screen.

[Effect]

By writing the sawtooth wave sweep data into the empty bits of the character generator memory in this way, it is no longer necessary to provide a separate sawtooth wave generation circuit, which simplifies the circuit configuration. Ru.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to FIGS. 1 to 6.

FIG. 1 shows the basic configuration according to the method of the present invention, and parts corresponding to those in the conventional example shown in FIG. 7 described above are given the same reference numerals. In the character generator memory (4) that was
This is the data for the sawtooth wave.

That is, a ROM in which -1 luminance signal data is written in advance is normally used as a character taxi generator, but even if a general-purpose 8-pin ROM is used, the luminance signal is output as 1-bit serial data, so the remaining 7 Bits are often wasted without being used. Therefore, in the present invention, the remaining bits are used to write in advance the y-axis deflection signal for characters, symbols, etc. to be displayed, that is, the sweep data that is the source of the sawtooth wave, and this data and the waveform input signal. The waveform data written in memory (2)
It is continuously switched by a control signal from a timing circuit (6), and analog conversion is performed by a D/A converter (3) to create a sawtooth wave, thereby simplifying the circuit.

For example, a 3276B word x 8 bit ROM is used as the character generator memory (each memory), and of the address (AO"A14), the lower 8 bits (Ao"
=At) is the address count clock from the timing circuit, the next 6 bits (As-A13) are the character selection code, and the most significant bit (A14) is the address count clock from the timing circuit.
) is assigned a bit that switches the screen display position between the top and bottom ends, as will be described later.

FIG. 2 shows a specific example of the configuration of the main parts according to the method of the present invention.

In the figure, (7) is a ROM as a character generator in which brightness signal data for future characters and sweep data for sawtooth waves are written. At the same time, character data is sent through the counter (11), and an address count clock is sent from the counter (11), whereby predetermined brightness signal data is output as a brightness modulation signal and sawtooth wave data is read out.

Further, digitally processed input waveform data is output from the CPU f81 and is temporarily stored in the buffer (12), and this waveform data and the sawtooth wave data read out from the ROM (7) are The signals are alternately switched by a counter (11) and sent to a D/A converter (13), converted into analog signals, and output as a y-axis signal to a subsequent deflection circuit.

Figure 9A3 shows an example of a CRT display according to the method of the present invention.

In this example, a waveform is displayed in the center of the screen, and a plurality of characters are distributed and displayed at the top and bottom of the screen. This character has 2 characters in the y-axis direction and 15 characters in the x-axis direction.
Although a maximum of 30 characters can be displayed, the drawing shows an example in which only a portion of them are displayed.

Furthermore, as shown in Fig. 4, the - character is composed of a maximum of 8 x 8 dots, and in this example, out of these 8 x 8 dots, 5 x 7 dots are used to write "3" in the upper row and "5" in the lower row. ” is displayed.

Figure 5 shows the overall timing; in this case, the frame time required to construct one CRT screen is, for example, 1
The first half of the period is 6.384 msec, and the first half is a character section, which is divided into 16, which is 512 μsec, to display the upper and lower two characters of one column out of 15 columns (characters) in the X-axis direction. Furthermore, this 512 μsec is divided into 8, which is 64 μsec.
Then, the Y-axis sweep is performed by one dot among the eight dots in the X-axis direction of one character, that is, the sweep is performed by one vertical line of the sawtooth wave.

Then, 32 μsec, which is a portion of this 64 μsec, becomes the display section, 32 μsec becomes the flyback section, and 32/jsec
16μsec of the display section is upper row characters, 16μsec
c is assigned to display the lower character. Since one character has 8 dots in the y-axis direction, the sweep time for one dot is 2μ.
sec.

FIG. 6 shows the appearance of one vertical sawtooth wave in this character sweep.

As is clear from the figure, since sweep data can be obtained every 2 μsec for 1 dot, and the shape of the sweep waveform can be created arbitrarily, it is also possible to correct the distortion of the deflection circuit in the subsequent stage in order to achieve linearity in character display. It's easy to do.

Also, ROM as memory for character generator
By separately writing data consisting of the sawtooth wave in Figure 6 plus an offset in the y-axis direction to the address that can be switched by switching the most significant bit of It can be displayed separately at the lower end and at the lower end.

〔Effect of the invention〕

As described above, the present invention writes the sweep data of the y-axis deflection signal (sawtooth wave) for character/symbol display into the character generator memory, and extracts it by D/A conversion. Since the waveform of the sawtooth wave can be set arbitrarily, it is possible to correct distortion in the subsequent deflection circuit, and also to
Since the waveform of the sawtooth wave can be set for each symbol, sweeping of the y-axis can be stopped in the blank portion, reducing unnecessary power loss. In addition, since the remaining bits of memory are used, timing can be easily determined and the circuit can be simplified.Furthermore, since the y-axis signal is extracted using digital data,
It has various effects such as no variation in characteristics.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration according to the present invention, FIG. 2 is a configuration diagram of a specific embodiment, FIG. 3 is a diagram showing an example of display according to the method of the present invention, and FIG. FIG. 5 is an explanatory diagram of CRT display timing, FIG. 6 is a diagram showing a sawtooth waveform for character display, and FIG. 7 is a block diagram showing a conventional example. In the figure, (2) is input waveform memory, (3) is D/A converter, (4) is character generator memory, (6)
is a timing circuit.

Claims (1)

[Claims] In a CRT display system that displays input waveforms and character information on the same screen, in a character generator memory in which luminance signal data is written, a y-axis deflection signal for character display is stored. Write sweep data in advance, and switch between this data and input waveform data written in other memories to
A CRT display system in which the screen is constructed using A conversion.