JPS5920106B2 - cathode ray tube signal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube signal display device, and more particularly to an improvement in a cathode ray tube signal display device that performs brightness modulation to display a broken signal waveform on a cathode ray tube.

By forming a pulse position modulation signal modulated according to the amplitude of the observed input signal and using this signal to modulate the brightness of the cathode ray tube, the human input signal is displayed as a continuous bright spot on the screen of the cathode ray tube. However, a device that allows an observer to perceive the light as a continuous bright line is known. FIG. 1 is a block diagram showing a device for performing brightness modulation and displaying a broken line signal waveform on a cathode ray tube. The level comparison circuit 1 compares the signals, and a pulse width modulated signal shown in FIG. 3C is formed as an output of the comparison circuit 1.

This pulse width modulated signal C is further applied to a pulse rising edge detection circuit 2, and a pulse position modulated signal as shown in FIG. 3B is formed as an output of this detection circuit 2. This signal 2 is further amplified by the video amplification circuit 8 and supplied to the cathode electrode of the cathode ray tube 15. Further, the Y-axis deflection coil 12 of the cathode ray tube 15 is supplied with the output of the sawtooth wave generator 9 via the Y-axis deflection amplifier 11, and the X-axis deflection coil 14 is supplied with the sawtooth wave generator 9 via the X-axis deflection amplifier 13. Generator 10
output is supplied. In this way, a brightness modulation signal with a predetermined pulse width is applied to the cathode electrode of the cathode ray tube 15 every time the sawtooth generator 9 generates a sweep signal.
As shown in FIG. 4, the input signal is displayed on the tube surface of 5 as a continuous bright spot, which is perceived by the observer as a single bright line. However, in these conventional technologies, since the sweep frequency is constant, as the amplitude of the input signal increases and the frequency of the input signal increases, the interval between the bright spots displayed on the cathode ray tube becomes wider, and the bright spots are recognized as broken lines. It becomes difficult to see.

The present invention aims to eliminate these drawbacks of the prior art, and its first object is to display a brightness modulation type cathode ray tube display that provides an easily observable display even when the amplitude and frequency of the input signal changes. The second objective is to form a signal by differentiating the input signal, and use this differentiated signal to control the circuit of the display device, so that it can be observed in parts where the input signal changes rapidly. The purpose is to obtain a cathode ray tube display device that prevents the waveform from becoming difficult to see.The third objective is to form a bright line that connects the bright spots in the conventional brightness modulation method, and to use this to form a bright line that connects the bright spots to the input signal. The object of the present invention is to obtain a cathode ray tube display device with an easy-to-see waveform that is faithful to the input signal by drawing the waveform on the tube surface.

The features, objects, and advantages of the present invention will become more apparent from the detailed description of FIG. 2, which schematically illustrates the invention, and FIGS. 3 and 5, which illustrate the invention.

First, the input signal shown in FIG.

The output of the sawtooth generator 9 is supplied to the other terminal of the level comparison circuit 1, and a pulse width modulated signal as shown in FIG. 3C is obtained as the output of the level comparison circuit 1. The leading edge of this signal C is detected by the pulse rising edge detection circuit 2, and the sawtooth wave generator 5 is triggered using the pulse rising edge detection circuit 2. On the other hand, the input signal E differentiated by the differentiating circuit 3 is input to the full-wave rectifier circuit 41fC. After being subjected to full-wave rectification A, it is applied to a level comparison circuit 6 together with the output of the sawtooth wave generator 5. Here, the level comparison circuit 6 compares the output waveform of the sawtooth wave generator 5 with the full-wave rectified waveform, and when the value exceeds a certain value, outputs the waveform shown in FIG. When the waveform 1 is amplified by the video amplifying circuit 8 and supplied to the cathode electrode of the cathode ray tube 15, a waveform consisting of continuous short line segments (dots divided into lines) as shown in FIG. 5 is obtained. Note that if brightness modulation is performed using only the output signal of the level comparison circuit 6 which is substantially pulse width modulated according to the input waveform, the width of the bright line may become extremely short depending on the input signal.
The output of the pulse rising edge detection circuit 2 is applied to the video amplifier circuit 8 via the OR circuit 7, so that good waveform observation can always be performed. As described above, the present invention differentiates the input signal and compares the level of the full-wave rectified waveform and the sawtooth signal triggered by the pulse position modulated signal of the input signal in order to find out its magnitude. Since the line segments of the obtained emission line length are displayed in a continuous form, observation can be performed with clear display without being affected by the amplitude and frequency of the input signal.

In addition, since the generation of the luminance signal is linked to the pulse position modulated signal, the shape of the display signal formed at least at the starting point of the luminance line is similar to the shape of the input signal, and therefore, the shape of the display signal formed at least at the starting point of the luminance line is similar to the shape of the input signal. A bright line shape that connects points can be obtained, and an easy-to-read display that is faithful to the input signal can be obtained.

[Brief explanation of the drawing]

The drawings all show examples, and Fig. 1 is a block diagram of a conventional circuit, Fig. 2 is a block diagram of a circuit of the present invention, Fig. 3 is a waveform diagram of each part, and Fig. 4 is a block diagram of a conventional circuit. FIG. 5 is a display waveform diagram according to the conventional circuit, and FIG. 5 is a display waveform diagram according to the present invention. Here, 1...Level comparison circuit, 2...Pulse rising detection circuit, 3...Differentiating circuit, 4...Full wave rectifier circuit, 5...Sawtooth wave generator, 6...Level Comparison circuit, 7.
...OR circuit, 8...Video amplification circuit, 9,10...
- Sawtooth generator, 11...Y-axis deflection amplifier, 12...
Y-axis deflection coil, 13...X-axis deflection amplifier, 14...
-X-axis deflection coil, 15...Cathode ray tube.

Claims (1)

[Scope of Claims] 1. Pulse position modulation means that compares the input signal level with a display bright spot scanning signal and converts it into a pulse position modulated signal, a differentiation circuit that outputs a differential signal of the input signal, and A pulse width modulation means is provided for generating a signal modulated with a pulse width corresponding to the magnitude of the differential signal in conjunction with the position modulated signal, and the output of the pulse width modulation means is used as a luminance signal to the cathode ray tube. Cathode ray tube signal display device as input. 2. A pulse position modulation means that compares the input signal level with the bright spot scanning signal of the display and converts it into a pulse position modulated signal, a differentiation circuit that outputs a differential signal of the input signal, and a differential circuit that outputs a differential signal of the input signal, and a A pulse width modulation means is provided which generates a signal modulated to a pulse width corresponding to the magnitude of the differential signal in conjunction with each other, and the output of the pulse width modulation means and the output of the pulse position modulation means are used as a luminance signal input. Cathode ray tube signal display device.