JPH0329570A - Dynamic speed modulation circuit - Google Patents

Abstract

PURPOSE:To sufficiently obtain the effect of speed modulation even at a surrounding part of a pattern with inferior focusing by increasing the amplitude of a quadratic differentiating waveform of a composite video signal at the surrounding of the pattern more than that in the middle. CONSTITUTION:An inputted composite video signal is subject to amplification processing by a video circuit 3 and a quadratic differentiating circuit 4 obtains a quadratic differentiating output of the composite video signal and a synchronizing separator circuit 7 separates a vertical synchronizing signal and a horizontal synchronizing signal from the composite video signal. A vertical synchronization parabolic wave generating circuit 8 generates a vertical synchronization parabolic wave from the vertical synchronizing signal. Then a vertical synchronization parabolic wave generating circuit 9 generates a horizontal synchronization parabolic wave from the horizontal synchronizing signal and a 1st multiplier 10 multiplies the vertical synchronization parabolic wave with the horizontal synchronization parabolic wave. Then a 2nd multiplier 11 the output of the quadratic differentiating circuit 4 with the output of the 1st multiplier to increase the amplitude of the quadratic differentiating signal at the surrounding of the pattern. Thus, the effect of the speed modulation is obtained even at the surrounding part of the pattern.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a dynamic speed modulation circuit for a television receiver, for example, a dynamic speed modulation circuit for a television receiver that uses a composite video signal such as the NTSC system as an input signal. It is related to circuits.

[Prior Art] Fig. 3 is a block diagram showing the configuration of a speed modulation circuit of a conventional television receiver, and the speed modulation circuit (1a) has a manual terminal (2) for inputting a composite video signal. A video circuit (3) for processing a composite video signal and a second-order differential circuit (4) for obtaining a second-order differential output of the composite video signal are connected to the human input terminal (2).

And on the output side of the video circuit (3) is a cathode ray tube (5).
A velocity modulation coil (hereinafter referred to as SVM coil) (6) of a cathode ray tube (5) is connected to the output side of the second-order differential circuit (4).

Next, the operation will be explained.

When a composite video signal (1 0 0) having a waveform as shown in FIG. 4(a) is input from the input terminal (2) to the video circuit (3) and the second order differential circuit (4), the video circuit (
Although the output waveform of step 3) does not change, the output waveform of the second-order differentiator circuit (4) becomes as shown in FIG. 4(b).

Then, the output of the video circuit (3) is input to the cathode ray tube (5), and the output of the second order differential circuit (4) (see FIG. 4(b)) is input to the SvM coil (6).

At this time, the scanning speed of the beam is as shown in Fig. 4(C), and the brightness displayed on the cathode ray tube (5) is as shown in Fig. 4(d).
This results in speed modulation with emphasized contours.

[Problems to be Solved by the Invention] By the way, in conventional television receivers, the focus is poor at the periphery of the screen. For example, as shown in FIG. , E points have poor focus, and F, (;, H, 1 point has a problem that focus is even worse.

For this reason, in the speed modulation circuit of conventional television receivers, the scanning speed of the beam is determined only by the second derivative of the video signal, so the problem is that the speed modulation effect cannot be sufficiently achieved in the peripheral areas of the screen where focus is poor. was there.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a dynamic speed modulation circuit that can obtain speed modulation effects even in the peripheral areas of the screen.

[Means for Solving the Problems] A dynamic speed modulation circuit according to the present invention includes: a video circuit that amplifies a composite video signal; a second-order differential circuit that obtains a second-order differential output of the composite video signal;
A sync separation circuit that separates a vertical sync signal and a horizontal sync signal from a composite video signal, a vertical sync parabolic wave generation circuit that generates a vertical sync parabolic wave from the vertical sync signal, and a horizontal sync circuit that generates a horizontal sync parabolic wave from the horizontal sync signal. A synchronous parabolic wave generation circuit, a first multiplier that multiplies a vertical synchronous parabolic wave and a horizontal synchronous parabolic wave, and a second multiplier that multiplies an output of a second order differential circuit and an output of the first multiplier. It is prepared.

[Effect]

The dynamic speed modulation circuit of the present invention amplifies and processes a human-powered composite video signal using a video circuit, obtains a second-order differential output of the composite video signal using a second-order differentiator, and converts a vertical synchronization signal from the composite video signal using a synchronization separation circuit. and a horizontal synchronization signal, a vertical synchronization parabola wave generation circuit generates a vertical synchronization parabola wave from the vertical synchronization signal, a horizontal synchronization parabola wave generation circuit generates a horizontal synchronization parabola wave from the horizontal synchronization signal,
The first multiplier multiplies the vertically synchronized parabolic wave and the horizontally synchronized parabolic wave, and the second multiplier multiplies the second-order differential circuit output and the first multiplier output. Increase the amplitude of the differential signal.

[Length example] An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the speed modulation circuit (1) has a manual terminal (2) for manually inputting a composite video signal, and the input terminal (2) has a video circuit (3) for processing the composite video signal, a composite A second-order differentiation circuit (4) that obtains a second-order differential output of the video signal and a synchronization separation circuit (7) that separates a vertical synchronization signal and a horizontal synchronization signal from the composite video signal are connected.

A cathode ray tube (5) for displaying images is connected to the output side of the video circuit (3), and a synchronization separation circuit (7)
A vertically synchronized parabolic wave generating circuit (8) for generating a vertically synchronized parabolic wave from a vertically synchronized signal is connected to the output side of the circuit, and a horizontally synchronized parabolic wave generating circuit (9) for generating a horizontally synchronized parabolic wave from a horizontally synchronized signal is connected. The output side of the vertical synchronous parabolic wave generation circuit (8) and the horizontal synchronous parabolic wave generation circuit (9) are connected to the output of the vertical synchronous parabolic wave generation circuit (8) and the horizontal synchronous parabolic wave generation circuit (9).
A first multiplier (10) for multiplying the output by the output of the first multiplier (10) is connected.

Further, the output side of the first multiplier (10) and the output side of the second-order differentiator circuit (4) are multiplied by the output of the first multiplier (10) and the output of the second-order differentiator circuit (4). Second multiplier (11
) is connected, and the SVM coil (6) of the cathode ray tube (5) is connected to the output side of the second multiplier (l1).

Next, the operation of this embodiment will be explained.

From the human power terminal (2) to the video circuit (3) and the second-order differential circuit (4)
) and the synchronization separation circuit (7), when a composite video signal (1 0 0) with a waveform as shown in Fig. 2(d) is input manually, the output waveform of the video circuit (3) does not change and the secondary The output waveform of the differentiating circuit (4) is as shown in FIG.
0) to separate the vertical synchronization signal and horizontal synchronization signal.

The vertical synchronization signal separated by the synchronization separation circuit (7) is then manually inputted to the vertical synchronization parabolic wave generation circuit (8).
The horizontal synchronization signal is manually input to a horizontal synchronization parabolic wave generation circuit (9).

Then, the vertical synchronous parabolic wave generation circuit (8) which manually inputs the vertical synchronous signal generates a vertical synchronous parabolic wave (see Figure 2 (b)), and the horizontal synchronous parabolic wave generator circuit (9) which manually inputs the horizontal synchronous signal. is a horizontally synchronous parabolic wave (Fig. 2 (a)
)) occurs. In addition, V in the figure is vertical synchronization, H is horizontal synchronization, and in the case of NTSC system, V-60Hz, H
-15kHz.

Further, the vertical synchronous parabolic wave generated by the vertical synchronous parabolic wave generation circuit (8) and the horizontal synchronous parabolic wave generated by the horizontal synchronous parabolic wave generation circuit (9) are input to the first multiplier (10). The signals are multiplied and a waveform as shown in FIG. 2(C) is obtained.

Then, the output of the multiplier (10) of TS1 (Fig. 2(c)
) and the output of the second-order differential circuit (4) (see Fig. 4(b)) are manually multiplied by the second multiplier (11), and the output of the second multiplier (11) is multiplied by the SVM. It is input to the coil (6).

At this time, if the video signal has a waveform as shown in FIG. figure(
It is represented by a waveform like e), and it is possible to perform velocity modulation with a large amplitude in the peripheral area of the screen.

[Effects of the Invention] As explained above, according to the present invention, the amplitude of the second-order differential waveform of a composite video signal is larger at the periphery than at the center of the screen. The effect of speed modulation can be sufficiently obtained even in the peripheral area of the vehicle.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a dynamic speed varying 2J circuit according to an embodiment of the present invention, FIG. 2 is a diagram showing waveforms at various parts of the speed modulation circuit, and FIG. 3 is a diagram showing the configuration of a conventional speed modulation circuit. FIG. 4 is a diagram showing waveforms at various parts of a conventional speed modulation circuit, and FIG. 5 is a diagram for explaining focus of a receiver. In the figure, (1) and (1a) are speed modulation circuits, (3)
is a video circuit, (4) is a second-order differential circuit, (7) is a synchronous separation circuit, (8) is a vertical synchronous parabolic wave generation circuit, (9) is a horizontal synchronous parabolic wave generation circuit, (10) is a first (11) is the second multiplier. In addition, the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] In a dynamic speed modulation circuit that inputs a composite video signal, there is a video circuit that amplifies the composite video signal, a second-order differential circuit that obtains a second-order differential output of the composite video signal, and a vertical synchronization signal and a horizontal synchronization signal from the composite video signal. A synchronous separation circuit that separates the vertical synchronous parabolic waves, a vertical synchronous parabolic wave generation circuit that generates a vertical synchronous parabolic wave from a vertical synchronous signal, a horizontal synchronous parabolic wave generation circuit that generates a horizontal synchronous parabolic wave from a horizontal synchronous signal, and a vertical synchronous parabolic wave generation circuit that generates a horizontal synchronous parabolic wave from a horizontal synchronous signal. A dynamic speed modulation circuit comprising: a first multiplier for multiplying by a horizontal synchronous parabolic wave; and a second multiplier for multiplying a second-order differentiation circuit output by a first multiplier output. .