JPS6034870B2 - special effects waveform generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a special effects waveform generator used in television special effects.

Traditionally, special effect waveform generators used for special effects called wipes, which divide the screen or change the screen using various shapes such as diamonds or circles, include sawtooth waves, triangular waves, parabolic waves, etc. By mixing the horizontal and vertical special effect fundamental waves and comparing them with the level of the fader control signal, the size of the figure was changed and the screen was changed using that figure.

That is, as shown in FIG. 1, a horizontal fundamental wave generating circuit 1 generates a horizontal fundamental wave such as a mirror tooth wave, a triangular wave, a parabolic wave, etc. at the timing of a horizontal synchronizing signal, and a vertical fundamental wave generating circuit 2 generates horizontal fundamental waves such as a mirror tooth wave, a triangular wave, and a parabolic wave.
generates a sawtooth wave, a triangular wave, and a parabolic vertical fundamental wave at the timing of the vertical synchronization signal, mixes the horizontal and vertical fundamental waves in the mixer circuit 3, and mixes the combined fundamental wave and the input terminal 5 in the comparator circuit 4. By comparing the level of the fader control signal and slicing the mixed fundamental wave at the level of the fader control signal, special effect fundamental waves of various shapes are generated and outputted from the output terminal 6.

For example, if the horizontal and vertical fundamental waves are chosen to be parabolic waves as shown in FIG. 2A, a circular shaped special effect waveform as shown in FIG. 2B is generated. By controlling the waveform slicing bell in FIG. 2, that is, the level of the fader control signal at the input terminal 5, from the minimum potential to the maximum potential of the mixed fundamental waveform, the size of the figure is changed from zero to the screen cropped state. In addition, if the slice circuit in the comparison circuit 4 is replaced with a soft slice circuit that clips the portions above point b and below point c of the waveform in FIG. 2 and amplifies and extracts the portion between b and c, the front green of the waveform as shown in FIG. , it is possible to generate a so-called soft line figure (green blur figure) with a wide rising width at the trailing edge, and by controlling the soft slice level with a fader control signal, the size of the figure can be changed in the state of a soft edge figure. I can do it. Furthermore, by adding a circuit configuration for extracting the green pulse as shown in FIG. 2D from the rising portion of the soft waveform as shown in FIG. Such special effect waveform generators have the disadvantage that the signal-to-noise ratio (S/N) of the graphic deteriorates due to external noise such as power supply hum that enters the mixing circuit, etc., or thermal noise generated from within the circuit. In particular, parabolic waves used for circular shapes, etc., have a slope near the top of the waveform that is nearly horizontal, as shown in the waveform A in Figure 2, so they are susceptible to the influence of noise such as power supply hum, etc. When the shape is narrowed down, the original shape of a circle is generated. The S/N had deteriorated to the point where it could not be stopped.

Also, when adding a soft green or borderline edge to a shape using a parabolic waveform, such as a circle, as the slice level reaches near the top of the waveform, the slope of the waveform becomes gentler and the width of the soft green or borderline edge becomes wider. It had drawbacks. In addition, when the parabolic waveform is sliced at the level of the fader control signal, the slope of the parabolic waveform is not a straight line but a square curve, so changes in the size of the figure do not correspond rationally to changes in the fader control voltage. In particular, as the slice level reaches near the top of the waveform, the figure rapidly becomes smaller, and the control of the size of the figure is not smooth. The purpose of the present invention is to eliminate the above-mentioned drawbacks, and to prevent deterioration of the S/N of a figure due to external noise such as power supply hum or internal noise such as thermal noise even in a figure using a parabolic waveform such as a circular figure. A clear figure is generated even when the figure is narrowed down to a small size, and when soft green or borderline green is added to the figure, the soft green width or borderline green width remains almost constant even when the slice level reaches near the top of the waveform. We aimed to provide a special effect waveform generator that can have a wide range of width, the size of the figure corresponds well to changes in the fader control voltage, and the size can be controlled more smoothly even if the figure is narrowed down to a small size. It is something to do.

The present invention will be explained in detail below using the drawings of one embodiment of the present invention.

FIG. 3 is a configuration diagram showing an embodiment of the present invention, in which a horizontal fundamental wave generation circuit 11 generates parabolic waves etc. at the timing of a horizontal synchronization signal, and a vertical fundamental wave generation circuit 11 generates parabolic waves etc. at the timing of a vertical synchronization signal. A generation circuit 12, a combination circuit 13 for mixing a horizontal fundamental wave and a vertical fundamental wave, a gain control circuit 14 for controlling the amplitude of the mixed fundamental wave outputted from the mixing circuit 13 by a fader control signal from an input terminal 16, and a gain control circuit 14 for controlling the amplitude of the mixed fundamental wave output from the mixing circuit 13. It is comprised of a comparison circuit 15 and an output terminal 17 that compare the level of the mixed fundamental wave with the level of the fader control signal from the input terminal 16 and output a special effect waveform. Parabolic waves and the like output from the horizontal and vertical fundamental wave generating circuits 1 1 and 12 are mixed by a mixing circuit 13 and amplitude-controlled by a feeder control signal from an input terminal 16 in a gain control circuit 14 .

It is preferable that the gain control circuit 14 clamps the top of the waveform as shown in the waveform diagram of FIG. 4, and changes the gain in A, C, and C directions according to the fader control signal. A gain control circuit having control characteristics as shown in FIG. 4, for example, inserts a clamping gate pulse whose tip has the same potential as the top of the fundamental wave into the horizontal planking section of the fundamental wave such as a parabolic waveform.
It can be easily configured by clamping the tip of the gate pulse inserted after gain control and clipping the voltage below a certain potential using a black ripper. An example of this configuration is shown in FIG. The gain-controlled mixed fundamental wave is sent to the input terminal 16 by the comparison circuit 15.
The signal is then compared with the level of the fader control signal, sliced by the fader control signal level value, and a special effect waveform for switching between a plurality of video signals is output from the output terminal 17.

Here, the relationship between the gain control characteristic of the gain control circuit 14 based on the fader control signal and the mixed fundamental wave slice level of the comparator circuit 15 is expressed as the slice level based on the fader control signal reaches near the top of a waveform such as a parabolic wave. If the gain of the gain control circuit 14 is increased, that is, the output waveform of the gain control circuit 14 is configured to change in the order of A → mouth → C as shown in FIG. 4, near the top of a waveform such as a parabolic wave, The waveform amplitude increases, and the slope of the waveform near the top becomes steeper in response to the increase in amplitude. Therefore, in a figure using a parabolic wave such as a circular figure, even if the figure is narrowed down to a small size, the S/N ratio of the figure is greatly improved and a clear figure can be generated. In addition, in the present invention, as mentioned above, the slope can be made steeper near the top of the waveform, so when adding soft green or borderline green to a figure using a parabolic wave such as a circular figure, the slice level is lower than that of the waveform. The width of the soft green or borderline green can be kept almost constant even when it reaches the top, and it is also possible to control the shape so that the size of the shape responds more smoothly to changes in fader control pressure than before. . In the embodiments described above, for convenience of explanation, the gain control circuit 14 was installed between the mixing circuit 13 and the comparison circuit 15; If a gain control circuit having the same circuit configuration as described above is installed in each of the sections 13, the same effects as described above can be obtained.

However, in this case, it is necessary to accurately match the control voltage versus gain characteristic curves of both the horizontal and vertical gain control circuits. As described in detail above, according to the present invention, in a figure using parabolic waves such as a circular figure, even if the figure is narrowed down to a small size, the S/S/ In addition to preventing N degradation and making the figure clearer, when soft green or borderline green is added to the figure, the soft green width or borderline green width remains almost constant even if the size of the figure is controlled by the fader control signal. It is possible to obtain a special effect waveform generator which can have a wide width and can perform graphic control in which the size of the graphic corresponds more smoothly to changes in the fader control voltage than in the past.

In addition, in the case of a figure other than a figure using a parabolic waveform such as a circular figure, such as a rhombus figure, by adding a switching circuit such as removing the gain control circuit in the embodiment, all the figures can have the above-mentioned effect. Of course.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a conventional special effect waveform generator, FIG. 2 is a waveform diagram for explaining the process of generating special effect waveforms in a subordinate special effect waveform generator, and FIG. 3 is a configuration diagram showing one embodiment of the present invention, FIG. 4 is a waveform diagram for explaining the characteristics of one embodiment of the gain control circuit in FIG. 3, and FIG. 5 is a diagram showing one implementation of the gain control circuit in FIG. FIG. 2 is a configuration diagram of a specific example of a gain control circuit in the example.

In the figure, 1, 11...... horizontal fundamental wave generation circuit, 2, 12...... vertical fundamental wave generation circuit, 3, 13
...Mixing circuit, 4, 15...Comparison circuit, 14...Gain control circuit, 18...Gate pulse insertion circuit, 19...Gain Control unit, 20・
...Clamp circuit, 21...Black clipper.

Ta-no-zu Ticket 3 Ticket 2 Kaya 4 Many diagrams

Claims (1)

[Claims] 1. A fundamental wave generation circuit that generates horizontal and vertical special effects, a mixing circuit that mixes the horizontal and vertical special effect fundamental waves, and a level of the mixed special effect fundamental wave output from the mixing circuit that is set to the level of the fader control signal. and a comparison circuit that outputs a special effect waveform by comparing the fader control circuit between the fundamental wave generation circuit and the mixing circuit or between the mixing circuit and the comparison circuit. A gain control circuit whose amplification degree changes depending on the signal is installed, and the gain of the gain control circuit is increased in response to the level of the fader control signal of the comparison circuit reaching near the top of a parabolic wave or the like. Features a special effects waveform generator.