JPH0334714B2 - - Google Patents

Description

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

Conventionally, this type of television special effect waveform generator generates fundamental waves with horizontal and vertical periods as shown in Figure 1, synthesizes both fundamental waveforms in a waveform synthesis circuit, and then synthesizes them in a clip circuit. Clipping was performed according to the fader control signal level and an effect waveform was output. However, such waveform generators are limited in the types of waveforms that can be generated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a special effect waveform generator that can generate waveforms that are difficult to generate with conventional configurations without requiring a significant increase in configuration.

According to the present invention, there is provided a circuit that generates fundamental waves of horizontal and vertical periods, a waveform synthesis circuit that synthesizes these two fundamental waves, and an absolute waveform that receives the synthesized waveform and obtains a signal folded back based on a predetermined level. A value circuit, a level conversion circuit that receives the output of the absolute value circuit and shifts the level, and a clip circuit that clips the output of the level conversion circuit according to the fader control signal level, and a special effect is output from the clip circuit. A special effects waveform generator is obtained for obtaining waveforms.

Next, the present invention will be described in detail with reference to the drawings of an embodiment of the present invention. FIG. 2 is a diagram showing an embodiment of the present invention, in which horizontal and vertical period fundamental wave generation circuits 1 and 2 generate horizontal and vertical period fundamental waves, which are added in a waveform synthesis circuit 3. Or perform a synthesis process such as non-additive mixing. To explain with reference to FIG. 3, for example, if the waveform shown in FIG. 3a is obtained as the output of the waveform synthesis circuit 3,
Next, the signal is turned back by the absolute value circuit 5 based on the reference value V _R shown in the figure, and its output becomes as shown in FIG. 3b. This corresponds to taking the reference value V _R as zero, and taking the absolute value above it as positive and below it as negative. The absolute value output b undergoes waveform level conversion in a level conversion circuit 6 in order to make the waveform level equal to that of a in the figure, and is converted as shown in c in the figure. Furthermore, since the direct current component of the waveform is not equal to that shown in FIG. 3A, the waveform shown in FIG.
As the output of the subtraction circuit 7, a waveform whose waveform level and DC component are equal to the output of the waveform synthesis circuit 3 is obtained.If this waveform is clipped by the clipping circuit 4 according to the fader control signal level, the effect of the present invention can be obtained. Waveform output can be obtained.

When a conical waveform is obtained as the output of the waveform synthesis circuit 3, there is a case where it is inputted as it is to the clip circuit 7, and a case where the absolute value circuit 3, a level conversion circuit 5,
The appearance of the effect waveform generated when the signal is passed through the subtraction circuit 6 and the effect waveform are shown in FIGS. 4a and 4b, respectively. The effect waveform on the screen is indicated by diagonal lines. The arrows in the effect waveform diagram indicate the direction in which the effect changes when the clip level is changed by the fader control signal.

It is clear that even if the level conversion circuit 5 and the subtraction circuit 6 are removed in FIG. 2, it is possible to obtain the same effect as the effect waveform depending on how the fader control signal level is determined. It is also possible to output a soft waveform as an effect waveform.

As described above, the present invention has the effect of easily generating a waveform that has not been seen before by performing absolute value processing on the synthesized waveform and clipping it based on the fader control signal level.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the prior art, FIG. 2 is a block diagram showing an example of the present invention, and FIG.
FIG. 4 is a diagram showing an example of the effect waveform output. In the figure, 1...horizontal periodic fundamental wave generation circuit, 2...
Vertical periodic fundamental wave generation circuit, 3... waveform synthesis circuit,
4... Clip circuit, 5... Absolute value circuit, 6...
Level conversion circuit, 7...subtraction circuit. In Figure 3, a
...Example of the output waveform of the waveform synthesis circuit 3, b...Example of the output waveform of the absolute value circuit, c...Example of the output waveform of the level conversion circuit, d...Example of the output waveform of the subtraction circuit.
In Figure 4, a...The output of the waveform synthesis circuit is a conical waveform, and the effect waveform when this is clipped, b... The second
The figure shows the effect waveform when the output of the waveform synthesis circuit is conical.

Claims (1)

[Claims] 1. an effect fundamental wave generation circuit that generates effect waveform fundamental waves in horizontal and vertical television scanning periods, respectively; a synthesis circuit that synthesizes effect waveform fundamental waves in the horizontal and vertical periods from said effect fundamental wave generation circuit; and said synthesis circuit. The circuit includes a folding waveforming circuit that receives an output waveform of the circuit and generates a waveform folded back based on a predetermined level, and a clipping circuit that clips the output waveform of the folding waveforming circuit according to a fader control signal level. A special effect waveform generator characterized by extracting a special effect waveform.