JPS6222313B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a special effects waveform generator for television special effects, and more particularly to a stripe wipe special effects waveform generator.

Conventionally, in order to generate a special effect waveform signal for so-called stripe wipe, in which the boundaries of the screen change sequentially over several lines as shown in Fig. 1 a, b, and c, the method shown in Fig. 2 a is used. It was obtained by superimposing the vertical periodic fundamental wave shown in FIG. 2 with the horizontal periodic fundamental wave shown in FIG. 2b and comparing it with the fader voltage in a comparison circuit. In this method, as shown in FIG. 2b, it is necessary to make the amplitude of the horizontal period smaller than the vertical period fundamental wave. Therefore, it becomes susceptible to the influence of mixed noise. This can be easily understood from the fact that as the number of lines increases, for example to 8 lines, the influence of noise increases.

Furthermore, when obtaining a so-called soft edge waveform with blurred boundaries, it is not possible to uniformly blur all boundaries because a stepped fundamental wave is used.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a special effects waveform generator that generates special effects waveforms whose boundaries move over several lines without these problems except for the drawbacks of the prior art.

In the special effect waveform generator of the present invention, the determination of stripe connections is performed digitally accurately and stably, and the comparison operation that creates changes due to the fader control voltage is always obtained by comparison with a signal with a large amplitude. Therefore, unlike in the past, when the number of lines is increased, the boundary will not become unstable due to noise.

Next, the present invention will be described in detail with reference to the drawings showing one embodiment of the present invention. FIG. 3 shows an embodiment of the present invention. In the figure, there are first a vertical periodic fundamental wave generation circuit 1 and a horizontal periodic fundamental wave generation circuit 2 for generating a fundamental wave according to a special effect. The outputs of the fundamental wave generation circuits 1 and 2 are sent to comparison circuits 3, 4 and 5, and compared with respective predetermined slice levels to form special effect waveforms. The special effect waveforms are combined by logic operation circuits 6 and 7 and output from an output terminal 8. These logic operation circuits 6 and 7 are as described in the "Digital Special Effects Generator" (Material TBS No. 38-1) presented at the Television System and Circuit Study Group of the Television Society on May 30, 1975. , can be configured with a non-additive mixing (NAM) circuit. In FIG. 3, the vertical periodic fundamental wave is sent to comparison circuits 3 and 5, and the horizontal periodic fundamental wave is sent to comparison circuit 4.

On the other hand, the control voltage from the fader 9 that controls the movement of the special effect waveform is supplied to a sampling hold circuit 10 and an analog-to-digital (A/D) conversion circuit 12.
sent to. A sampling pulse with a vertical period is supplied to the sample hold circuit 10 from a terminal 11. The sample hold circuit 10 compensates for delays caused by the A/D conversion circuit 12 and the like. A/D
A vertical synchronization pulse is supplied to the conversion circuit 12 from a terminal 13. A/D converter 12 converts the control voltage from fader 9 into a multi-bit digital code. Fader data division control circuit 14
is the digital code from the A/D conversion circuit 12,
It receives the row number selection control signal from the terminal 20 and controls the digital-to-analog conversion circuits 15, 16, and 17.

The operation of the fader data division control circuit 14 will be explained next. Now, for example, when performing the special effect shown in FIG. 1, it is necessary to move three lines of stripes with one movement of the fader 9. Therefore,
The fader division control circuit 14 is the A/D conversion circuit 1
By dividing the output data of 2 into 3 stages,
Output data that changes stepwise in three steps is sent to the D/A converter 15. The D/A converter 15 converts it into an analog signal, and the mixing circuit 18 mixes it with the fader control voltage from the sampling and holding circuit 10.
A sawtooth wave with three cycles is created per operating period. The mixing circuit 18 outputs a sawtooth wave whose period corresponds to the number of stripes that divide the screen per operation of the fader 9, so that the amplitude becomes smaller as the number of lines increases. Therefore, the output of the mixing circuit 18 is amplified by the gain control circuit 19. Since the degree of amplification can be set constant according to the number of rows, the row number selection control signal from the terminal 20 is also supplied to the gain control circuit 19.

The output of the gain control circuit 19 is sent to the comparator circuit 4 and becomes the slice level of the horizontally periodic fundamental wave. Therefore, the output _φ1 of the comparator circuit 4 becomes an effect waveform in which the operation of the screen rising from the left end is repeated three times per one operation of the fader 9. In the operation of this comparator circuit 4, even if the number of rows increases, the amplitude of the output of the gain control circuit 19 does not become small, so that an accurate and stable effect waveform can be obtained.

Further, the fader data division control circuit 14 outputs data indicating slice levels corresponding to the positions on the screen of the stripes that divide the screen, and sends them to the D/A converters 16 and 17. D/
The signals indicating the slice level converted into analog signals by the A converters 16 and 17 are sent to the comparators 3 and 17, respectively.
5 to slice the vertically periodic fundamental wave. Therefore, the outputs φ ₂ and φ ₄ of the comparator circuits 3 and 5 respectively become waveforms that divide the screen at predetermined height points on the screen. D/A converter 16, 17
The data to the fader data division control circuit 14 is predetermined according to a special effect, that is, a form of stripe wipe, and is controlled by the fader data division control circuit 14.

Figure 4 shows the outputs φ ₁ and φ of comparator circuits 4, 3, and 5.
₂ , φ ₄ , output φ ₃ obtained by ANDing output φ ₁ and output φ ₂ in logic operation circuit 6, and output φ obtained by ORing output φ ₃ and output φ ₄ in logic operation circuit 7.
₅ are displayed in correspondence with the effects on the screen. Outputs of comparison circuits 4, 3, 5 φ ₁ , φ ₂ , φ
Of course, if you use other combinations of ₄ , you will get even different effects.

It is clear that when the number of boundaries formed by stripes increases, the number of outputs from the fader division control circuit 14, D/A converters 16 and 17, and comparison circuits 3 and 5 should be increased accordingly. be. In addition, in the explanation of the embodiment, a sawtooth wave is used as the horizontal periodic fundamental wave and the vertical periodic fundamental wave, and the horizontal periodic fundamental wave is sliced by the fader control voltage, but various other embodiments can be created. . For example, if a triangular wave is used for each fundamental wave, a stripe wipe that changes from two places at the same time can be created. Moreover, if a signal with an integral multiple of the fundamental frequency is used as the fundamental wave, even more special effects can be created.

In other words, the horizontal and vertical fundamental wave generating circuits generate fundamental waves of different shapes, fundamental waves of fundamental periods, harmonics, and waves of different polarities, and all of these signals are passed through a switch to each comparator circuit 3, 4. ,5
The slice levels of the D/A converters 16 and 17, which are controlled according to the special effect, the combination of outputs of each comparison circuit, and the D/A converter 15
If the switching data of the switching device is stored in the memory included in the fader data division control circuit as well as data such as the width of the staircase wave output from the fader, various stripe wipes can be automatically created.

FIG. 5 is a diagram showing the relationship among the fader control voltage, the output of the D/A converter 15, and the output of the gain control circuit 19 in the embodiment of the present invention. In Fig. 5, a is the fader control voltage, and b is the D/A converter 15.
The output c is the output of the gain control circuit 19, the vertical axis shows the voltage, and the horizontal axis shows the rotation angle of the fader. The output of the gain control circuit 19 provides a control voltage that changes just by operating the fader once, as if the fader had been operated several times.

Further according to the invention, using a plurality of comparators,
One of the important features is that the fundamental wave and the control voltage that determines the slice level are compared, and the outputs are logically non-additively combined, so it is possible to blur the entire border formed by the stripes. be.

FIG. 6 is a diagram showing an example of a special effect obtained by the present invention, which changes from a to f in FIG. 6. A change from a to f can be made with a single fader operation. In this case, it is natural that the number of comparison circuits is increased compared to that shown in the embodiment.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a special effect of a stripe wipe, FIG. 2 is a diagram for explaining how to make a conventional stripe wipe, FIG. 3 is a diagram showing the configuration of an embodiment of the present invention, and FIG. The figure shows a part of the waveform of the main part of FIG. 3, and FIG. 5 shows the relationship among the fader control voltage, the output of the D/A converter 15, and the output of the gain control circuit 19 in FIG. , FIG. 6 is a diagram showing an example of special effects obtained by the present invention. In the figure, 1...vertical periodic fundamental wave generation circuit,
2...Horizontal periodic fundamental wave generation circuit, 3...Comparison circuit, 4...Comparison circuit, 5...Comparison circuit, 6...Logic operation circuit, 7...Logic operation circuit, 8...Output terminal, 9... ...Fader, 10...Sampling hold circuit, 11...Sampling pulse input terminal, 12...Analog-to-digital conversion circuit, 13...
...Conversion timing pulse input terminal, 14...Fader data division control circuit, 15...Digital-analog conversion circuit, 16...Digital-analog conversion circuit, 17...Digital-analog conversion circuit, 18...Mixing circuit, 19... gain control circuit,
20...Line number control signal input terminal.

Claims (1)

[Claims] 1. When creating a stripe wipe special effect waveform, at least one horizontal comparison circuit that compares special effect waveforms synchronized with the horizontal period at a predetermined level to obtain an effect waveform that vertically divides the television screen; at least one vertical comparison circuit that compares special effect waveforms synchronized with each other at a predetermined level to obtain an effect waveform that horizontally divides the television screen; and a stripe circuit that combines the outputs of the horizontal comparison circuit and the vertical comparison circuit. a non-summing mixing circuit for obtaining a wipe effect signal; means for generating a first slice level that varies stepwise from row to row of the stripes; means for generating a varying second slice level;
means for synthesizing the slice levels of and supplying the synthesized slice level to one of the horizontal comparison circuit and the vertical comparison circuit, and generating a third slice level according to the position of the stripe on the television screen. A special effects waveform generator comprising means for supplying the third slice level to the other of the horizontal comparison circuit and the vertical comparison circuit.