JPS6243980A - Video mixture amplifier - Google Patents

Abstract

PURPOSE:To obtain an excellent video mixture characteristic by providing a video mixture circuit, a gain control circuit and a control signal circuit. CONSTITUTION:Since in a video mixture circuit 3, a signal is mixed by a control output 11 from a control input 4, the signal supplied to a video input terminal 1 outputs a ratio of a fader voltage C to a sum of fader voltages C, D and a signal supplied to a video input terminal 2 outputs the ratio of the fader voltage D to the sum of the fader voltages C, D and they are mixed and outputted. A signal multiplied by the sum of the fader voltages C, D in a gain control circuit 5 and supplied to the video input terminal 1 in an output terminal 7 to obtain a mixture signal multiplied by the fader voltage C and the signal supplied to the video input terminal 2 to obtain the mixture signal multiplied by the fader voltage D. Thereby, an excellent video mixture characteristic can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video mixing amplifier used in a television studio transmission system or the like.

[Conventional technology]

Conventionally, there have been two types of video mixing amplifiers of this type: one using one fader and the other using two faders. As shown in the block diagram of Fig. 4, the one-fader one-way system is as follows:
It consists of a mixing amplifier 20 having two video signal input signals 1°2 and a control input signal 21 for controlling the mixing ratio, and the mixing ratio can be changed as shown in the characteristic diagram in FIG. 3 by the control input voltage. can. In other words, the fader voltage is set to E
If you change it from 0 to 1 like this, you get Ei*Reaigo A.

B is output according to the mixing ratios F and G. The feature of this one-fader type is that it has excellent cross-fade characteristics when mixing two video signals where the sum of the two video signals is 100%.
This was impossible in cases where the sum of two video signals did not equal 100%.

On the other hand, as shown in the block diagram of FIG. 5, the 2-wire, 7-wire one type has two gain control circuits 22 each having one video signal terminal 1 (2) and a gain control input signal 25 (26). .2
This is a mixing amplifier that mixes the outputs from the three video signals in a mixing circuit 24 and outputs a mixed output of two video signals from an output terminal 7. The feature of this method is that it is possible to obtain a mixed output in which the phase of the two video signals is not more than 100, but the normal sum is 10(l).
The problem was that the cross-fade characteristics during mixing were not good.

[Problem that the invention seeks to solve]

The conventional mixing increase 1f mentioned above! 1iif! The sum is 100
It has the disadvantage of not being able to satisfy the two requirements of having good properties when the ratio is 100%, and also being able to mix without the ratio being 100%.

The object of the present invention is to solve these drawbacks and provide a mixing amplifier which has excellent cross-fade characteristics and can also provide mixing characteristics with less than 100 points.

[Failure to solve the problem]

The video mixing amplifier of the present invention includes a video mixing circuit that outputs two video signal input signals by changing the mixing ratio using a first control signal, and a video mixing circuit that changes the mixing ratio of two video input signals using a first control signal, and outputs the output from the video 9R mixer using a gain control signal. a gain control circuit for controlling the gain control circuit;
and a control signal circuit that outputs the control signal as one fader voltage for two 7-degree voltages nK, and outputs the second control signal as the overlap of the two fader voltages. .

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

This embodiment includes a video mixing circuit 3 having two video input signals 1.2 and a control input signal 4, a gain control circuit 5 waiting for a control input signal 6, and a control voltage having an external control input signal 8.9. It is composed of a conversion circuit IO.

Next, the operation of this embodiment will be explained. The voltages supplied to the external control input signals 8 and 9 are fader voltages C1D as shown in the characteristic diagram of FIG.
, I) is output, and the sum of the fader voltages C1) is converted into a control output 12 and output.

In the video mixing circuit 3, the control voltage (control output 11) from the control unit 4 is mixed as shown in FIG.
The signal supplied to the video input signal 2 is mixed with the ratio of the fader voltage C to the sum of the seven fader voltages C21) and output.

When this fader is linked, fader voltage C, D
Since the phase line of is always rlJ from Fig. 2, the control output 1
1, the fader voltage C is "1", and the control output 12 is "1".
is present. At this time, "1" is supplied to the control input signal 6, the gain of the gain control circuit 3 is always "1", and the fader voltage C is supplied to the control input signal 4, so that the first
The block diagram in the figure is equivalent to the one-fader, one-way video mixing amplifier shown in FIG.

In addition, when the faders are separated, the video input signal 1.
The signal supplied to 2 is output to a video mixing circuit 3. Further, the gain control circuit 5 multiplies the signal to the sum of the fader voltage C1D, so the signal supplied to the video input signal 1 is multiplied by the fader voltage C, and the signal supplied to the video input signal 2 is multiplied by the fader voltage C to the output terminal 7. A signal mixed twice as much as the fader voltage is obtained.

This is like the two-fader single system shown in FIG. 5, which allows two video input signals to be controlled independently and can be mixed so that the sum does not add up to 100. For example, fader voltage 13 = 1. When fader voltage 14=1, two video input signals 1 and 2
The signals supplied to the 6 signals are mixed at 100% each.

〔Effect of the invention〕

As explained above, the present invention connects a video mixing circuit and a gain adjustment circuit in series, and uses the sum of kneader voltages as a control signal, thereby achieving cross-fade characteristics during mixing where the sum becomes 100%. It is possible to obtain excellent video mixing characteristics in which the sum is not 100%.

[Brief explanation of drawings]

Figure 1 is a block diagram of a video mixing amplifier according to an embodiment of the present invention, Figure 2 is a characteristic diagram of fader voltage depending on fader position, and Figure 3 is a diagram showing the relationship between control voltage and mixing ratio in the video mixing circuit. Figure 4 is a block diagram of a conventional one-fader single-type video and vibration mixing amplifier, and Figure 5 is a block diagram of a conventional
FIG. 2 is a block diagram of the present one-fader type video mixing amplifier. 1.2...Video input signal, 3.20...
・Video mixing circuit, 4, 6, 21, 25. 26...
・Control input signal, 5.22, 23... Gain control circuit, 7... Output terminal, 8.9... External control input signal, 10...・Control signal conversion circuit,
11, 12...Control output, 24...Mixing circuit.

Claims (1)

[Claims] a video mixing circuit that outputs two video signal input signals by changing the mixing ratio thereof using a first control signal; a gain control circuit that performs gain control of the output of the video mixer using a second control signal; a control signal circuit that outputs one control signal as one fader voltage for the sum of two fader voltages, and outputs the second control signal as the sum of the two fader voltages.