JP2615770B2 - Video signal synthesizer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal synthesizing device, and more particularly to a video signal synthesizing device for synthesizing and outputting a video signal used in a television studio device.

[Conventional technology]

Conventionally, as shown in FIG. 3 as a first example, this type of video signal synthesis has input terminals 31-1, 31-2, 32-1, 32-2, switching circuits 33, 34, 35, 36, 41, 42, 43, 44, 47, 48, 55, 56, phase adjustment circuits 37, 38, 39, 40, 49, 50, 53, 54, gain control circuits 45, 46, control signal generation circuits 51, 52, It consisted of output terminals 57 and 58.

Input video signals are supplied to the input terminals 31-1, 31-2, 32-1, and 32-2.

The input video signals of the input terminals 31-1, 31-2 are supplied to the respective switching circuits 33, 34 together with the output signals of the gain control circuit 46.

The switching circuits 33 and 34 are switched according to system conditions, and output signals are respectively switched by switching circuits 41 and 42 and a phase adjustment circuit 37,
To 38.

The switching circuits 41 and 42 are switched under the same system conditions as the switching circuits 33 and 34, and are supplied to the gain control circuits 45, respectively.

The control signal generation circuit 51 supplies a control signal to the switching circuit 47 and the phase adjustment circuit 49. The switching circuit 47 is switched under the same system conditions as the switching circuits 41 and 42, and supplies a control signal to the gain control circuit 45. Further, the gain control circuit 45 supplies an output signal to the switching circuit 55 and the phase adjustment circuit 53. The output signal of the switching circuit 55 is sent to the output terminal 57 first.
Are supplied as output signals of the system. Each phase adjustment circuit is used to add a required phase to an input video signal in order to match a phase between two inputs to be switched.

Similarly, the input video signals of the input terminals 32-1 and 32-2 are switched by the switching circuits 35 and 3 for switching the output signal of the gain control circuit 45.
6, is supplied to the switching circuits 43 and 44 via the phase adjusting circuits 39 and 40.

This output signal is supplied to the gain control circuit 46. The gain control circuit 46 includes a phase adjustment circuit 50,
It is controlled by a control signal passed through the switching circuit 48. Then, the output signal is supplied to the switching circuit 56 via the phase adjustment circuit 54. This output signal is output to the output terminal 58 as a second system output signal.

As a second example of this type of video signal synthesizing apparatus, as shown in FIG. 5, input terminals 61-1, 61-2, 62-1, 62-2, switching circuits 69, 70, 73, 74, Adjustment circuits 67, 68, gain control circuit 6
3, 64, 71, control signal generation circuits 65, 66, 72, and output terminals 75, 76. The input video signal is input terminals 61-1 and 61-2.
Is supplied to the gain control circuit 63 via Also, input terminal 62
The input video signal from -1, 62-2 is supplied to a gain control circuit 64.

Gain control circuits 63 and 64 are control signal generation circuits 65 and 66, respectively.
And supplies the output signal to the phase adjusting circuits 67 and 68 and the switching circuits 69 and 70.

Output signals of the switching circuits 69 and 70 are supplied to a gain control circuit 71 and controlled by a control signal generation circuit 72. Switching circuit
The switches 73 and 74 output the signals of the phase adjustment circuits 67 and 68 and the gain control circuit 71 to the switching output terminals 75 and 76 as first and second output video signals.

[Problems to be solved by the invention]

According to the first example, when a system in which gain control circuits 45 and 46 are continuously connected as shown in FIG. 4 is realized according to the first example, a switching circuit 43 serving as an input of the gain control circuit 46 is provided. When the video system up to is viewed from the input terminal 31-1,
Because the switching circuits 33, 41, 35, 43 and four switching circuits are passed,
There are drawbacks such as deterioration of video characteristics and increase in delay of video phase. Further, since there are many switching circuits for switching the video system, there is a drawback that the control method becomes complicated.

According to the second example, as shown in FIG. 5, the control signal generation circuit 72 for controlling the gain control circuit 71 needs to be provided separately from the control signal generation circuits 65 and 66, which complicates the control. There is a disadvantage that.

[Means for solving the problem]

A video signal synthesizing apparatus according to the present invention includes a first video signal synthesizing unit that receives a plurality of input video signals and performs gain control independently on each of them to synthesize them.
And a second gain control circuit, a first switching circuit that receives the plurality of input video signals and switches and outputs two of them, two outputs of the first switching circuit, and the first and second gain control circuits. A second switching circuit that outputs two outputs obtained by switching between the outputs of the gain control circuits of the first and second gain control circuits; and a first switching circuit that outputs the first and second gain control circuits input to the second switching circuit. A first phase adjustment circuit for adjusting the phases of two outputs of the switching circuit so as to match each other, and the first and second switching circuits.
A first and a second control signal generating circuit for controlling the gain of the gain control circuit, a third switching circuit for switching and outputting one of the outputs of the first and second control signal generating circuits, A second phase adjustment circuit that adjusts the phase of the output of the third switching circuit so as to match the phase of the output of the second switching circuit; and receives two outputs of the second switching circuit. A third gain adjustment circuit that performs gain control on the output of the second phase adjustment circuit and synthesizes and outputs the output; and outputs the outputs of the first and second gain control circuits and the output of the third gain control circuit, respectively. A fourth switching circuit for switching, and an output phase of the first and second gain control circuits input to the fourth switching circuit is adjusted so as to match a phase of an output of the third gain control circuit. With third and fourth phase adjustment circuits It is made.

〔Example〕

 Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a connection system diagram in the operation of the embodiment of FIG.

The configuration of the embodiment shown in FIG. 1 comprises gain control circuits 5 and 6 as first and second gain control circuits, switching circuits 3 and 4 constituting first switching circuit 101, and second switching circuit 102. , The control signal generating circuits 7 and 8 as the first and second control signal generating circuits, the third switching A switching circuit 11 as a circuit, a phase adjustment circuit 12 as a second phase adjustment circuit, a gain control circuit 17 as a third gain control circuit, switching circuits 18 and 19 forming a fourth switching circuit,
And phase adjustment circuits 15 and 16 as a fourth phase adjustment circuit.

 Next, the operation of the embodiment of the present invention will be described.

The input video signal is supplied to the gain control circuit 5 as a first gain control circuit and the switching circuits 3 and 4 constituting the first switching circuit 101 via the input terminals 1-1 and 1-2. The input video signals from the input terminals 2-1 and 2-2 are supplied to a gain control circuit 6 as a second gain control circuit and switching circuits 3 and 4.

The outputs of the switching circuits 3 and 4 are respectively connected to the first phase adjustment circuit 1
03 and the second switching circuit 10 via the phase adjustment circuits 9 and 10.
The signals are supplied to the switching circuits 13 and 14 forming the second circuit.

The gain control circuits 5 and 6 are controlled by control signal generation circuits 7 and 8 of the first and second control signal generation circuits, respectively, and output the output signals to the phase adjustment circuits 15 and 16 of the third and fourth phase adjustment circuits. And to the switching circuits 13 and 14.

Output signals of the switching circuits 13 and 14 are supplied to a gain control circuit 17 which is a third gain control circuit. A switching circuit 11 serving as a third switching circuit switches control signals output from the control signal generating circuits 7 and 8 serving as first and second control signal generating circuits, and switches a phase adjusting circuit of the second phase adjusting circuit. Supply to 12. The gain control circuit 17 is controlled by this output.

The switching circuits 18 and 19 constituting the fourth switching circuit 104 switch the output signals of the phase adjustment circuits 15 and 16 and the gain control circuit 17 to output terminals 20 and 21 as first and second output video signals. Output.

With this video system, as shown in FIG.
When the input video signals of the input terminals 1-1, 1-2 and 2-2 are synthesized by connecting the terminals 5 and 17 continuously and output to the output terminal 21, the input terminal 1
Focusing on the input video signal of -1, only one stage of the switching circuit 13 is required, and the video system is simplified. As a result, it is possible to prevent the characteristic deterioration of the image of the output signal, and to realize a system other than that shown in FIG. 2 by an easy control method. Since the control signal for controlling the gain control circuit 17 is a control signal by switching the output of the control signal generation circuits 7 and 8, control is facilitated by that amount.

In the present embodiment, the gain control circuits 5 and 6 handle two signals. However, it is apparent that the same effect can be obtained by a gain control circuit that handles three or more signals.

〔The invention's effect〕

As described above, according to the present invention, the first (second) gain control circuit performs the first (second) control signal generation circuit to control the gain of the two input video signals using the first (second) control signal generation circuit. The second (first) system signal, which has been phase-adjusted by the phase adjustment circuit via the switching circuit and the second (first) system signal via the switching circuit, is newly added via the switching circuit to the second (second) signal by the third gain control circuit. By performing gain control by the control signal generation circuit of 1), there is an effect that the video system is shortened, deterioration of characteristics is remarkably improved, and the control system becomes extremely easy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a video signal synthesizing apparatus according to the present invention, FIG. 2 is a connection system diagram of the operation of the video signal synthesizing apparatus shown in FIG. 1, and FIG. FIG. 4 is a block diagram of the operation of the video signal synthesizing device of FIG. 3, and FIG. 5 is a block diagram of a second example of the conventional video signal synthesizing device. 1-1, 1-2, 2-1, 2-2 ... input terminals, 3, 4 ... (first
) Switching circuit, 5... (First) gain adjustment circuit, 6.
(Second) gain adjustment circuit, 7 (first) control signal generation circuit, 8 (second) control signal generation circuit, 9, 10, ...
(First) phase adjustment circuit, 11... (Third) switching circuit,
12 ... (second) phase adjustment circuit, 13,14 ... (second)
Switching circuit, 15... (Third) phase adjustment circuit, 16... (Fourth) phase adjustment circuit, 17... (Third) gain control circuit,
18, 19 ... (fourth) switching circuit, 20, 21 ... ... output terminals.

Claims (1)

(57) [Claims] 1. A first and a second gain control circuit for receiving a plurality of input video signals and controlling the gains independently of each other and combining them, and receiving two or more of the plurality of input video signals.
A first switching circuit for switching and outputting two outputs, and a second switching circuit for outputting two outputs obtained by switching between two outputs of the first switching circuit and outputs of the first and second gain control circuits. A switching circuit, and a first circuit for adjusting the outputs of the first and second gain control circuits input to the second switching circuit so that the phases of the two outputs of the first switching circuit coincide with each other. A phase adjustment circuit, first and second control signal generation circuits for controlling the gains of the first and second gain control circuits, and switching between one of the outputs of the first and second control signal generation circuits A third switching circuit for outputting, a second phase adjustment circuit for adjusting the phase of the output of the third switching circuit to match the phase of the output of the second switching circuit, and the second switching circuit The two outputs of the circuit are received and output from the second phase adjustment circuit. A third gain adjustment circuit that performs gain control by combining the outputs, and a fourth switching circuit that switches between the outputs of the first and second gain control circuits and the output of the third gain control circuit, respectively. Third and fourth phase adjustment circuits for adjusting the phases of the outputs of the first and second gain control circuits input to the fourth switching circuit so as to match the phase of the output of the third gain control circuit. Wherein a combined output of the plurality of input video signals is obtained from the fourth switching circuit.