JPS6339281A - Signal switching device - Google Patents

Abstract

PURPOSE:To decrease the number of input terminals and to reduce erroneous connections by providing a means which discriminates the presence or absence of a synchronizing signal in inputted signals and a control signal output means in a signal input system which is one system where two kinds of signals are selectively inputted and automatically switching an input destination based on the output of the control signal. CONSTITUTION:When a luminance signal 1S, a wide band chrominance signal 2S and a narrow band chrominance signal 3S are respectively inputted in input terminals 14-16, since the signal 1S is the one including a synchronizing signal, a synchronizing signal separation circuit 8 derives the synchronizing signal 8S. Thus the control signal generation circuit 9 outputs the control signal 9S and switches a switch box 13 in a connecting state illustrated with a dot-line in figure. According to the switching, an R output 1R, a G output 2G, a B output 3B and a synchronizing signal 8S outputted from a matrix circuit 10 are inputted in a video circuit 11. Thus one input system of two kinds of signals, the ones including synchronizing signal and the others not including synchronizing signal, is used in common, so that the necessary number of the input terminals can be sharply decreased and the erroneous connections can be removed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to, for example, a human-powered device for transmitting signals to a video circuit, and the input signal includes a synchronizing signal or the input signal does not include a synchronizing signal. The present invention relates to a signal switching device that automatically switches the destination of these two types of signals depending on whether the signal is not present or not.

[Prior Art] FIG. 3 is a block diagram showing the configuration of a conventional signal switching device when applied to a signal input device to a video circuit. In the same figure, (1), (2), (3).

(4), (5), (8), and (7) are input terminals, and (1) has a luminance signal (hereinafter referred to as Y signal).
(IY)), (2) is a broadband color signal (hereinafter referred to as
CW double signal (2W)), (3) is a narrowband color signal (hereinafter referred to as CM signal).

(2N)), (0 is an external synchronization signal (hereinafter, (4N)
(5) is a red primary color signal (hereinafter referred to as R signal, (5R)), (8) is a green primary color signal (
A blue primary color signal (hereinafter referred to as a B signal, referred to as (7B)) is input to G signal (hereinafter referred to as (8G)) and (7), respectively.

(8) is a synchronization signal separation circuit from which a synchronization signal (hereinafter referred to as (8S)) included in the Y signal is derived.

(8) is a control signal generation circuit, which includes the synchronization signal (8).
When S) is derived, a control signal (hereinafter referred to as (9S)) is output. (10) is a matrix circuit, which is inputted with the Y signal (IY) and the C signal (2).
W), CM double signal 3N) are matrix-exchanged, and the red primary color output (hereinafter referred to as R output, (IR)), the green primary color output (hereinafter referred to as G output, (2G)), and the blue primary color output (hereinafter referred to as (2G)), , B output, (denoted as (3B)) is derived. (11
) is a video circuit, and (12) is a converter for switching the destination of each of the above-mentioned signals.

Next, the operation of the signal switching device having the above configuration will be explained.

When the Y signal (IY), CW multiplied signal 2W), and CM multiplied signal 3N) are input from the above input terminals (1), (2), and (3), respectively, the Y signal (IY) is input to the synchronization signal separation circuit ( 8) and matrix circuit (lO), and CW
The double signal (2W) and the CN signal (3N) are processed by the matrix circuit (l
o). Y signal (IY) input to matrix circuit (10), CW multiplied signal 2), CM multiplied signal 3N
) is matrix-converted and R output (IR), G output (
2G), B output (3B) is derived and input to the converter (12), while Y input to the synchronization signal separation circuit (8)
The signal (IY) derives the synchronization signal (8S) included in this Y signal (IY). This derived synchronization signal (8S
) is input to the control signal generation circuit (9) and the converter (12), and the control signal generation circuit (8) outputs the control signal (9S). As a result, the converter (12) becomes connected as shown by the solid line in FIG.
Output (3B) is input.

Next, the R signal (5R), G signal (6G), and B signal (
7B) is input, the above control signal generation circuit (9)
does not output the control signal (9S), so the converter (1) does not output the control signal (9S).
2) is connected as shown by the dotted line in Figure 3, and the video circuit (11) receives the external synchronization signal (4S), R signal (5R), and G signal (6G) input from the input terminal (4). ,
A B signal (7B) is input.

[Problem to be Solved by the Invention 1] In the conventional signal switching device configured as above, the required number (N) of input terminals for inputting two types of signals is N=2on+1 where, n is the number of signals for each of the two types of signals.

For example, in the case of a signal input device to a video circuit as described above, N=2×3+1=7, and seven input terminals are required.

In addition, since the input system is divided into two systems, there is a drawback that it is easy to make mistakes in the JLI system.

This invention was made to solve the above problems, and it is possible to reduce the number of input terminals, and
It is an object of the present invention to provide a signal switching device that can completely eliminate connection errors.

[Means for Solving the Problems] A signal switching device according to the present invention determines whether a signal input to one signal input system includes a synchronization signal, and determines whether the signal input to one signal input system includes a synchronization signal. In some cases, the apparatus is characterized by providing means for automatically switching the destination of an input signal by outputting a control signal.

[Operation] In this invention, only when the input signal is a signal including a synchronization signal, the synchronization signal is separated and derived to output a control signal, and the outputted control signal is used to determine the destination of the input signal. Automatically switches depending on the type.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a signal switching device for a video circuit according to an embodiment of the present invention, and in this figure, the same components as those shown in FIG. 3 are given the same reference numerals. .

In Figure 1, (14), (15), (1B
) is an input terminal, and (14) is a Y signal or an R signal.
The signal (IS), (15) is a CW multiplied signal or a G signal (
2S), (1B) is a CN signal or B signal (3S)
are selectively input. (13) is a converter that switches the destination of each signal.

The operation of the signal switching device having the above configuration will be explained.

R signal (IS), G signal (2S), and B signal (3S) to input terminals (14), (15), and (1G), respectively.
is input, since (Is) is a signal that does not include a synchronization signal, the synchronization signal separation circuit (8) inputs the synchronization signal (8S
), therefore, the control signal generation circuit (9) does not output the control signal (9S), the converter (13) is in the connected state as shown by the solid line in Figure 1, and the R signal (5R),
G signal (6G), B signal (7B) and external synchronization signal (
4S) is directly input to the video circuit (11).

Next, input terminals (14), (15), (1B
), Y signal (IS), CN signal (25), C
When the N signal (3S) is input, since (IS) is a signal containing a synchronization signal, the synchronization signal separation circuit (8) derives the synchronization signal (8S). As a result, the control signal generation circuit (9) outputs a control signal (9S), and the converter (1) outputs a control signal (9S).
3) to the connection state shown by the dotted line in FIG.

Along with this, the Y signal, CN signal, and CN signal are input to the matrix circuit (10), and this matrix circuit (10) is inputted to the matrix circuit (10).
R output (IR), G output (2G) output from 0),
B output (3B) and synchronization signal (8S) are connected to the video circuit (
11).

The input section of the video circuit (11) is configured as shown in FIG. 2, for example.

However, in FIG. 2, the signal source impedance to which the R signal (IR) and R output (5R) are input is set to 75Ω, so that each resistor (R).

The resistance values of (R1) and (R2) are determined according to the following equation. In other words, in addition to the signal input device to the video circuit as described in detail in the above embodiment, the present invention also provides a device for selectively inputting two types of signals, and a destination according to the type of each input signal. It can be applied to any device that requires switching.

[Effects of the Invention] As described above, according to the present invention, the presence or absence of a synchronization signal in an input signal is determined, and the destination of the input signal is automatically switched based on the determination result. It is possible to share input systems for two types of signals, including those with signals and those without signals, greatly reducing the number of input terminals required, and also when the inputs are divided into two systems. It is possible to eliminate connection mistakes that can easily occur.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a signal switching device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of an input section of a video circuit according to an embodiment of the present invention, and FIG. 3 is a conventional signal switching device. FIG. 2 is a block diagram showing the configuration of the device. (4)...Input terminal for external synchronization signal, (8)...Synchronization signal separation circuit, (9)...Control signal generation circuit, (1
0)...Matrix circuit, ('11)...Video circuit, (13)...Converter, (14), (15)
, (1B)...Input terminal. In addition, in the figures, the same reference numerals indicate the same parts.

Claims (2)

[Claims] (1) Determine the presence or absence of a synchronization signal among the signals input to one signal input system into which two types of signals, one containing a synchronization signal and one without a synchronization signal, are selectively input. A means for outputting a control signal when the determining means determines that a synchronizing signal is present, and a means for automatically switching the destination of the input based on the output of the control signal are connected. Signal switching device. (2) One signal input system into which the above two types of input signals are selectively input consists of multiple input terminals, among which:
The signal switching device according to claim 1, wherein only the signal input from one input terminal includes a synchronization signal.