JPH0619383U - Video input signal switching device - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the size and assembly workability of a video input signal switching device. A YC conversion circuit 1 for converting a composite signal into a YC separate signal, an RGB decoder for converting the YC separate signal into an RGB signal, and a luminance signal for converting the composite signal into a sync signal. And a sync separation circuit 3 for extracting the signal, and selectively input any one of a composite signal, a YC separate signal, and an RGB signal from the input terminals I1 to I4,
The first and second switches SW1 and SW2 are used to switch the connection states so as to convert the signals into RGB signals through the circuits.
And third to sixth switches SW3 to SW6 are provided, and the switching control circuit 4 controls switching of each switch in accordance with a selection signal of three types of signals. [Effect] The number of input terminals can be minimized, the device can be downsized, and the wiring material can be reduced to improve the assembly workability.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a video input signal switching device, and more particularly, it can selectively input two or more kinds of various video input signals of a composite signal, a YC separate signal, and an RGB signal, which can be converted into an RGB signal and taken out. And a video input signal switching device.

[0002]

[Prior art]

 A composite signal, a YC separate signal, and an RGB signal are used as a video input signal of a video device, and there is a device which takes out as an RGB signal even if any of these signals is input.

FIG. 9 shows a conventional circuit that can input the above three types of signals and extract them as RGB signals. In FIG. 9, the composite signal input terminal Icv is connected to the input part of the YC separation circuit 1, and the luminance and chroma signals output from the YC separation circuit 1 are two-position selection type Y signal switching. The switches SW 1 and the C signal changeover switch SW 2 are adapted to be input to the selection contacts H 1 and H 2, respectively.

The luminance signal input terminal Iy of the YC separate signal is connected to the other selection contact L1 of the Y signal changeover switch SW1, and the chroma signal input terminal Ic is connected to the other selection contact L2 of the C signal changeover switch SW2. The common terminals of both changeover switches SW1 and SW2 are connected to the input section of the RGB decoder 2. Further, the nodes of the common terminal of the Y signal changeover switch SW1 and the RGB decoder 2 are connected to the input section of the sync separation circuit 3, and the sync signal is separated by the sync separation circuit 3 from the branched luminance signal and taken out. .

The synchronization signal is input to one selection contact H3 of the two-position selection type synchronization signal changeover switch SW3. Further, since each chroma signal from the YC separation circuit 1 and the chroma signal input terminal Ic is input to the C signal changeover switch SW2, the luminance signal and the chroma signal are transmitted through the RGB decoder 2 to the RGB signal. B signals are converted. The respective signals of R, G and B are input to the selection contacts H4 to H6 of one of the two position selection type R, G and B signal changeover switches SW4 to SW6 respectively provided correspondingly. Has been done. The RGB signal R / G / B signal input terminals Ir / Ig / Ib are connected to the other selection contacts L4 to L6 of the R / G / B signal changeover switches SW4 to SW6, respectively, and the sync signal is input. The terminal Is is connected to the other selection contact L3 of the synchronization signal changeover switch SW3.

The switches SW1 to SW6 are selectively switched by the switching control circuit 4. In the composite signal input state, the state is as shown in the figure. In the YC separate signal input state, if the switches SW1 and SW2 are switched to the other selection contact points L1 and L2, respectively, and the switches SW3 to SW6 remain in the state shown in the figure. In the RGB signal input state, the switches SW3 to SW6 are switched to the other selection contacts L3 to L6, respectively, and the switches SW1 and SW2 may be arbitrary.

In the conventional video input signal switching circuit configured as described above, since the input terminals corresponding to the respective signals are provided as well shown in the figure, each input terminal and the device internal There is a problem in that the number of wires to the circuit board increases and assembly workability tends to deteriorate.

[0008]

[Problems to be solved by the device]

 In view of the above problems of the prior art, a main object of the present invention is to provide a video input signal switching device capable of reducing the number of video signal input terminals.

[0009]

[Means for Solving the Problems]

 For this purpose, according to the present invention, two or more kinds of video signals of three kinds of video signals of RGB signals, YC separate signals and composite signals are individually converted into one predetermined kind of video signal. The signal conversion means, at least one common input terminal provided for inputting the two or more types of video signals to one terminal, and the signal processing path in the signal conversion means are provided for the two or more types of video signals. Achieved by providing a video input signal switching device, characterized in that it has a signal switching means for switching to each type and selectively inputting the two or more types of video signals to the common input terminal. To be done. In particular, a YC separation circuit for converting a composite signal into a YC separate signal, a sync separation circuit for separating a sync signal from the YC separate signal, an RGB decoder for converting the YC separate signal into an RGB signal, and a first ~ Converts a composite signal input to the fourth input terminal and any one of the first to fourth input terminals into an RGB signal by the YC separation circuit, the synchronization separation circuit, and the RGB decoder. Output the first state, and the luminance and chroma signals of the YC separate signal input to any two of the first to fourth input terminals are converted into RGB signals by the sync separation circuit and the RGB decoder. The second state and the R, G, and B signals of the RGB signals input to the first to fourth input terminals and the synchronization signal are output as they are. A signal switching circuit capable of selectively switching any one of the three states, and switching the signal switching circuit according to any one of the composite signal, YC separate, and RGB selection signals from the input signal selection means. A video input signal switching device characterized by being provided with a switching control circuit for controlling, or a YC separation circuit, a synchronization separation circuit, an RGB decoder, and first and second input terminals. , The first and second input terminals, the composite signal input to any one of the first and second input terminals is converted into an RGB signal by the YC separation circuit, the synchronization separation circuit, and the RGB decoder, and is output. The state and the luminance and chroma signals of the YC separate signal input to the first and second input terminals are converted into RGB signals by the sync separation circuit and the RGB decoder and output. A signal switching circuit capable of selectively switching any one of the second states, and switching of the signal switching circuit according to any one of the composite / YC separate selection signals from the input signal selection means. A video input signal switching device, which is provided with a switching control circuit for controlling, or a sync separation circuit, an RGB decoder, first to fourth input terminals, and the first to fourth The first state and the first to fourth states in which the luminance and chroma signals of the YC separate signal input to any two of the input terminals are converted into RGB signals by the sync separation circuit and the RGB decoder and output. Signal switching circuit capable of selectively switching any one of the R, G, and B signals of the R GB signal input to the input terminal of R and the synchronization signal as they are, and the signal switching circuit. And a switching control circuit for controlling switching according to any one of the YC separate / RGB selection signals from the input signal selection means, or a video input signal switching device, or A YC separation circuit, a synchronization separation circuit, an RGB decoder, first to fourth input terminals, and a composite signal input to any one of the first to fourth input terminals to the YC separation circuit. A first state converted into an RGB signal by the sync separation circuit and the RGB decoder and output, and R, G, and B signals of RGB signals input to the first to fourth input terminals and a sync signal A signal switching circuit capable of selectively switching any one of the second states in which the signal is output as it is, and one of the composite / RGB selection signals from the input signal selecting means for the signal switching circuit. It is advisable to provide a switching control circuit for switching control according to the above.

[0010]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing a first embodiment of a video input signal switching device to which the present invention is applied, and the same parts as those of the embodiment of FIG. 9 described in the prior art are the same. The symbol is attached and the detailed explanation is omitted. In this embodiment, four input terminals I1 to I4 are provided as the first to fourth input terminals, and a composite signal, a luminance signal, and an R signal correspond to each other at the input terminal I1. Input is made appropriately according to the connection state of the signal line to be connected. The chroma signal and the G signal are similarly appropriately input to the input terminal I2. Similarly, the B signal is input to the input terminal I3, and the synchronization signal is input to the input terminal I4 as appropriate.

In this circuit, the input terminal I1 is connected to the input section of the YC separation circuit 1 and also to the selection contact L1 of the Y signal changeover switch SW1, and further to the R signal changeover switch SW4. It is also connected to the selection contact L4. The input terminal I2 is connected to the selection contact L2 of the C signal changeover switch SW2 and also connected to the selection contact L5 of the G signal changeover switch SW5. The input terminal I3 is connected to the selection contact L6 of the B signal changeover switch SW6, and the input terminal I4 is connected to the selection contact L3 of the synchronous signal changeover switch SW3. The connection states of the other selection switches and common terminals of the switches SW1 to SW6, the YC separation circuit 1, the RGB decoder 2, the sync separation circuit 3, and the switching control circuit 4 are the same as in the conventional example.

In the application of this device, as described above, the four input terminals I1 to I4 are made to share a part of the composite signal, the YC separate signal, and the RGB signal, so that the connector is It is preferable to use a common shape or a structure having four corresponding output terminals on the video signal output device side. As the video signal output device, for example, one having a structure shown in FIG. 2 can be considered.

In FIG. 2, each of the RGB signals and the synchronization signal are input as input signals, and are input to the YC conversion circuit 5, respectively, and are converted into YC separate signals. The YC separate signal is input to the MIX circuit 6 and converted into a composite signal. The composite signal output of the MIX circuit 6 is input to one selection contact H7 of the two-position selection type first switch SW7, and the luminance signal from the YC conversion circuit 5 is input to the other selection contact L7 of the first switch SW7. The common terminal of the first switch SW7 is connected to one selection contact H8 of the similar two-position selection type second switch SW8, and the common terminal of the second switch SW8 is connected to the first output terminal O1. It is connected to the.

The signal line of the R signal is connected to the other selection contact L2 of the second switch SW8, and the chroma signal output of the YC conversion circuit 5 is input to one selection contact H9 of the third switch SW9, The G signal is input to the other selection contact L9 of the 3-switch SW9. The common terminal of the third switch SW9 is connected to the second output terminal O2 of the main output device. Also, the B signal line is connected to the third output terminal O 3, and the signal line of the synchronization signal is connected to the output terminal Os.

The switches SW7 to SW9 described above are selectively switched by the output signal switching control circuit 7. That is, when the first switch SW7 selects the H7 side and the second switch SW8 selects the H8 side, the composite signal is output from the first output terminal O1. Next, when the first switch SW7 is selected on the L7 side, the second switch SW8 is selected on the H8 side, and the third switch SW9 is selected on the H9 side, from the first output terminal O1. A luminance signal is output, and a chroma signal is output from the second output terminal O2, resulting in a YC separate signal output state. Then, when the second switch SW8 is selected on the L8 side and the third switch SW9 is selected on the L9 side, the RGB signals are output from the first to third output terminals O1 to O3. become.

Therefore, the output signal switching control circuit 7 selects by connecting the first to third output terminals O1 to O3 and the input signals I1 to I3 respectively and connecting the output terminal Os and the input terminal I4. Each video output signal according to the selected state is selectively output from each output terminal O1 to O3.Os to each input terminal I1 to I4. Then, in the video input signal switching device, the switches SW1 to SW6 are selectively switched by the switching control circuit 4 in the same manner as in the conventional example according to the selection state of each video output signal.

An example of the switching control circuit 4 applied to this device is shown in FIG. The switch control circuit 4 is connected to respective one ends of push button type selection switches SWc, SWy and SWr as input signal selection means for selecting composite, YC separate and RGB signals as video input signals respectively. Has been done. Each of the selection switches SWc, SWy, SWr is a normally open switch having one end connected to a constant voltage terminal via a resistor and the other end grounded. When the contact is closed by pressing an arbitrary selection switch, the L level signal which is the selection signal and the H level signal when the contact is open in the figure are input to the switching control circuit 4, respectively.

One end of the selection switch SWc that selects the composite signal is connected to the set terminal -S of the first flip-flop FF1, and one end of the selection switch SWy that selects the YC separate signal is reset by the first flip-flop FF1. Connected to terminal-R. Further, one ends of the selection switches SWc and SWy are connected in parallel to a pair of input terminals of the AND circuit AD. One end of the selection switch SWr for selecting the RGB signal is connected to the set terminal -S of the second flip-flop FF2, and the output terminal of the AND circuit AD is connected to the reset terminal -R of the second flip-flop FF2. There is. The switches SW1 and SW2 are switched according to the output from the output terminal Q of the first flip-flop FF1, and the switches SW3 are switched according to the output from the inverting output terminal -Q of the second flip-flop FF2. ~ SW6 can be switched.

Next, a procedure for switching each video input signal will be described below. When the selection switch SWc is pressed, both switches SW1 and SW2 are switched to the H1 and H2 sides by the H level output from the output terminal Q of the first flip-flop FF1, and the inverting output terminal of the second flip-flop FF2. The switches SW3 to SW6 are switched to the sides H3 to H6 by the H level output from -Q. Therefore, when the composite signal is input from the first input terminal I1, the YC separation circuit 1 in FIG. Is separated into luminance and chroma signals at the same time, the sync signal is taken out at the sync separation circuit 3 and converted into RGB signals at the RGB decoder 2, and the sync signal is sent via the switch SW3 to the switches SW4 to SW4. Each signal of R, G, B is taken out from SW6.

When the selection switch SWy is pressed, the first switch SW1 is switched to the L1 side and the second switch SW2 is switched to the L2 side by the L level output from the output terminal Q of the first flip-flop FF1. Since the switches SW3 to SW6 are switched to the H3 to H6 side by the H level output from the inverting output terminal -Q of the flip-flop FF2, the luminance signal is output from the first input terminal I1 and the chroma signal is input from the second input terminal I2. When inputted, the sync signal is taken out by the sync separation circuit 3 and converted into an RGB signal by the RGB decoder 2 so that the sync signal and the R, G, B signals are taken out in the same manner as above. become.

When the selection switch SWr is pressed, the output state of the output terminal Q of the first flip-flop FF1 is arbitrary, but the L level output from the inverting output terminal −Q of the second flip-flop FF2 causes each switch SW3 ~ SW6 is switched to the L3 to L6 side, so that the R signal from the first input terminal I1, the G signal from the second input terminal I2, the B signal from the third input terminal I3, and the fourth input terminal I4 are synchronized. When the signals are input, the respective signals are directly output as they are, that is, the synchronization signal is directly output through the switch SW3, and the R, G, and B signals are output directly from the switches SW4 to SW6.

In this way, by controlling the switching of the switches SW1 to SW6, it is possible to input three types of video input signals only with the four input terminals I1 to I4, and to extract them as RGB signals. it can. There are various combinations of video signal inputs to the input terminals I1 to I4. There are 12 combinations of luminance and chroma signals of the YC separate signal, and there are 24 combinations of RGB signal. Since there are four combinations of signals, 1152 combinations of each input signal are possible.

FIG. 4 shows another embodiment of the switching control circuit 4 when the rotary switch 8 is used as the selection switch. As shown in FIG. 4, the common terminal of the rotary switch 8 is branched and connected to the first and second voltage detection circuits 9 and 10 provided in the switching control circuit 4.

The rotary switch 8 is provided with three selection contacts, one of the composite selection contacts RSc is connected to the constant voltage terminal Vcc, and the YC separate selection contact RSy is connected between the constant voltage terminal Vcc and the ground. Is connected to a node between both resistors R connected in series, and the RGB selection contact RSr is grounded. Both the switches SW1 and SW2 are switched according to the output of the first voltage detection circuit 9, and the other switches SW3 to SW6 are switched together according to the output of the second voltage detection circuit 10.

In this embodiment, the constant voltage Vcc is selected when the composite selection contact RSc is selected, and the partial voltage (Vcc / 2) is selected when the YC separate selection contact RSy is selected, and the RGB selection contact RSr is selected. When is selected, the ground voltage is applied to the first and second voltage detection circuits 9 and 10, respectively. The first voltage detection circuit 9 switches both switches SW1 and SW2 to the H1 and H2 sides when the voltage input is equal to or higher than the first predetermined voltage (a value that exceeds Vcc / 2 to some extent), and when the voltage is less than that. It outputs a signal to switch both switches SW1 and SW2 to the L1 and L2 sides. The second voltage detection circuit 10 switches the other switches SW3 to SW6 to the H3 to H6 side when the voltage is higher than the second predetermined voltage (for example, Vcc / 3) lower than Vcc / 2, and the voltage is lower than that. In this case, a signal for switching the switches SW3 to SW6 to the L3 to L6 side is output. The first and second voltage detection circuits 9 and 10 can be composed of comparators such as operational amplifiers.

In the example of FIG. 4 as well, similar to the above-described embodiment, the switches SW1 to SW6 can be appropriately switched to realize the switching state of the video input signal according to the selected state of the rotary switch 8. It should be noted that the selection switch is not limited to the form of each of the above embodiments, and various mechanical switches such as a slide switch and a toggle switch can be used.

FIG. 5 shows a second embodiment according to the present invention. The same parts as those in the above embodiment are designated by the same reference numerals and detailed description thereof will be omitted. In the second embodiment, the composite signal and the YC separate signal are selectively input. As shown in the figure, the input terminal I1 is connected to the YC separation circuit 1 and the selection contact L1 of the switch SW1, and the input terminal I2 is connected to the selection contact L2 of the switch SW2. . The luminance and chroma signals from the YC separation circuit 1 are connected to the selection contacts H1 and H2 of both switches SW1 and SW2. The connection between the common terminals of both the switches SW 1 and SW 2 and the RGB decoder 2 and the sync separation circuit 3 is the same as in the above embodiment, but in the present embodiment, the RGB decoder 2 and the sync separation circuit 3 are connected. The synchronizing signal and the R, G, B signals are directly taken out.

The switches SW1 and SW2 are selectively switched by the switching control circuit 11. The switching control circuit 11 of the second embodiment is based on the structure shown in FIG. The circuit is configured so that only SW1 and SW2 can be switched. For example, in the case corresponding to FIG. 5, only the flip-flop FF1 may be provided and the two selection switches SWc and SWy may be similarly connected. In this way, when both the switches SW1 and SW2 are switched to the H1 and H2 sides, the first state in which the composite signal is input from the first input terminal I1 is entered, and the switches are switched to the L1 and L2 sides. In this case, the luminance signal is input from the first input terminal I1 and the chroma signal is input from the second input terminal I2, and the video input signals of the composite signal and the YC separate signal are selected. It can be selectively switched and extracted as an RGB signal.

FIG. 6 shows a third embodiment according to the present invention. The same parts as those in the above-mentioned embodiment are designated by the same reference numerals and detailed description thereof will be omitted. In the third embodiment, the YC separate signal and the RGB signal are selectively input. As shown in the figure, the input terminal I1 is connected to the RGB decoder 2, the sync separation circuit 3, and the selection contact L4 of the switch SW4, and the input terminal I2 is connected to the RGB decoder 2 and the selection contact L5 of the switch SW5. Connected to and respectively. The input terminal I3 is connected to the selection contact L6 of the switch SW6, and the input terminal I4 is connected to the selection contact L3 of the switch SW3. Further, the connection state between the RGB decoder 2 and the sync separation circuit 3 and each other selection contact of each of the switches SW3 to SW6 is the same as that in the above-mentioned embodiment. In this embodiment, each connection is the same as in the first embodiment. The synchronization signal and the R, G, B signals are respectively taken out from the switches SW3 to SW6.

The switches SW3 to SW6 are selectively switched by the switching control circuit 12. The switching control circuit 12 of the third embodiment is similar to that of the second embodiment, and the switches SW3 to SW6 are the same. Are configured so that they can be switched together. In this way, when each of the switches SW3 to SW6 is switched to the H3 to H6 side, the first input terminal I1 receives the luminance signal and the second input terminal I2 receives the chroma signal. When switched to the L3 to L6 side, the second input terminal inputs the R signal from the first input terminal I1, the second input terminal I2 receives the G signal, and the third input terminal I3 receives the B signal. In this state, the video input signals of the YC separate signal and the R GB signal can be selectively switched and taken out as RGB signals.

FIG. 7 shows a fourth embodiment according to the present invention. The same parts as those in the above embodiment are designated by the same reference numerals and detailed description thereof will be omitted. The fourth embodiment is a case where the composite signal and the RGB signal are selectively input. As shown in the figure, the input terminal I1 is connected to the YC separation circuit 1 and the selection contact L4 of the switch SW4, and the input terminal I2 is connected to the selection contact L5 of the switch SW5. . The input terminal I3 is connected to the selection contact L6 of the switch SW6, and the input terminal I4 is connected to the selection contact L3 of the switch SW3. The luminance and chroma signals from the YC separation circuit 1 are directly connected to the RGB decoder 2, and the luminance signal is branched and input to the sync separation circuit 3. Further, the connection state between the sync separation circuit 3 and the RGB decoder 2 and each other selection contact of each of the switches SW3 to SW6 is the same as that in the above-mentioned embodiment. In this embodiment, each switch is the same as in the first embodiment. The sync signal and the R, G, B signals are respectively taken out from SW3 to SW6.

The switches SW3 to SW6 of this embodiment are also selectively switched by the switching control circuit 13, but like the third embodiment, the switches SW3 to SW6 are configured to be switchable together. It has been done. In this way, when each of the switches SW3 to SW6 is switched to the H3 to H6 side, the first state in which the composite signal is input from the first input terminal I1 is entered, and the switches are switched to the L3 to L6 sides, respectively. In such a case, the composite signal becomes the second state in which the R signal is input from the first input terminal I1, the G signal is input from the second input terminal I2, and the B signal is input from the third input terminal I3. It is possible to selectively switch the respective video input signals of the RGB signal and the RGB signal and take out as the RGB signal.

Further, FIG. 8 shows a modified embodiment of the device capable of inputting three kinds of video input signals as in the case of the first embodiment. The same parts as those in the embodiment are designated by the same reference numerals. And its detailed description is omitted. In FIG. 8, the input terminal I1 is connected to the input section of the YC separation circuit 1 and also to the selection contact L3 of the switch SW3. The input terminal I2 is connected to the selection contact L6 of the switch SW6. The input terminal I3 is connected to the selection contacts L2 and L5 of the switches SW2 and SW5, and the input terminal I4 is connected to the selection contacts L1 and L4 of the switches SW1 and SW4. The connection states of the other selection switches of the switches SW1 to SW6, the common terminal, the YC separation circuit 1, the RGB decoder 2, the sync separation circuit 3, and the switching control circuit 4 are the same as those in the above-described embodiment.

In this embodiment, a composite signal and a synchronizing signal are input to the input terminal I1, a B signal is input to the input terminal I2, a chroma signal and a G signal are input to the input terminal I3, and a luminance signal is input to the input terminal I4. The R signal and the R signal are selectively input. When the switches SW1 to SW6 are selectively switched by the switching control circuit 4, the synchronizing signals and the R, G, and B signals are taken out from the switches SW3 to SW6 as in the first embodiment.

In each of the above embodiments, the case where the output video signal is the RGB signal is shown, but other signals such as the YC separate signal or the composite signal may be output. In this case, as the signal converting means, a YC converting circuit for converting an RGB signal into a YC separate signal or a MIX circuit for converting a YC separate signal into a composite signal may be combined with each of the signal converting circuits described above. The switching means can be easily realized by combining and changing each switching element based on the signal switching circuit.

[0037]

[Effect of device]

 As described above, according to the present invention, only two input terminals are provided in the case of switching between two types of input states of the YC separate signal and the composite signal, and when the RGB signal is included, it is necessary as the RGB signal. Only by providing four input terminals, more than two types of video input signals can be input and output as RGB signals, so the number of input terminals can be minimized and the circuit board inside the device can be used. The wiring material connecting to the input connector can be reduced, the assembling workability can be improved, and the device can be downsized.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a video input signal switching device to which the present invention is applied.

FIG. 2 is a video output signal switching circuit diagram for outputting various video signals to a video input signal switching device.

FIG. 3 is a circuit diagram showing a switching control circuit.

FIG. 4 shows another embodiment of the switching control circuit.

FIG. 5 is a circuit diagram showing a second embodiment of the video input signal switching device.

FIG. 6 is a circuit diagram showing a third embodiment of the video input signal switching device.

FIG. 7 is a circuit diagram showing a fourth embodiment of a video input signal switching device.

FIG. 8 is a circuit diagram showing a modification of the first embodiment of the video input signal switching device.

FIG. 9 is a circuit diagram showing a conventional example of a video input signal switching device.

[Explanation of symbols]

 1 YC separation circuit 2 RGB decoder 3 Synchronization separation circuit 4 Switching control circuit 5 YC conversion circuit 6 MIX circuit 7 Output signal switching control circuit 8 Rotary switch 9 First voltage detection circuit 10 Second voltage detection circuit 11 to 13 Switching control circuit

Claims (5)

[Scope of utility model registration request] 1. A signal converting means for individually converting two or more kinds of video signals of three kinds of video signals of RGB signals, YC separate signals and composite signals into one predetermined kind of video signal, and the two kinds. At least one common input terminal provided for inputting the above video signal into one terminal and the signal processing path in the signal conversion means are switched for each of the two or more types of video signals,
A video input signal switching device, comprising: a signal switching unit for selectively inputting more than one type of video signal to the common input terminal. 2. A YC separation circuit for converting a composite signal into a YC separate signal, a sync separation circuit for separating a sync signal from the YC separate signal, and an RGB decoder for converting the YC separate signal into an RGB signal. The composite signal input to any one of the first to fourth input terminals and the first to fourth input terminals is input to the Y
A first state in which the C separation circuit, the synchronous separation circuit, and the RGB decoder convert to an RGB signal and output the RGB signal, and YC input to any two of the first to fourth input terminals
A second state in which the luminance and chroma signals of the separate signal are converted into RGB signals by the synchronization separation circuit and the RGB decoder and output, and R, G, and G of the RGB signals input to the first to fourth input terminals. A signal switching circuit capable of selectively switching any one of the third states in which the respective signals of B and the synchronizing signal are output as they are, and the signal switching circuit is a composite / YC separate / input from the input signal selecting means.
A switching device for a video input signal, comprising a switching control circuit for switching control according to any one of RGB selection signals. 3. A YC separation circuit for converting a composite signal into a YC separate signal, a sync separation circuit for separating a sync signal from the YC separate signal, and an RGB decoder for converting the YC separate signal into an RGB signal. A composite signal input to the first and second input terminals and any one of the first and second input terminals is converted into an RGB signal by the YC separation circuit, the synchronization separation circuit, and the RGB decoder. And a second state in which the luminance and the chroma signal of the YC separate signal input to the first and second input terminals are converted into an RGB signal by the synchronization separation circuit and the RGB decoder. A signal switching circuit capable of selectively switching any one of the states, and the signal switching circuit for the composite / Y signal from the input signal selecting means. A switching device for a video input signal, which is provided with a switching control circuit for performing switching control according to any one of the selection signals of C separate. 4. A sync separation circuit for separating a sync signal from a YC separate signal, an RGB decoder for converting the YC separate signal into an RGB signal, first to fourth input terminals, and the first to fourth parts. The first state and the first to fourth states in which the luminance and chroma signals of the YC separate signal input to any two of the input terminals are converted into RGB signals by the sync separation circuit and the RGB decoder and output. A signal switching circuit capable of selectively switching any one of the R, G, and B signals of the RGB signals input to the input terminal and the second state in which the synchronization signal is output as it is; YC separate / RG from the selection means
A switching device for a video input signal, comprising a switching control circuit for switching control according to any one of the selection signals B. 5. A YC separation circuit for converting a composite signal into a YC separate signal, a sync separation circuit for separating a sync signal from the YC separate signal, and an RGB decoder for converting the YC separate signal into an RGB signal. The composite signal input to any one of the first to fourth input terminals and the first to fourth input terminals is input to the Y
The C separation circuit, the synchronous separation circuit, and the RGB decoder convert the RGB signal into the first state and output the R signal of the RGB signal input to the first to fourth input terminals.
Second output of G and B signals and synchronization signals as they are
A signal switching circuit capable of selectively switching any one of the above states, and switching for controlling the switching of the signal switching circuit in accordance with any one of the composite / RGB selection signals from the input signal selecting means. A switching device for a video input signal, which is provided with a control circuit.