JPH07221616A - Signal processor - Google Patents

Abstract

PURPOSE:To eliminate the need of a switching operation by a user by constituting an input signal selection means with a logic circuit whose output is controlled by the presence/absence of input signals from a first or second signal source and a changeover switch. CONSTITUTION:When a positive and negative balanced signal source 2 is connected, in an R signal system for instance, positive polarity and negative polarity synchronizing signals are inputted from input terminals 5 and 6 to a NOR circuit 21. Then, since the positive polarity and negative polarity synchronizing signals inputted to the NOR circuit 21 are a common-mode and when one becomes an 'H' level when the other is an 'L' level, the output signals of the NOR circuit 21 becomes the 'L' level at all times. Then, a switch 12 receives the switching signals of the 'L' level, is switched to an L terminal side and outputs digital R signals outputted by an attenuator 11 to an R signal processing block 15. That is, signals for which a prescribed processing is performed to input signals are automatically selected and supplied to the R signal processing block 15 of a next stage and synchronizing signals required for the processing of the signals are simultaneously supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing device such as a video signal processing device to which a positive and negative digital video signal which is a positive / negative balanced signal and an analog video signal which is a single phase signal are input. More specifically, the present invention relates to a switching circuit that automatically switches a signal path according to the type of an input signal.

[0002]

2. Description of the Related Art FIG. 9 is a circuit diagram showing a conventional video signal processing device, showing a case where a positive / negative balanced signal source is connected. The figure shows digital R, G input from the positive / negative balanced signal source. , B signals, only the digital R signal system is shown. In the figure, 1 is a video signal processing device, 2 is a positive / negative balanced signal source, 3 is an input terminal for a positive digital R signal, 4 is an input terminal for a negative digital R signal in phase with the positive digital R signal, and 5 is Positive sync signal input terminal, 6 negative sync signal input terminal, 7 single-phase signal input terminal, 8
Is a positive / negative balanced signal processing block, 9 is a first subtractor, 10
Is a second subtractor, 11 is an attenuator (ATT), 12 is a switch, the output signal of the attenuator 11 is input to the L terminal side,
A single-phase signal is input to the other H terminal side. Reference numeral 13 denotes a user selection switch, and the switch 12 and the user selection switch 13 constitute a signal switching circuit 14. Reference numeral 15 is an R signal processing block and 16 synchronization signal processing block.

Next, the operation will be described. The positive digital R signal from the positive / negative balanced signal source 2 is input to the input terminal 3, and the negative digital R signal is input to the input terminal 4. The first subtractor 9 receives the input positive digital R
The negative digital R signal is subtracted from the signal, and the digital R signal in which the in-phase noise components included in both digital R signals are canceled is output to the attenuator 11. Since the level of this digital R signal is usually 3 VPP or higher,
Usually, in order to match the analog signal level which is about 0.7 VPP, it is attenuated to about 0.7 VPP by the attenuator 11 and output to the L terminal of the switch 12.

When the positive / negative balanced signal source 2 is connected, the user depresses the user selection switch 13, so that an "L" level switching signal is input to the switch 12 and L
Switching to the terminal side, the digital R signal is input to the R signal processing block 15.

FIG. 10 shows a conventional video signal processing apparatus 1
Shows the case where a single-phase signal source is connected. 1
Reference numeral 7 denotes a single-phase signal source, and the input terminal 7 is supplied with an analog R signal from the single-phase signal source 17.

Next, the operation will be described. In this case, since the user does not press the user selection switch 13, the switch 1
An "H" level switching signal is input to 2 to switch to the H terminal side, and an analog R signal is supplied to the R signal processing block 15.

[0007]

Since the conventional video signal processing apparatus is constructed as described above, it is necessary to provide a user selection switch and switch the digital signal by manual operation, which is troublesome to handle. was there.

The present invention has been made for the purpose of solving the above-mentioned problems, and when the signal source is connected to the video signal processing device, if the signal source is a positive / negative balanced signal source, it is automatically detected. Video signal processing for selecting the output signal of the subtracter 1 and processing the signal, and when the signal source is a single-phase signal source, automatically selecting the input single-phase signal and processing the signal. The purpose is to obtain the device.

[0009]

The signal processing apparatus according to the present invention selects the input signal when a signal is input from the first signal source and selects the input signal when the signal is input from the second signal source. Is provided with input signal selecting means for selecting this input signal and transmitting it to a common signal processing circuit, and the output of this input signal selecting means is controlled by the presence or absence of the input signal from the first or second signal source. It is composed of a circuit and a changeover switch controlled by an output signal of the logic circuit.

Further, when the positive / negative balanced signal forming the first signal source is input through the first subtractor, this input signal is selected and the single-phase signal forming the second signal source is input. Input signal switching circuit for selecting this input signal and transmitting it to a common signal processing circuit, and synchronization for inputting the positive / negative balanced synchronizing signal constituting the first signal source through the second subtractor. The signal processing block is provided, and the input signal switching circuit is a logic circuit to which the positive / negative balanced synchronization signal is input, and is controlled by the output signal of this logic circuit. When the positive / negative balanced synchronization signal is input, the positive / negative balanced signal is selected. , And a switch for selecting a single-phase signal when the positive / negative balanced synchronization signal is not input.

Further, the input terminal of the first signal source and the input terminal of the second signal source are shared.

Further, there is provided a level setting means for fixing the input terminal of the logic circuit to the L level or the H level when the signal is not inputted from the first signal source.

The level setting means is composed of a ground circuit for grounding the input terminal of the logic circuit or a grounded pull-down resistor. The grounding circuit is configured to be grounded via the connection terminal of the connector provided on the second signal source side.

The level setting means is composed of a circuit for connecting the input terminal of the logic circuit to the H level power supply or a pull-up resistor connected to the H level power supply.

[0015]

The logic circuit according to the present invention includes the first or second
The output is controlled by the presence / absence of an input signal from the signal source, and the changeover switch is controlled by the output signal of this logic circuit.

Further, the switch is controlled by the output signal of the logic circuit to which the positive / negative balanced synchronization signal is input, the positive / negative balanced signal is selected when the positive / negative balanced synchronization signal is input, and the positive / negative balanced synchronization signal is input. If not, single-phase signal is selected.

When the level setting means does not input a signal from the first signal source, the input terminal of the logic circuit is fixed to the L level or the H level.

[0018]

【Example】

Example 1. First Embodiment FIG. 1 is a circuit diagram showing a first embodiment of the present invention, showing a case where a positive / negative balanced signal source is connected. In the figure, the same reference numerals as those in FIG. 9 denote the same or corresponding portions, and 21 denotes a logical sum negation circuit (hereinafter,
In the “NOR circuit”), the positive polarity sync signal and the negative polarity sync signal are input from the input terminals 5 and 6, and the subtracted signal is output to the sync signal processing block 16.

Next, the operation will be described. Since the positive polarity synchronizing signal and the negative polarity synchronizing signal input to the NOR circuit 21 are in phase, when one is at “L” level, the other is at “H” level, and therefore the output signal of the NOR circuit 21 is always It becomes the "L" level. The switch 12 receives this "L" level switching signal and switches to the L terminal side, and the attenuator 11
To the R signal processing block 15.

According to the first embodiment, the positive / negative balanced signal source 2
When the output signal of is input to the signal processing device 1, a signal obtained by subjecting the input signal to a predetermined process is automatically selected and the R signal of the next stage is selected without the user performing an operation such as signal selection. It is supplied to the processing block 15 and, at the same time, the synchronization signal necessary for processing this signal.

FIG. 2 shows a case where a single-phase signal source 18 is connected to the signal processing device 1 of the first embodiment. In the figure, the same reference numerals as those in FIGS. 1 and 10 denote the same or corresponding portions, and 22 denotes an L level setting circuit,
It is provided in the single-phase signal source 18 and is connected to the input terminals 5 and 6 via the connection cable 19 to fix both terminals to the “L” level.

Next, the operation will be described. Since the two input signals of the NOR circuit 21 are both fixed at "L" level, the output signal thereof becomes "H" level. Therefore, the switch 12 is switched to the H terminal side in response to the "H" level switching signal, and the analog R signal input from the input terminal 7 is supplied to the R signal processing block 16.

According to the first embodiment, when the output signal of the single-phase signal source 18 is input to the signal processing device 1, the input signal is automatically output without any operation such as signal selection by the user. It is selected and supplied to the R signal processing block 15 in the next stage.

Example 2. FIG. 3 is a circuit diagram showing a second embodiment of the present invention, showing a case where a single-phase signal source 18 is connected. In the figure, the same reference numerals as those in FIG. 2 denote the same or corresponding portions, 23 is an AND circuit (hereinafter referred to as “AND circuit”), 24 is an H level setting circuit, and an input terminal is provided via a connection cable 19. 5 and 6 and fix the input terminals 5 and 6 to "H" level.

Next, the operation will be described. Since the two input signals of the AND circuit 23 are both at "H" level, the output signal thereof is at "H" level. Therefore, the switch 12
Is switched to the H terminal side in response to this "H" level switching signal, and the analog R signal input from the input terminal 7 is
It is output to the R signal processing block 15.

According to the second embodiment, similarly to the first embodiment, when the output signal of the single-phase signal source 18 is input to the signal processing device 1, this input is performed without any operation such as signal selection by the user. The signal is automatically selected and supplied to the synchronization signal processing block 15 in the next stage.

Example 3. FIG. 4 is a circuit diagram showing a third embodiment of the present invention and shows a case where a single-phase signal source 18 is connected. In the figure, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions, and 25 is a connector which is connected to the input terminal of the signal processing device 1 and inputs the analog R signal of the single-phase signal source 18 to the input terminal 7. To do. 26 is an L level setting circuit, 27 is a ground terminal provided in the signal processing device 1, and when the connector 25 is connected to the signal processing device 1, the input terminals 5 and 6 are connected to the ground terminal 27 via the L level setting circuit 26. It is connected and the input terminals 5 and 6 are fixed to the “L” level.

Next, the operation will be described. Since the two input signals of the NOR circuit 21 are both at "L" level, the output signal thereof is at "H" level. Therefore, the switch 12
Is switched to the H terminal side in response to this "H" level switching signal, and the analog R signal input from the input terminal 7 is
It is output to the R signal processing block 15.

According to the third embodiment, when the connector 25 is connected to the signal processing device 1, the signal input from the single-phase signal source 18 is automatically selected and supplied to the synchronization signal processing block 15 at the next stage. It

Example 4. FIG. 5 is a circuit diagram showing a fourth embodiment of the present invention and shows a case where a positive / negative balanced signal source 2 is connected. In the figure, the same reference numerals as in FIG. 1 denote the same or corresponding portions, and 28 is an L level setting circuit, which is a pull-down resistor 29 for grounding the input terminal
And a pull-down resistor 30 for grounding the input terminal 6.

Next, the operation will be described. When the positive sync signal and the negative sync signal are input from the input terminals 5 and 6, since the pull-down resistors 29 and 30 are set to high resistance values, the positive sync signal and the negative sync signal input to the NOR circuit 21 are input. The level of the negative sync signal is applied to the NOR circuit 21 as it is. Therefore, as described previously, the NOR circuit 2
The output signal of 1 is always at "L" level. Switch 12
Is switched to the L terminal side in response to this "L" level switching signal, the output signal of the attenuator 11 is selected and supplied to the R signal processing block 15.

Although not shown, the single-phase signal source 18
, The positive sync signal and the negative sync signal are not input to the input terminals 5 and 6, the two input terminals of the NOR circuit 21 are both at the “L” level, and the output signal thereof is “ It becomes H "level. Therefore, the switch 12 switches to the H terminal side in response to this "H" level switching signal, and the analog R signal input from the input terminal 7 is supplied to the R signal processing block 15.

According to the fourth embodiment, the positive / negative balanced signal source 2
When the output signal of 1 is input to the signal processing device 1, the input signal is automatically selected and supplied to the R signal processing block 15 of the next stage without any operation such as signal selection by the user. When the output signal of the single-phase signal source 18 is input to the signal processing device 1, this input signal is automatically selected and supplied to the R signal processing block 15 at the next stage.

Example 5. FIG. 6 is a circuit diagram showing a fifth embodiment of the present invention, showing a case where a single-phase signal source 18 is connected. In the figure, the same reference numerals as those in FIG. 3 indicate the same or corresponding portions, and 31 is an H level setting circuit, which connects the input terminal 5 to the “H” level power source through the pull-up resistor 32, and The input terminal 6 is connected to the “H” level power source through the pull-up resistor 33.

Next, the operation will be described. When the single-phase signal source 18 is connected, the positive sync signal and the negative sync signal are not input to the input terminals 5 and 6, so that the two input terminals of the AND circuit 23 are both at the “H” level, The output signal is always at "H" level. The switch 12 receives the "H" level switching signal and switches to the H terminal side, and the analog R signal input from the input terminal 7 is supplied to the R signal processing block 15.

Although not shown, when the positive / negative balanced signal source 2 is connected, the positive sync signal and the negative sync signal are input to the input terminals 5 and 6, so that the AND circuit 23 is connected. When one of the two input terminals is at "L" level, the other is at "H" level, so that the output signal of the AND circuit 23 is always at "L" level. The switch 12 switches to the L terminal side in response to this "L" level switching signal, the output signal of the attenuator 11 is supplied to the R signal processing block 15, and at the same time, the synchronization signal necessary for processing this signal is also supplied. It is supplied from the second subtractor 10 to the synchronization signal processing block 16.

According to the fifth embodiment, when the output signal of the single-phase signal source 18 is input to the signal processing device 1, this input signal is automatically selected without any operation such as signal selection by the user. And is supplied to the synchronization signal processing block 15 in the next stage. When the output signal of the positive / negative balanced signal source 2 is input to the signal processing device 1, a signal obtained by subjecting the input signal to a predetermined process is automatically selected and supplied to the R signal processing block 15 in the next stage. .

Example 6. FIG. 7 is a circuit diagram showing a sixth embodiment of the present invention, showing a case where a positive / negative balanced signal source 2 is connected. In the figure, the same reference numerals as those in FIG. 5 indicate the same or corresponding portions. In the sixth embodiment, the input terminal 3 is also used as an input terminal for a positive digital R signal and an analog R signal.

Next, the operation will be described. Positive / negative balanced signal source 2
Is connected, the positive sync signal and the negative sync signal are input from the input terminals 5 and 6. Therefore, when one of the two input terminals of the NOR circuit 21 is at the “L” level, the other is Since it is at "H" level, the output signal of the NOR circuit 21 is always at "L" level. The switch 12 is switched to the L terminal side in response to this "L" level switching signal, the output signal of the attenuator 11 is supplied to the R signal processing block 15, and at the same time, the synchronization signal necessary for processing this signal is also synchronized. It is supplied to the signal processing block 16.

FIG. 8 shows the signal processing apparatus 1 according to the sixth embodiment.
2 shows the case where the single-phase signal source 18 is connected. In this case, since the positive sync signal and the negative sync signal are not input from the input terminals 5 and 6, the two input terminals of the NOR circuit 21 are both at the "L" level and the output signal thereof is at the "H" level. . Therefore, the switch 12 switches to the H terminal side in response to the "H" level switching signal, and the analog R signal input from the input terminal 3 is supplied to the R signal processing block 15.

According to the sixth embodiment, the positive / negative balanced signal source 2
When the output signal of is input to the signal processing device 1, even if the input signal is not operated by the user such as signal selection,
When it is automatically selected and supplied to the R signal processing block 15 of the next stage and the output signal of the single-phase signal source 18 is input to the signal processing device 1, this input signal does not require an operation such as signal selection by the user. Is also automatically selected and supplied to the synchronization signal processing block 15 in the next stage.

In the sixth embodiment, the positive digital R
Although the signal input terminal is also used as the analog R signal input terminal, the negative digital R signal input terminal may also be used as the analog R signal input terminal.

Further, in each of the above embodiments, the output signals of the positive and negative balanced signal sources are the positive polarity digital R signal and the negative polarity digital R signal of the same phase, and the synchronization signal is the positive polarity synchronization signal and the negative polarity of the same phase. However, the present invention is not limited to this example.

In each of the above embodiments, the output signal of the single-phase signal source is the analog R signal, but the output signal is not limited to this example.

Further, in each of the above embodiments, the logic circuit for generating the switching signal of the switch from the positive digital R signal and the negative digital R signal is constituted by the NOR circuit or the AND circuit. However, the present invention is not limited to this. It is not something that can be done.

Further, in each of the above-mentioned embodiments, when the switching signal of the switch is at the "L" level, the "L" terminal side,
When the signal is at the "H" level, it is switched to the "H" terminal side, but it may be reversed.

[0047]

According to the present invention, when a signal such as a positive / negative balanced signal and a positive / negative balanced synchronizing signal is input from the first signal source, this signal is processed, and a single phase signal or the like is processed. Two
When a signal is input from the signal source, the signal is processed, so that there is an effect that a signal processing device that does not require a switching operation by the user can be obtained.

Further, it is possible to eliminate the input terminal of the second signal source for the single phase signal of the signal processing device.

Further, since the input terminal of the logic circuit is fixed to the L level or the H level by the level setting means and the input signal is selected by controlling the switch by the logic signal, the signal which does not require the switching operation by the user. The processing device can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing another connection example of the first embodiment.

FIG. 3 is a circuit diagram of a second embodiment of the present invention.

FIG. 4 is a circuit diagram of Embodiment 3 of the present invention.

FIG. 5 is a circuit diagram of Embodiment 4 of the present invention.

FIG. 6 is a circuit diagram of a fifth embodiment of the present invention.

FIG. 7 is a circuit diagram of Embodiment 6 of the present invention.

FIG. 8 is a circuit diagram showing another connection example of the sixth embodiment of the present invention.

FIG. 9 is a circuit diagram of a conventional signal processing device.

FIG. 10 is a circuit diagram showing another connection example of the conventional signal processing device.

[Explanation of symbols]

 1 signal processing device 2 positive / negative balanced signal source 3 positive polarity signal input terminal 4 negative polarity signal input terminal 5 positive polarity synchronization signal input terminal 6 negative polarity synchronization signal input terminal 7 single-phase signal input terminal 8 positive / negative balanced signal Processing block 9 First subtractor 10 Second subtractor 11 Attenuator 12 Switch 14 Signal switching circuit 15 R Signal processing block 16 Synchronous signal processing block 18 Single-phase signal source 21 Logical sum negation circuit (NOR circuit) 22 L level Setting circuit 23 AND circuit 24 H level setting circuit 25 Connector 26 L level setting circuit 27 Ground terminal 28 L level setting circuit 29 Pull down resistor 30 Pull down resistor 31 H level setting circuit 32 Pull up resistor 33 Pull Up resistor

Claims (7)

[Claims] 1. A common signal processing circuit for selecting this input signal when a signal is input from a first signal source and selecting this input signal when a signal is input from a second signal source. And a logic circuit whose output is controlled by the presence or absence of an input signal from the first or second signal source, and an output signal of the logic circuit. A signal processing device comprising: 2. When the positive / negative balanced signal forming the first signal source is input via the first subtractor, this input signal is selected and the single-phase signal forming the second signal source is input. Input signal switching circuit for selecting this input signal and transmitting it to a common signal processing circuit, and synchronization for inputting the positive / negative balanced synchronizing signal constituting the first signal source through the second subtractor. The input signal switching circuit is provided with a signal processing block, the input / output switching circuit is a logic circuit to which the positive / negative balanced synchronizing signal is input, and the positive / negative balanced synchronization signal is controlled by the output signal of the logic circuit. Select the signal,
A signal processing device comprising a switch that selects the single-phase signal when the positive / negative balanced synchronization signal is not input. 3. The signal processing apparatus according to claim 1, wherein the input terminal of the first signal source and the input terminal of the second signal source are shared. 4. A level setting means for fixing an input terminal of a logic circuit to an L level or an H level when a signal is not inputted from the first signal source, according to any one of claims 1 to 3. The signal processing device according to any one of claims. 5. The signal processing device according to claim 4, wherein the level setting means is a ground circuit for grounding an input terminal of the logic circuit or a grounded pull-down resistor. 6. The signal processing device according to claim 5, wherein the grounding circuit is configured to be grounded via a connection terminal of a connector provided on the second signal source side. 7. The signal processing device according to claim 4, wherein the level setting means is a circuit for connecting an input terminal of the logic circuit to a power supply of H level or a pull-up resistor connected to a power supply of H level.