JP3945181B2 - Video display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a video display device such as a television or a display having a D terminal which is an input terminal for an analog component video signal.
[0002]
[Prior art]
The video signal output terminal of a video playback device that outputs an analog component video signal, such as a digital tuner or a video disc player, is connected to the Japan Electronic Machinery Manufacturers Standard EIAJ CP-4120 “D terminal connection between digital tuner and television receiver” ( There are a mode of outputting from a D terminal defined by EIAJ CP-4120) and a mode of outputting 1 luminance signal system and 2 color difference signals from 3 independent terminals.
[0003]
When these two forms of output from the video playback device are input to the D terminal of the video display device, the output from the D terminal is connected by the D terminal cable, but the output from the three independent terminals is Then, it is converted into the D terminal specification in a pseudo manner by the conversion cable and inputted to the D terminal of the video display device.
[0004]
When a signal is input from the video playback device to the D terminal of the video display device, in the signal output from the former D terminal, in accordance with EIAJ CP-4120, three identification signal lines (line 1, line 2) of the D terminal are used. , Line 3) by reading the identification signal (DC voltage value), it can be determined whether the video format of the input signal is 525i, 525p, 1125i, 750p, or 1125p. Here, i indicates interlaced scanning, and p indicates sequential scanning. This discrimination method is hereinafter referred to as an identification signal discrimination method.
[0005]
FIG. 7 shows a criterion for determining the video format based on the DC voltage value of the identification signal line defined in Table 5 of EIAJ CP-4120. FIG. 8 shows the display of the D terminal defined in FIG. 7 of the standard. For example, in a video display device having a D terminal labeled D2, video signals of 525i and 525p video formats can be supported, that is, displayed.
[0006]
On the other hand, the signal output from the terminal that outputs the luminance signal and the color difference signal from three independent terminals is converted into the D terminal specification in a pseudo manner by the conversion cable. No identification signal is transmitted. Therefore, it is impossible to determine the video format based on the identification signal. Therefore, in this case, a method of discriminating the video format by extracting a synchronization signal from the video signal input to the D terminal and measuring the number (signal frequency) is common. This discrimination method is hereinafter referred to as a frequency discrimination method.
[0007]
In contrast to the video playback apparatus having these two types of output terminal forms, the video display apparatus having the D terminal does not use a method of discriminating the video format by the identification signal so that both output forms can be supported. In most cases, only the frequency discrimination method for discriminating the video format based on the frequency of the video signal is employed.
[0008]
[Problems to be solved by the invention]
A video display device that employs only the frequency discrimination method for discriminating the video format according to the frequency of the video signal has the advantage that it can easily be applied to a video playback device having two types of output terminal configurations. However, this method requires processing time of the process of extracting the synchronization signal from the video signal and measuring the frequency. Therefore, compared with the identification signal discrimination method (determination of only the DC voltage value) that discriminates the video format from the identification signal. , There is a drawback that it takes a long time to discriminate.
[0009]
Accordingly, in the case of a form in which one luminance signal system and two color difference signals are output from three independent terminals, the frequency discrimination method may be used, but in the case where the video reproduction apparatus is output from the D terminal, identification is performed. It can be said that the identification signal discrimination method for discriminating the video format based on the signal is superior.
[0010]
For example, when the input video format is switched, a normal video display device does not display abnormal video such as noise in the signal processing circuit that occurs during video format discrimination. It is almost to give. Here, in the conventional method, it is necessary to perform video non-display (MUTE) processing at least during the process of extracting the synchronization signal from the video signal and measuring the frequency. On the other hand, in the case of a signal input from a video playback device equipped with a D terminal output, if a method for discriminating the video format from the identification signal is adopted, the discriminating time of the video format can be instantaneously made, and the video is not displayed. (MUTE) Time can be shortened. In a general video display device, the shorter the video non-display (MUTE) time is, the better.
[0011]
An object of the present invention is to solve the above-described problems in a video display device having a frequency discrimination method and an identification signal discrimination method, and when the video signal is input from the D terminal of the video reproduction device, the identification signal An object of the present invention is to provide a video display device that uses a discrimination method to shorten the discrimination time.
[0012]
[Means for Solving the Problems]
To solve the problems described above, the present invention includes a plurality of a terminal analog component video signal from the video playback device is supplied, and an identification signal for identifying the video format of the video signal is input In a video display device having a D terminal having a plurality of identification signal lines , a voltage source having a predetermined voltage and a voltage from the voltage source are connected to at least one predetermined line of the plurality of identification signal lines via a resistor. Voltage application means to be applied, identification signal detection means for measuring the voltage value of the line to which the voltage is applied, and detecting the presence or absence of transmission of the identification signal based on the measurement value, and input to the plurality of identification signal lines based on the identification signals, a first format discrimination means for discriminating the image format of said image signal inputted through the D terminal, movies said input Counting the synchronizing signal of the signals, and a second format discriminating means for discriminating the image format of the image signal based on the regimen numbers, and the D terminal, as it said analog component video signal, the video Any one of the first component video signal output from the D terminal of the playback device and the second component video signal obtained by converting the luminance signal of the video playback device and the two color difference signals into the D terminal specification can be input. The identification signal detection means determines whether the analog component video signal supplied to the D terminal is the first component video signal or the second component video signal based on the measured voltage value. , if the identification signal detecting means determines that the in the D terminal first component video signal is input, the Using the first determination result from the first format discrimination means determines the image format of the input video signal, the case where the the D terminal the second component video signal is determined to have been input, the second using the second determination result from the format discrimination means, characterized by being configured to determine a video format of the input video signal.
[0013]
The identification signal line of the D terminal is for identifying the first identification signal line to which the first identification signal for identifying the number of scanning lines of the analog component video signal is input and the scanning format of the analog component video signal. A second identification signal line to which the second identification signal is input, and the identification signal detection means detects that the voltage values detected from the first identification signal line and the second identification signal line are both H. In the case of the level, it may be determined that the second component video signal is input to the D terminal. Furthermore, when the voltage value detected from the second identification signal line is a predetermined intermediate level, it may be determined that the second component video signal is input to the D terminal.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
First, the structure of the main functional block of the D terminal input circuit according to the present invention will be described. FIG. 1 is a block diagram showing an embodiment of the present invention, and shows a configuration corresponding to D1 video input, D2 video input, D3 video input, and D4 video input defined in EIAJ CP-4120. It is. As shown in the figure, in the D terminal input circuit 16, a voltage is applied to the identification signal line 1 and the signal identification line 2 of the D terminal 11 from the voltage source 12 through the resistors 13 and 14. The identification signal line to which this voltage is applied is input to the DC voltage determination circuit 15.
[0016]
Here, the operation of the DC voltage determination circuit 15 will be described with reference to FIG. In FIG. 2, L indicates a voltage value of 0 V, H indicates a voltage value of 5 V, and M indicates a voltage value of 2.2 V, and the DC voltage determination circuit 15 is a circuit that can detect within a reasonable range for each voltage value. The DC voltage determination circuit 15 outputs H when the identification signal line 1 and the identification signal line 2 are both H, and outputs L otherwise. Since such a circuit can be constituted by a known simple logic circuit, it will not be described in detail.
[0017]
At this time, in the present embodiment, D5 video input is not supported, that is, 1125p is not supported, so that identification signal line 1 and identification signal line 2 are both H from the table shown in FIG. There is no. Therefore, as shown in FIG. 1, by setting the voltage value of the voltage source 12 to 5 V, in the case of a pseudo D terminal specification in which nothing is connected to the identification signal line 1 and the identification signal line 2, the identification signal line 1 and the identification signal Both lines 2 become 5V, and the output of the DC voltage determination circuit 15 becomes H. In the case of the D terminal in which the identification signal from the video reproduction apparatus is input to the identification signal line 1 and the identification signal line 2, the output of the DC voltage determination circuit 15 is L unless both the identification signals are 5V. .
[0018]
As described above, in any of the D1 video input, the D2 video input, the D3 video input, and the D4 video input, the identification signal line 1 and the identification signal line 2 are both 5 V, as is apparent from FIGS. Therefore, when the output of the DC voltage determination circuit 15 is H, it can be determined that the pseudo D terminal specification has nothing connected to the identification signal line 1 and the identification signal line 2. That is, when the output of the DC voltage determination circuit 15 is H, nothing is connected to the identification signal line, so that the transmission video signal is output to the D terminal 11 from three independent terminals as a luminance signal and a color difference signal. It can be determined that the received signal is a processed signal. On the other hand, when the output of the DC voltage determination circuit 15 is L, since the identification signal (DC voltage) exists in the identification signal line, the video signal supplied to the D terminal 11 is a video signal output from the D terminal. Can be determined.
[0019]
FIG. 3 is a block diagram showing an embodiment of a video display apparatus incorporating the D terminal input circuit 16 of FIG. 3 includes a D terminal 11, a D terminal input circuit 16, a discrimination signal determination circuit 20, a control circuit 25, a synchronization separation circuit 21, a counter 22, a synchronization signal determination circuit 23, and a signal processing circuit 24 shown in FIG. The video display unit 26 is configured. In FIG. 3, output 2 is a determination result output from the identification signal determination circuit 20 to the control circuit 20. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals.
[0020]
This video display device includes a signal processing circuit 24 (for example, a scanning line interpolation circuit, a video enlargement / reduction circuit, etc.) in order to display an input video signal having a plurality of types of video formats on the video display unit 26. The control circuit 25 controls switching of the signal processing method according to the video format. In order for the control circuit 25 to switch the signal processing method of the signal processing circuit 24, it is necessary to first determine the video format of the input video signal. On the other hand, the video display device of FIG. 3 has two types of determination methods.
[0021]
One of the discriminating methods is that the sync signal is separated and extracted from the video signal inputted to the D terminal 11 by the sync separator circuit 21, and the sync signal discriminating circuit 23 is based on the number of sync signals (signal frequency) measured by the counter 22. Is a frequency discrimination method for discriminating the video format, and the discrimination result is output to the control circuit 25.
[0022]
Another method is an identification signal discrimination method in which a DC voltage value, which is an identification signal of the identification signal lines 1 to 3 input to the D terminal 11, is read by the identification signal discrimination circuit 20 to discriminate the video format. The determination result is output to the control circuit 25.
[0023]
In the video display device of FIG. 3, the output voltage of the D terminal input circuit 16 is used as means for selectively using these two types of discrimination methods. When the output 1 of the D terminal input circuit 16 is L, the discrimination signal discrimination method is used, the discrimination signal discrimination circuit 20 discriminates the video format of the input signal, and the control circuit 25 determines the signal processing circuit 24 based on the discrimination result. Switch the signal processing method. When the output 1 of the D terminal input circuit 16 is H, the frequency discrimination method is used, the video signal format of the input signal is discriminated by the sync signal discriminating circuit 23, and the signal processing of the signal processing circuit 24 is performed based on the discrimination result. Switch the method. By determining the video format, the signal processing method can be switched for the shortest time for each of the video signal output from the D terminal and the video signal output from the three independent terminals for the luminance signal and the color difference signal. Can be done.
[0024]
4 shows that in the video display device of FIG. 3, the identification signal lines 1 and 2 are both a D terminal input circuit 16 for determining the form of the input video signal and an identification signal determination circuit 20 for determining the video format of the input video signal. This is an example in which this is also used by one identification signal discriminating circuit 27. 4, parts that are the same as those in FIG. 3 are given the same reference numerals, and explanation thereof is omitted. The output 2 of the identification signal discriminating circuit 27 is the same as the output 2 of the identification signal discriminating circuit 20 shown in FIG. 3, and the DC voltages of the identification signals 1 to 3 are detected within an appropriate range. When the input is H, the voltage M is output when the input is L, and the voltage L is output when the input is L. The output 1 is the same as the output 1 of the D terminal input circuit 16 of FIG. 3, and is the output shown in FIG. As described above, the present embodiment has an advantage that it can cope with the conventional identification signal determination circuit with a small additional component.
[0025]
FIG. 5 is an example showing a configuration corresponding to D5 video input in addition to D1 video input, D2 video input, D3 video input, D4 video input corresponding to the D terminal input circuit of FIG. Thus, in the video signal output from the D terminal, the fact that the identification signal line 2 can take only DC voltages of H (5 V) and L (0 V) is used. In the example of FIG. 5, the voltage from the voltage source 32 is divided by resistors 33 and 34 and applied to the signal identification line 2 of the D terminal 11. Here, the voltage value of the voltage source 32 and the resistors 33 and 34 are set so that the voltage of the signal identification line 2 when nothing is connected to the D terminal 11 is about 2.2 V determined as M by the DC voltage determination circuit. Determine the resistance value. Similar to the D terminal input circuit of FIG. 1, an identification signal line is input to the DC voltage determination circuit 35. The DC voltage determination circuit 35 performs output processing as shown in FIG. 6 in accordance with each voltage. In FIG. 6, as in FIG. 2, L indicates a voltage value of 0V, H indicates a voltage of 5V, and M indicates a voltage value of 2.2V, but the DC voltage determination circuit 35 is a circuit that can detect each within an appropriate range. Here, in the case of the pseudo D terminal specification in which nothing is connected to the identification signal line 2, the identification signal line 2 becomes 2.2 V, and the output of the DC voltage determination circuit 35 becomes H. In the case of an output video signal from the D terminal to which the identification signal from the video reproduction apparatus is transmitted to the identification signal line 2, the output of the DC voltage determination circuit 35 is L regardless of whether the identification signal is 0V or 5V. . In any of the D1 video input, the D2 video input, the D3 video input, the D4 video input, and the D5 video input, the identification signal line 2 does not become 2.2 V. Therefore, when the output is H, the identification signal line 2 It can be determined that nothing is connected.
[0026]
If the D terminal input circuit 36 of FIG. 5 is incorporated in the video display device of FIG. 3 instead of the D terminal input circuit 16, in addition to the D1 video input, D2 video input, D3 video input, and D4 video input, the D5 video It can handle up to input.
[0027]
In the above embodiment, the case where the voltage value applied to the identification signal line via the resistor is 5 V of H or 2.2 V of M has been described. However, the present invention is not limited to this, and the identification signal is not limited to this. The present invention can also be applied when a DC voltage value used as is applied to at least one of the identification signal lines via a resistor. For example, in the EIAJ CP-4120, since H is in the range of 3.5 to 5V and M is in the range of 1.4 to 2.4V, the applied voltage value is about 1.0V or about 3.0V. It is also possible to detect the presence or absence of an identification signal.
[0028]
【The invention's effect】
According to the present invention, it is easy to discriminate whether the video signal supplied to the D terminal is an analog component video signal from the D terminal or an analog component video signal output from three terminals that are independent of the luminance signal and the color difference signal. it can. Based on the determination result, in the case of the video signal output from the D terminal, the video format can be determined instantaneously, and the minimum time is required for switching between the two types of output signals. The signal processing method can be switched with.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a D terminal input circuit of the present invention.
FIG. 2 is a table for explaining the operation of the DC voltage determination circuit of the D terminal input circuit shown in FIG.
FIG. 3 is a block diagram showing an embodiment of a video display device of the present invention incorporating the D terminal input circuit shown in FIG. 1;
FIG. 4 is a block diagram showing another embodiment of the video display device of the present invention.
FIG. 5 is a block diagram showing another embodiment of the D terminal input circuit of the present invention.
6 is a table for explaining the operation of the DC voltage determination circuit of the D terminal input circuit shown in FIG. 5;
FIG. 7 is a table showing video format discrimination criteria based on a DC voltage value of an identification signal line of a D terminal.
FIG. 8 is a table showing display rules for a D terminal.
[Explanation of symbols]
11 ... D terminal, 12, 32 ... voltage source, 13, 14, 33, 34 ... resistor, 15, 35 ... DC voltage judgment circuit, 16, 36 ... D terminal input circuit, 20, 27 ... identification signal discrimination circuit, 21 ... Sync separation circuit, 22 ... Counter, 23 ... Synchronization signal discriminating circuit, 24 ... Signal processing circuit, 25 ... Control circuit, 26 ... Video display section.

Claims (4)

A terminal is an analog component video signal from the video reproduction device is supplied, and a video display having a D terminal having a plurality of identification signal lines which identification signals for identifying the video format of the video signal is input in the device,
A voltage source having a predetermined voltage;
Voltage applying means for applying a voltage from the voltage source to at least a predetermined one of the plurality of identification signal lines via a resistor;
An identification signal detecting means for measuring a voltage value of the line to which the voltage is applied and detecting the presence or absence of transmission of the identification signal based on the measurement value;
Based on the identification signal inputted to the plurality of identification signal lines, and a first format discrimination means for discriminating the image format of said image signal inputted through the D terminal,
Second format discrimination means for counting a synchronization signal of the input video signal and discriminating a video format of the video signal based on the count value;
The D terminal converts the first component video signal output from the D terminal of the video playback device, the luminance signal of the video playback device, and two color difference signals into the D terminal specification as the analog component video signal. Any of the second component video signals can be input,
The identification signal detection means determines whether the analog component video signal supplied to the D terminal is the first or second component video signal based on the measured voltage value.
When the identification signal detection means determines that the first component video signal is input to the D terminal, the first video signal is input using the first determination result from the first format determination means . When the video format is determined and it is determined that the second component video signal is input to the D terminal, the video of the input video signal is used using the second determination result from the second format determination means. A video display device configured to determine a format. The video display device according to claim 1, further comprising a control circuit and a signal processing circuit that performs signal processing on the first or second component video signal.
When the first video signal is input to the D terminal, the control circuit performs video signal processing corresponding to the video format determined by the first format determination unit, in the first component video signal. Controlling the signal processing circuit to
When the second component video signal is input to the D terminal, the video signal processing corresponding to the video format determined by the second format determination unit is performed on the second component video signal. A video display device, wherein the signal processing circuit is controlled to perform. 3. The video display device according to claim 1, wherein the identification signal line of the D terminal is a first identification signal line to which a first identification signal for identifying the number of scanning lines of the analog component video signal is input. A second identification signal line to which a second identification signal for identifying a scanning format of the analog component video signal is input,
When the voltage values detected from the first identification signal line and the second identification signal line are both at the H level, the identification signal detection means receives the second component video signal to the D terminal. A video display device characterized in that it is determined to be present. 3. The video display device according to claim 1, wherein the identification signal line of the D terminal includes an identification signal line to which an identification signal for identifying a scanning format of the analog component video signal is input.
The identification signal detecting means has a voltage value detected from the identification signal line having a predetermined intermediate level. In the case of a video display device, it is determined that the second component video signal is input to the D terminal.

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