JPH07298209A - Television receiver - Google Patents

Abstract

PURPOSE:To allow the television receiver to surely discriminate a broadcast system and to set an optimum mode depending on the broadcast system. CONSTITUTION:A base band video signal is separated into a luminance signal and a chrominance signal by a Y/C separator and color demodulation circuit 2. A signal identification circuit 4 uses an identification signal for a 2nd generation EDTV signal to discriminate whether the base band video signal is an NTSC system signal or a signal of the 2nd generation EDTV signal when the base band video signal is a standard signal. Furthermore, the signal identification circuit 4 discriminates whether the base band video signal is an NTSC system signal or a signal of the 2nd generation EDTV signal based on whether or not a non-picture part is in existence in the video signal when the base band video signal is a non-standard signal. Thus, even when the identification signal for the non-standard signal is subjected to distortion, the broadcast system is precisely identified.

Description

Detailed Description of the Invention

[Object of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver suitable as a monitor of a reproduced signal from a VTR.

[0002]

2. Description of the Related Art In recent years, second-generation EDTV (Extended Definition TV) broadcasting aimed at high image quality and high sound quality has been studied. Second-generation EDTV broadcasting is compatible with current broadcasting and has a screen aspect ratio of 1
The horizontal aspect ratio of 6: 9 makes it possible to watch programs with a realistic feel. The effective scanning line of the second generation EDTV signal corresponds to the vertical center 16: 9 portion of the current NTSC signal having an aspect ratio of 4: 3. Therefore, for example, when a second-generation EDTV broadcast is projected by a television receiver for current broadcasting having an aspect ratio of 4: 3,
A letterbox display having a non-image portion at the top and bottom of the screen is performed. In Europe, wide aspect broadcasting called PAL plus is under study.

The second generation EDTV has an aspect ratio of 4:
Since only the central 16: 9 portion of the current NTSC signal of No. 3 is the effective scanning line, the number of effective scanning lines of the current NTSC signal is 480, whereas the second generation ED for transmission
The number of effective scanning lines for TV signals is 360. At the time of decoding, these 360 effective scanning lines are converted into 3 → 4 scans to obtain 4
Return to 80. Since the vertical resolution of the second-generation EDTV signal deteriorates as compared with the current NTSC signal if only the scan line conversion is performed, it is decided to multiplex and transmit the vertical reinforcement signal for improving the vertical resolution at the time of transmission. ing.

At the beginning of broadcasting, the signal has an aspect ratio of 1 with the signal of the current NTSC system with an aspect ratio of 4: 3.
It is expected that a 6: 9 second-generation EDTV system signal will be mixed and broadcast for each program. Therefore, it is necessary for the receiving side to perform control corresponding to the current NTSC system and the second-generation EDTV system, respectively. Therefore, it is also decided on the transmitting side to multiplex and transmit an identification signal indicating that the second generation EDTV system broadcast signal is being transmitted. The identification signal indicates the aspect ratio of the broadcast signal and the presence / absence of various reinforcing signals. By detecting the identification signal, it is determined whether or not the second generation EDTV system broadcast signal is received, and the identification result is used to perform control corresponding to each broadcast system.

For example, the screen mode is set based on the identification result of the identification signal. If the aspect ratio of the display screen of the receiver is 16: 9, the second
When it is detected that a signal of the next generation EDTV system is received, the vertical amplitude is enlarged and a wide aspect image is displayed on the entire screen. In this case, the wide-aspect image may be displayed on the entire screen after the resolution is improved by using the reinforcement signal, instead of simply increasing the vertical amplitude. On the other hand, when the aspect ratio of the receiver is 4: 3, when the identification signal indicates that the signal of the second generation EDTV system is received, the upper and lower non-image portions are masked. As a result, it is possible to prevent flicker due to the reinforcement signal superimposed on the non-image portion.

FIG. 9 is an explanatory diagram showing this identification signal.

The identification signal is at the top of the image area (22H,
285H) in the horizontal scanning period. The identification signal is
As shown in FIG. 9, it has bit areas B1 to B27 for 27 bits. The bit width of each bit is 7 times the color subcarrier period. Bit areas B1 to B5 are identification codes S1 transmitted in the NRZ (non-return zero) format, and bit areas B6 to B23 are identification codes S2 (color subcarrier frequency fsc) in the color subcarrier format. Further, the bit areas B25 to B27 are confirmation signals S3 for determining the existing video signal. The confirmation signal S3 has a frequency of 2.0
It is a sine wave of 4 MHz (= (4/7) fsc). In addition,
Information about the aspect ratio is transmitted by the identification code S1 of the bit areas B3 and B4.

By the way, it is conceivable to record or reproduce the second generation EDTV broadcast signal in a home VTR. However, in a domestic VTR, a recording signal is processed using a comb filter. This processing causes crosstalk in signals between the scanning lines. The identification signals are 22H and 285 as described above.
Since it is multiplexed with H, and processed by a comb filter, the amplitude component changes due to the signals of the preceding and following lines. As a result, the NRZ format identification code S1 is distorted, and it becomes impossible to correctly discriminate the information regarding the aspect ratio.

Further, during magnetic recording or reproduction,
The high frequency component of the luminance signal may be attenuated. In this case, the amplitude of the confirmation signal S3 having a frequency of 4/7 fsc is also attenuated. If the amplitude of the confirmation signal S3 in the reproduced signal is attenuated, the confirmation signal S3 may be erroneously discriminated as a video signal. Then, the television receiver displaying the reproduction signal determines that the identification signal is not multiplexed in 22H or 285H, and performs processing as a signal of the current system having an aspect ratio of 4: 3.

In particular, identification of aspect ratio information is important. For example, in a receiver having an aspect ratio of 4: 3, when a signal having an aspect ratio of 4: 3 is erroneously determined to be a letterbox signal, the upper and lower portions where an image is originally displayed are masked. On the contrary, if the letterbox signal is erroneously determined to be the current broadcast signal, the upper and lower parts of the screen flicker due to the reinforcement signals multiplexed in the upper and lower non-image parts. Also, the aspect ratio is 1
In the 6: 9 image receiver, there is a problem in that the non-image portion is displayed in the upper and lower portions of the screen and the screen cannot be used effectively.

Even in the PAL plus signal, the identification signal is transmitted in a predetermined one line of one frame. Therefore, the identification signal of the PAL plus signal is also the home VT
Waveform distortion occurs when recording or reproducing R.

[0012]

As described above, the waveform of the identification signal included in the reproduced signal from the home-use VTR may be distorted in the related art, and in the conventional television receiver, it is included in the identification signal. Information may be erroneously recognized, and the determination as to whether or not the identification signal is multiplexed may be erroneous. For this reason, there is a problem that the optimum mode for the system of the input video signal is not set.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a television receiver capable of discriminating the system of an input video signal.

Another object of the present invention is to provide a television receiver capable of setting an optimum mode according to the system of an input video signal.

[Constitution of Invention]

A television receiver according to the present invention performs predetermined signal processing on an input video signal based on a wide aspect television signal or a current television signal in which a predetermined identification signal is multiplexed. Video signal processing means to be supplied to the monitor and detecting whether the input video signal is a standard signal or a non-standard signal, and when the standard signal is detected, the identification signal is added to the input video signal. The input video signal system is determined based on whether or not the input video signal is multiplexed, and when it is detected that the input video signal is a non-standard signal, the input video signal is determined by whether or not the input video signal has a non-image portion. And a control means for controlling the display on the monitor based on the discrimination result.

[0016]

In the present invention, the standard signal or non-standard signal of the current television signal or the wide aspect television signal is input to the video signal processing means, the predetermined signal processing is performed, and the signal is supplied to the monitor. When the input video signal is a standard signal, the signal identifying means determines the broadcasting system by detecting the identification signal multiplexed with the wide aspect television signal. Also, the signal identification means is
When the input signal is a non-standard signal, the broadcasting system is determined based on whether or not the input video signal has a non-image portion, that is, whether or not it is a letterbox format signal, for example. As a result, even if the identification signal of the non-standard signal is distorted, the broadcasting system can be reliably determined. The control means controls the display on the monitor based on the result of discrimination of the broadcasting system.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a television receiver according to the present invention.

A baseband video signal is input to the input terminal 1. A baseband video signal received by a tuner (not shown) and demodulated may be input to the input terminal 1, or a baseband video signal reproduced from a VTR may be input. This baseband signal is a signal of the NTSC system or the second generation EDTV system. FIG. 2 is an explanatory diagram for explaining a broadcast signal of the second generation EDTV system.

As described above, in the second generation EDTV signal, the effective image (main screen signal) is transmitted in the portion (main screen portion) where the vertical aspect ratio of the NTSC video signal is 16: 9. It is transmitted in the letterbox format with the upper and lower parts as the non-image part. As shown in FIG. 2, the number of scanning lines of the non-image part 11 at the top and bottom of the screen is 60, and the number of scanning lines of the main screen part 12 at the center of the screen is 360. A vertical reinforcement signal for improving the vertical resolution is multiplexed in the non-image portion 11.

The baseband video signal input through the input terminal 1 is a Y / C separation and color demodulation circuit 2, a second generation E
It is supplied to the DTV processing circuit 3, the signal identification circuit 4, and the synchronization circuit 5. The Y / C separation and color demodulation circuit 2 separates the input baseband video signal into a luminance signal and a color signal, demodulates the separated color signal to obtain a color difference signal, and outputs the luminance signal and the color difference signal to R. , G, B signals. Y / C
The separation / color demodulation circuit 2 outputs the luminance signal and the color signal to the second generation EDTV processing circuit 3 and outputs the R, G, B signals to the selection circuit 6.

The second generation EDTV processing circuit 3 demodulates the vertical reinforcement signal superimposed on the non-image part of the baseband video signal from the input terminal 1. Second generation EDTV processing circuit 3
Adds the demodulated vertical reinforcement signal with the luminance signal from the Y / C separation and color demodulation circuit 2 to improve the resolution. Further, the second generation EDTV processing circuit 3 demodulates the color signal to obtain a color difference signal and performs scanning line conversion of the luminance signal and the color difference signal to thereby obtain the number of effective scanning lines of the main screen signal of the second generation EDTV system. To 480 lines. The second generation EDTV processing circuit 3 converts the luminance signal and the color difference signal into R, G, B signals and outputs them to the selection circuit 6. From the second generation EDTV processing circuit 3, the number of scanning lines is converted to 480 and a squeeze signal which is vertically extended is output. The synchronizing circuit 5 separates the horizontal and vertical synchronizing signals from the baseband video signal and outputs them to the horizontal deflection circuit 8 and the vertical deflection circuit 9, respectively.

When the input video signal is a signal conforming to the broadcasting standard (hereinafter referred to as a standard signal), the signal identifying circuit 4 detects whether or not the identifying signal is inserted in 22H or 285H. Thus, it is determined whether the input video signal is a signal of the current broadcasting system or a wide aspect signal of the second generation EDTV system. Further, when the input video signal is a non-standard signal such as a VTR reproduction signal, the signal identification circuit 4 determines whether or not the input video signal is a letterbox type signal having a non-image portion at the top and bottom of the screen. Determine. The signal identification circuit 4 controls the selection circuit 6, the horizontal deflection circuit 8 and the vertical deflection circuit 9 based on the determination result.

The selection circuit 6 selects the R, G, B signals from the Y / C separation and color demodulation circuit 2 or the second generation EDTV processing circuit 3 based on the discrimination result from the signal discrimination circuit 4 and sends them to the monitor 7. It is supposed to be supplied. The monitor 7 has its deflection controlled by the horizontal and vertical deflection circuits 8 and 9, and the selection circuit 6
An image based on the R, G, and B signals from is displayed on the display screen.

FIG. 3 is a block diagram showing a specific configuration of the signal identifying circuit 4 in FIG.

The baseband video signal from the input terminal 1 is given to the second generation EDTV identification circuit 21, the non-image part detection circuit 22 and the standard detection circuit 23. The second generation EDTV identification circuit 21 has one line for each field (22H, 285H)
To decode the identification signal transmitted. The second generation EDTV identification circuit 21 determines whether the video signal input based on the decoding result is an NTSC signal or not.
The determination result indicating whether the signal is a DTV system signal is determined by the determination circuit 24.
It is designed to output to.

The no-image-portion detection circuit 22 detects whether or not there is a black-level non-image portion in the upper and lower portions of the video signal in the vertical direction, and outputs the detection result to the discrimination circuit 24. The standard detection circuit 23 detects whether the video signal is a standard signal or a non-standard signal and outputs the detection result to the determination circuit 24.

If the detection result of the standard detection circuit 23 indicates that the input video signal is a standard signal, the discrimination circuit 24 detects the input video signal based on the discrimination result of the second generation EDTV discrimination circuit 21. When the system is judged and it is shown that the input video signal is a non-standard signal, the system of the input video signal is judged based on the detection result of the non-image part detection circuit 22. The discrimination circuit 24 is the second generation EDT.
When it is determined that the input video signal is a signal of the NTSC system according to the determination result of the V identification circuit 21 or the detection result of the non-image area detection circuit 22, the selection circuit 6 outputs the Y / C separation and color demodulation circuit 2 When the output is selected and it is determined that the signal is of the second generation EDTV system, the second generation E
A discrimination signal for selecting the output of the DTV processing circuit 3 is output. Further, the discrimination circuit 24 determines whether the input video signal is the NTSC system signal or the second generation ED.
A discrimination signal for controlling horizontal and vertical deflection of the screen is output based on whether the signal is a TV system signal.

FIG. 4 shows the second generation EDTV discriminating circuit in FIG.
FIG. 23 is a block diagram showing a specific configuration of 21.

The baseband video signal input via the terminal 31 of the second generation EDTV identification circuit 21 is supplied to the NRZ decoding circuit 32, the fsc modulation signal decoding circuit 33, the confirmation signal detection circuit 34 and the synchronization timing generation circuit 35. To be done. N
The RZ decoding circuit 32 decodes the NRZ format identification code transmitted in the bit areas B1 to B4 of the identification signal and outputs it to the shift register 36.

The fsc modulation signal decoding circuit 33 decodes the identification code of the color subcarrier frequency transmitted in the bit areas B6 to B23 of the identification signal. Bit area B6 to B23
The identification code of 1 transmits control information according to the boundary phase of each bit area or the phase of the confirmation signal. For example, if it is in phase with the color burst phase, it is determined that the identification code is "0", and if it is in antiphase, it is determined to be "1". That is, the identification result is obtained by the fsc modulation signal decoding circuit 33 demodulating the identification code transmitted in the color subcarrier format in the color burst phase. The output of the fsc modulation signal decoding circuit 33 is supplied to the shift register 36.

The shift register 36 is an NRZ decoding circuit 32.
And the output of the fsc modulation signal decoding circuit 33 is held and CR
Output to the C check circuit 37. Bit area B6 to B23
Among the identification codes, the signals in the bit areas B18 to B23 are error correction codes. This error correction code is intended for both the NRZ type identification code and the color subcarrier type identification code. The CRC check circuit 37 has bit areas B18 to B
The error of the identification code of NRZ format and the identification code of color subcarrier format is corrected by using the error correction code 23 and output to the determination circuit 38.

The confirmation signal detection circuit 34 detects whether or not the input baseband video signal includes a confirmation signal having a frequency of 4/7 fsc, and outputs the detection result to the determination circuit 38. The synchronization timing generation circuit 35 uses a clock CK necessary for various processes based on the input baseband video signal.
And a gate signal Tm necessary for extracting the identification signal is generated and output to the judgment circuit 38.

The decision circuit 38 takes in the outputs of the confirmation signal detection circuit 34 and the CRC check circuit 37 at the timing of the gate signal Tm. When the confirmation signal detection circuit 34 detects that the confirmation signal is included in the input video signal, the determination circuit 38 outputs the output of the CRC check circuit 37 as a determination output. On the other hand, when the confirmation signal detection circuit 34 detects that the confirmation signal is not included, the determination circuit 38 outputs 2 regardless of the output of the CRC check circuit 37.
It is determined that the 2H or 285H signal is not the identification signal but the video signal. That is, in this case, the input baseband video signal outputs a determination output indicating that it is an NTSC system signal.

In the second generation EDTV discriminating circuit 21 thus constructed, the confirmation signal detecting circuit 34 detects whether or not the confirmation signal is included in the input video signal. Since the confirmation signal is not included in the NTSC system video signal, when the confirmation signal is not detected by the confirmation signal detection circuit 34, the determination circuit 38 inputs the NTSC signal to the input terminal 1.
A determination output indicating that the system signal has been input is output.

On the other hand, when the signal of the second generation EDTV system is input to the input terminal 1, the decision circuit 38 outputs the output of the CRC check circuit 37 as the decision output. That is, the NRZ format identification code in the identification signal of the second generation EDTV signal is decoded by the NRZ decoding circuit 32, and the color subcarrier format identification code is decoded by the fsc modulation signal decoding circuit 33. These decoding results are supplied to the CRC check circuit 37 via the shift register 36 and subjected to error correction, and then output as a determination output via the determination circuit 38. This judgment output indicates that the input video signal is a letterbox format signal, the reinforcement signal is multiplexed, and the like.

FIG. 5 is a block diagram showing a specific configuration of the non-image part detection circuit 22 in FIG.

The non-image portion detection circuit 22 detects the presence or absence of the non-image portion for each scanning line in a predetermined area in the upper and lower portions of the screen. That is, the base band video signal includes a horizontal low-pass filter (hereinafter, horizontal LPF) 41, a horizontal band-pass filter (hereinafter, horizontal BPF) 42, and a vertical band-pass filter (hereinafter vertical BPF).
43) and the synchronization timing generation circuit 44.

The horizontal LPF 41 passes the horizontal low-frequency component of the baseband video signal and outputs it to the DC value detection circuit 45.
The horizontal LPF 41 extracts the luminance signal component of the baseband video signal. The DC value detection circuit 45 detects whether the output level of the horizontal LPF 41 is below a predetermined value. DC
The value detection circuit 45 outputs 0 to the judgment circuit 48 when the output level of the horizontal LPF 41 is below a predetermined value, and outputs a predetermined level output to the judgment circuit 48 when it exceeds the predetermined value. Horizontal B
The PF 42 has a color subcarrier band as a pass band, and extracts a carrier color signal component and a luminance signal horizontal high band component of the input baseband video signal and outputs them to the non-linear circuit 46.

FIG. 6 is a graph showing the input / output characteristics of the nonlinear circuit 46.

As shown in the graph of FIG. 6, the non-linear circuit 46 has an output of 0 when the level of the input signal is less than or equal to a predetermined value and an output of a predetermined level when the level of the input signal exceeds the predetermined value. ing. That is, the non-linear circuit 46 outputs a signal of a predetermined level to the determination circuit 48 when the level of the carrier color signal component of the baseband video signal or the level of the luminance signal horizontal high frequency component exceeds a predetermined value. .

In the second-generation EDTV signal, the amplitude of the vertical reinforcement signal superimposed on the non-image portion is set so that the flicker of the non-image portion displayed at the top and bottom of the display screen with the aspect ratio of 4: 3 is not noticeable. Limited. Therefore, when the input baseband video signal has a non-image part, the outputs of the DC value detection circuit 45 and the non-linear circuit 46 become 0, and when the signal in this period is a video signal, the DC value detection circuit. 45
The output of the non-linear circuit 46 is a signal of a predetermined level.

The vertical BPF 43 extracts the vertical high frequency component of the input baseband video signal. FIG. 7 is a block diagram showing a specific configuration of the vertical BPF 43 in FIG.

The vertical BPF 43 is composed of 1H delay circuits 61 and 62, coefficient units 63 to 65, and an adder 66. 1H
The delay circuit 61 delays the input baseband video signal by 1H and supplies it to the 1H delay circuit 62, and the 1H delay circuit 62 delays the input signal by 1H. That is, the input of the 1H delay circuit 61 and the outputs of the 1H delay circuits 61 and 62 are video signals of three consecutive lines (previous line, current line, next line) at the same horizontal position.

The coefficient unit 63 outputs the video signal of the previous line by -1/4.
Multiply and adder 66 output. The coefficient unit 64 multiplies the video signal of the current line by 1/2 and outputs it to the adder 66. The coefficient unit 65 multiplies the video signal of the next line by -1/4 and outputs it to the adder 66.
Since the color subcarriers are inverted around 1 line, and the video signals are correlated around 1 line, a predetermined 2
A signal in the color subcarrier band can be extracted by subtracting the video signal of the line. In this way, the vertical high frequency component of the baseband video signal is output from the adder 66.

The vertical high frequency component from the vertical BPF 43 is supplied to the non-linear circuit 47. The non-linear circuit 47 has the same configuration as the non-linear circuit 46, and the output is 0 when the level of the input signal is less than or equal to a predetermined value, and the output becomes the predetermined level when the level exceeds the predetermined value. That is, when the level of the vertical high frequency component of the baseband video signal exceeds a predetermined value from the non-linear circuit 46, the signal of the predetermined level is determined by the determination circuit.
It is designed to be output to 48. Since the non-image portion has no vertical high frequency component, the presence or absence of the non-image portion can be detected by the output of the non-linear circuit 46.

The synchronization timing generation circuit 44 generates a synchronization signal and a timing signal based on the input baseband signal and outputs them to the determination circuit 48. The determination circuit 48 outputs a detection result indicating whether or not the input baseband video signal is a letterbox format signal based on the outputs of the DC value detection circuit 45 and the nonlinear circuits 46 and 47.

In the non-image area detection circuit thus constructed, when a letterbox format signal is input,
In the upper and lower non-image parts, the outputs of the DC value detection circuit 45 and the non-linear circuits 46 and 47 both become predetermined levels. As a result, the determination circuit 48 outputs a detection result indicating that the letterbox format signal is input.

On the other hand, when the NTSC signal is input, DC
The outputs of the value detection circuit 45 and the nonlinear circuits 46 and 47 are both 0.
Becomes As a result, the determination circuit 48 outputs the detection result indicating that the NTSC system signal is input.

In the reproduction signal of the VTR, the DC offset of the non-image portion does not change, and the presence or absence of the upper and lower non-image portions can be surely detected by the non-image portion detecting circuit 22.

FIG. 8 is a block diagram showing a specific structure of the standard detection circuit 23 shown in FIG.

In the standard signal, the phase relationship between the color subcarrier and the vertical synchronizing signal VD is constant, and in the non-standard signal such as the VTR reproduction signal, the phase relationship between the color subcarrier and the vertical synchronizing signal VD is constant. It is indefinite. The standard detection circuit 23 is
The phase relationship between the color subcarrier and the vertical synchronizing signal VD is detected to detect whether the input baseband video signal is a standard signal or a nonstandard signal.

That is, the standard detection circuit 23 has a color subcarrier reproduction circuit and a sync separation circuit (not shown), and the horizontal sync signal HD is supplied to the timing generation circuit 53 and the latch 56. The vertical sync signal VD is input to the latch 56.
Also, the latch 56 latches the vertical synchronizing signal VD at the timing of the horizontal synchronizing signal HD, and the timing generating circuit 53.
Output to. The timing generating circuit 53 divides the output of the latch 56 by two and outputs it to the 910 frequency dividing circuit 51 as the reset signal VRST at the timing of the horizontal synchronizing signal HD.

On the other hand, the 910 frequency divider circuit 51 is also supplied with the quadruple-frequency signal 4fsc of the color subcarrier. 91
The divide-by-zero circuit 51 is reset by the reset signal VRST, divides the frequency-multiplied signal 4fsc by 910 and outputs it to the latch 52. That is, the 910 frequency divider circuit 51 is reset once per frame in synchronization with the horizontal synchronizing signal, and outputs a signal of horizontal frequency (fH) synchronized with the color subcarrier to the latch 52.

The timing generation circuit 53 uses the vertical synchronizing signal VD.
Is output to the latch 52 as a latch timing signal VR, and the latch 52 outputs the output of the frequency dividing circuit 51 to the timing signal V
It is latched at the timing of R and output to the comparison circuit 54. Two reference values are also input to the comparison circuit 54. Comparison circuit
54 detects whether the output of the latch 52 is a value between two reference values, and outputs the detection result to the continuity detection circuit 55.

When the phase of the color subcarrier and the phase of the vertical synchronizing signal VD always have a constant phase difference, the latch
The output of 52 becomes a constant level, and this level is compared
Can be set to a value between the two reference values supplied to the. The continuity detection circuit 55 uses the vertical synchronization signal V
D is also given, and it is detected whether the comparison result of the comparison circuit 54 is continuous in field units. The continuity detection circuit 55 outputs the detection result indicating that the standard signal is input when the comparison results are continuous, and the detection result indicating that the non-standard signal is input when the comparison results are not continuous. Is output.

In the standard detection circuit 23 thus constructed, the output of the 910 frequency divider circuit 51 becomes a horizontal frequency signal synchronized with the color subcarrier of the input baseband video signal. The latch 52 latches the output of the 910 frequency divider circuit 51 at a timing synchronized with the vertical synchronizing signal VD and compares the output with the comparison circuit 54.
Output to. The comparison circuit 54 compares whether the output of the latch 52 is a value between two predetermined reference values, for example, the latch 52.
If the output is a value between the two reference values, "1" is output to the continuity detection circuit 55, and if not, "0" is output to the continuity detection circuit 55.

Now, it is assumed that a baseband video signal obtained by tuning in a tuner (not shown) is input through the input terminal 1. In this case, since the phase relationship between the color subcarrier and the vertical synchronizing signal is constant, the output of the latch 52 is always at a constant level. Therefore, the comparison circuit 54 always outputs "1". The continuity detecting circuit 55 uses the vertical synchronizing signal VD to detect that the output of the comparing circuit 54 is continuous in field units. Thus, the continuity detection circuit
55 outputs a detection result indicating that the input baseband video signal is a standard signal.

On the other hand, it is assumed that a VTR reproduction signal is input through the input terminal 1. In this case, the phase relationship between the color subcarrier and the vertical sync signal is indefinite. Therefore, the output level of the latch 52 changes and the output of the comparison circuit 54 also changes. The continuity detection circuit 55 detects that the output of the comparison circuit 54 is not constant and outputs a detection result indicating that the input video signal is a non-standard signal.

Next, the operation of the embodiment thus constructed will be described.

A baseband video signal of the NTSC system or the second generation EDTV system is input to the input terminal 1. This baseband signal may be a video signal obtained by tuning with a tuner, or may be a VTR playback signal. The input baseband video signal is separated into a luminance signal and a color signal in the Y / C separation and color demodulation circuit 2, and the color signal is demodulated into a color difference signal. The Y / C separation and color demodulation circuit 2 converts the luminance signal and the color difference signal into R, G and B signals.
The signal is converted into a signal and output to the selection circuit 6.

The luminance signal and the color signal from the Y / C separation and color demodulation circuit 2 are given to the second generation EDTV processing circuit 3. The second generation EDTV processing circuit 3 decodes the reinforcement signal multiplexed in the non-image part of the baseband video signal to improve the resolution of the luminance signal. Second generation EDTV
The processing circuit 3 performs color demodulation of the color signal to obtain a color difference signal, and scan line conversion of the luminance signal and the color difference signal to obtain a squeeze signal of 480 lines / screen height. The second generation EDTV processing circuit 3 converts the luminance signal and the color difference signal into R, G, B signals and outputs them to the selection circuit 6.

Now, it is assumed that the NTSC baseband video signal selected by the tuner is input to the input terminal 1. Standard detection circuit of the signal identification circuit 4
When 23 (see FIG. 3) detects that the standard signal is input, it causes the determination circuit 24 to output the determination output of the second generation EDTV identification circuit 21. The confirmation signal detection circuit 34 (see FIG. 4) of the second generation EDTV identification circuit 21 detects whether or not the confirmation signal is included in the identification signal insertion period. In this case, since the confirmation signal is not included, the determination circuit 38
A determination output indicating that the SC system signal has been input is output.

Based on this judgment output, the selection circuit 6 outputs Y /
The output of the C separation and color demodulation circuit 2 is selected and supplied to the monitor 7. The determination output is also given to the horizontal deflection circuit 8 and the vertical deflection circuit 9. The aspect ratio of monitor 7 is 4:
If 3, the horizontal deflection circuit 8 and the vertical deflection circuit 9
Performs normal deflection processing. As a result, an NTSC broadcast image is displayed on the display screen of the monitor 7.

When the aspect ratio of the monitor 7 is 16: 9, the horizontal deflection circuit 8 increases the horizontal amplitude by 3/4 to display the NTSC image at the center of the screen in the horizontal direction. Note that the R, G, and B signals from the selection circuit 6 may be displayed after being compressed 3/4 times in the horizontal direction (time direction) without controlling the horizontal deflection.

Here, it is assumed that the tuner receives a signal of the second generation EDTV system. In this case, the confirmation signal detection circuit 34 of the second generation EDTV identification circuit 21 detects the confirmation signal during the identification signal insertion period. Then, the determination circuit 38 outputs the output of the CRC check circuit 37 as the determination output. The NRZ decoding circuit 32 and the fsc modulated signal decoding circuit 33 decode the NRZ format identification code and the color subcarrier format identification code, respectively. Decode result is CR
After the error is corrected by the C check circuit 37, it is output as a judgment output.

The judgment output indicates that the input video signal is a letterbox format signal and that the reinforcement signal is multiplexed in the non-image portion. Based on this determination output, the selection circuit 6 selects the output of the second generation EDTV processing circuit 3 and outputs it to the monitor 7. In this way, the squeeze signal from the selection circuit 7 is supplied to the monitor 7, and when the aspect ratio of the monitor 7 is 16: 9, only the effective image is displayed on the entire screen by the normal horizontal and vertical deflection processing.

When the aspect ratio of the monitor 7 is 4: 3, the monitor 7 displays the non-image portion after masking processing. This prevents the non-image part from flickering and makes it easier to see the image in the center of the screen.

Next, it is assumed that the VTR reproduction signal is input to the input terminal 1. In this case, even if the reproduction signal is the video signal of the second generation EDTV system, the identification signal may be unidentifiable due to distortion. The standard detection circuit 23 of the signal identification circuit 4 detects that the input video signal is a non-standard signal and outputs the detection result to the discrimination circuit 24. As a result, the discrimination circuit 24 selects the output of the non-image area detection circuit 22.

Here, it is assumed that the reproduction signal is an NTSC video signal. Then, the non-image area detection circuit 22
The outputs of the horizontal LPF 41, the horizontal BPF 42, and the vertical BPF 43 become relatively high levels, and the outputs of the DC value detection circuit 45 and the nonlinear circuits 46 and 47 become predetermined levels, and the determination circuit
Reference numeral 48 outputs a detection result indicating that an NTSC system signal has been input. This detection result is supplied to the selection circuit 6 via the discrimination circuit 24. The selection circuit 6 selects the output of the Y / C separation and color demodulation circuit 2 and outputs it to the monitor 7. Subsequent operations are the same as when the signal from the tuner is input.

Next, it is assumed that the reproduction signal is a video signal of the second generation EDTV system. In this case, the non-image portion detection circuit 22 outputs the detection result indicating that the non-image portion exists. The selection circuit 6 selects the output of the second generation EDTV processing circuit 3. The operation in this case is also the same as when the signal from the tuner is input.

As described above, in the present embodiment, the standard detection circuit of the signal identification circuit determines whether the input video signal is the standard signal or the non-standard signal, that is, the tuner is selected and obtained. Whether it is a video signal or a VTR reproduction signal is detected, if it is a standard signal, an identification signal is detected, and if it is a non-standard signal, the presence or absence of a non-image portion is detected. The identification signal of the non-standard signal of the second generation EDTV system may be distorted, and even if this identification signal is used, it is impossible to accurately determine the broadcasting system. In the present embodiment, for the non-standard signal, the broadcasting system is discriminated depending on whether or not the non-image portion is inserted, and thus, regardless of whether or not the input video signal is the standard signal, It is possible to judge various methods. By setting the screen mode based on this determination result, it is possible to display in the optimum mode according to the method.

[0072]

As described above, according to the present invention, there is an effect that it is possible to determine the system of the input video signal.

Further, the present invention has an effect that the optimum mode can be set according to the system of the input video signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a television receiver according to the present invention.

FIG. 2 is an explanatory diagram for explaining a letterbox format signal.

FIG. 3 is a block diagram showing a specific configuration of a signal identification circuit in FIG.

FIG. 4 is a block diagram showing a specific configuration of a second generation EDTV identification circuit in FIG.

5 is a block diagram showing a specific configuration of a non-image portion detection circuit in FIG.

6 is a graph showing the characteristics of the non-linear circuit 46 in FIG.

7 is a block diagram showing a specific configuration of a vertical BPF 43 in FIG.

8 is a block diagram showing a specific configuration of a standard detection circuit shown in FIG.

FIG. 9 is an explanatory diagram for explaining an identification signal of a second generation EDTV signal.

[Explanation of symbols]

2 ... Y / C separation and color demodulation circuit, 3 ... Second generation EDTV
Processing circuit, 4 ... Signal identification circuit, 6 ... Selection circuit, 7 ... Monitor

Claims (8)

[Claims] 1. A video signal processing means for performing predetermined signal processing on an input video signal based on a wide aspect television signal or a current television signal in which a predetermined identification signal is multiplexed, and supplying the video signal to a monitor, said input video signal. Is a standard signal or a non-standard signal, and when the standard signal is detected, the input video signal is based on whether the identification signal is multiplexed with the input video signal. The method of
When it is detected that the input signal is a non-standard signal, the input image signal has a non-image portion, the input image signal system is discriminated and the discrimination result is outputted, And a control means for controlling the display of the monitor based on the above. 2. The television receiver according to claim 1, wherein the wide aspect television signal is a second generation EDTV system signal and the current television signal is an NTSC system signal. . 3. The signal identifying means determines whether the input video signal is a standard signal depending on whether or not the phase of the color subcarrier of the input video signal and the phase of the vertical synchronizing signal have a constant relationship. The television receiver according to claim 1, wherein the television receiver detects whether the signal is a non-standard signal. 4. The television receiver according to claim 3, wherein the non-standard signal is a reproduction signal from a magnetic reproduction device. 5. The signal identifying means includes a confirmation signal detecting means for detecting an identification signal included in the identification signal, and a decoding means for decoding an identification code in NRZ format and an identification code in color subcarrier format. When the confirmation signal is not detected, a determination output indicating that the input video signal is an NTSC system signal is output, and when the confirmation signal is detected, the output of the decoding means is used as the determination output. The television receiver according to claim 2, wherein: 6. The signal identifying means uses the level of at least one of a horizontal low frequency component, a horizontal high frequency component and a vertical high frequency component of the input video signal to determine whether the input video signal has a non-image portion. It detects whether or not.
The television receiver described in. 7. The control means, when the signal identifying means indicates that the input video signal is a signal of a second generation EDTV system, the control means determines the non-image according to the aspect ratio of the monitor. 3. The television receiver according to claim 2, wherein a blanking process is performed on the image portion or a process for displaying the main image portion on the entire screen. 8. The main image part of the input video signal, wherein the video signal processing means uses the reinforcement signal multiplexed in the non-image part when the input video signal is a signal of the second generation EDTV system. 3. The television receiver according to claim 2, wherein the number of scanning lines is increased.