JPH036979A - Television receiver - Google Patents

Abstract

PURPOSE:To reproduce a subcarrier with high phase accuracy by eliminating a color burst signal for a prescribed horizontal scanning period of a vertical overscan period in one television signal, receiving two television signals with different aspect ratio not eliminated from other television signals so as to discriminate the aspect ratio of a received television signal. CONSTITUTION:A color burst detection circuit 19 extracts a signal of the 263-th H horizontal scanning period from a reception television signal inputted from an input terminal 11. The gate signal for the extraction is generated based on reproduced synchronizing signals HD2, VD2 outputted from a superimposing period discrimination circuit 17. When no color burst signal is included in the extracted signal, it is discriminated that the aspect ratio of the reception television signal is the aspect ratio of the wide aspect system. On the other hand, when the color burst signal is included, it is discriminated that it is the aspect ratio of the NTSC system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a television receiver capable of receiving television broadcasts having a larger aspect ratio than current television broadcasts. (Prior Art) In recent years, a wide aspect system has been proposed for television broadcasting, which displays a screen with a larger aspect ratio than the current NTSC system screen.

In this wide aspect method, the current NTSC
In order to maintain compatibility with the television signal (hereinafter referred to as
The wide aspect signal) is divided into a part with the aspect ratio of the NTSC system (hereinafter referred to as the main signal) and the other part (hereinafter referred to as the additional signal), and the additional signal is multiplexed with the main signal and transmitted. That is what is being considered.

According to such a configuration, an NTSC television receiver can reproduce a screen having an NTSC aspect ratio using the main signal, and a wide aspect television receiver can reproduce a screen having an NTSC aspect ratio using the main signal. By combining the signal and the additional signal, a screen with a wide aspect aspect ratio can be reproduced.

Note that the additional signal multiplexing method includes a time division multiplexing method and a frequency multiplexing method. The latter is, for example, 'rEEE T
RANS 0n BROADCASTING, Vol BC-33°N
o, 4 DECEMBER 1987'.

By the way, in the time division multiplexing system, in order to divide a received television signal into a main signal and an additional signal, it is necessary to accurately detect the multiplexing position of the additional signal with respect to the main signal. Therefore, this time division multiplexing system requires a synchronization signal regeneration circuit with high phase accuracy.

A conventional synchronization signal regeneration circuit is a phase-locked loop circuit that includes a phase comparison circuit that separates a horizontal synchronization signal from a received television signal and converts the phase difference between the separated output and the reproduced synchronization signal into a DC component in an analog manner. (Hereinafter, PLL
The synchronous signal was regenerated by a circuit (referred to as a circuit).

According to such a configuration, even if the received television signal contains an impulse-like noise signal, it is possible to reproduce a synchronization signal with high phase accuracy due to the flywheel effect of the PLL circuit.

However, since the configuration converts the phase difference into a DC component in an analog manner, there was a problem that if the received television signal contained a ghost signal, the phase of the reproduced synchronization signal would deviate significantly from the original phase. .

In order to solve this problem, the applicant for the patent in question
In Japanese Patent Application No. 63-112270 filed on May 9, 1983, phase reference data synchronized with a color burst signal is placed at a predetermined position in the vertical blanking period of a color television signal, and based on this phase reference data. The application was filed for a synchronization signal regeneration circuit that regenerates synchronization signals.

To apply this synchronizing signal reproducing circuit to a wide aspect type synchronizing signal reproducing circuit, it is sufficient to delete the picture signal in a predetermined horizontal scanning period of the vertical overscan period and insert phase reference data into this deleted region.

However, wide aspect television broadcasting
For the time being, it is thought that it will be broadcast between the current NTSC system. In this case, in the NTSC television signal (hereinafter referred to as NTSC signal), the picture signal exists at the same position as the superimposition position of the phase-based data in the wide aspect signal. Therefore, when an NTSC signal is received by a wide aspect television receiver, the position corresponding to the superimposition position of the phase reference data is
If a picture signal similar to the phase reference data exists, the synchronization signal generation circuit will malfunction.

In order to solve this problem, it is necessary to automatically determine the aspect ratio of the received television signal and, in the case of NTSC broadcasting, to avoid using the above-mentioned synchronization signal reproducing circuit.

However, until now, there has been no television receiver that can automatically make this determination.

Next, in the frequency multiplexing method, if the additional signal is not demodulated with high precision, when the main signal and the additional signal are combined, a gap will appear between the two on the screen. In order to prevent this problem, it is necessary to reproduce subcarriers with high phase accuracy.

However, conventional television receivers have been unable to reproduce subcarriers with high phase accuracy.

(Problem 8 to be Solved by the Invention) As described above, the reality is that conventional television receivers have not yet been able to adequately cope with the emergence of the wide aspect format.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a television receiver that can fully cope with the emergence of wide aspect formats.

[Structure of the Invention] (Means and Effects for Solving the Problems) To achieve the above object, the present invention provides a method in which, in one television signal, a color burst signal is transmitted during a predetermined horizontal scanning period of a vertical overscan period. receiving two television signals having different aspect ratios, such that the color burst signal is deleted and the other television signal is not deleted, and determining whether or not the color burst signal is present in the predetermined horizontal scanning period. Accordingly, the aspect ratio of the received television signal is determined.

Thereby, the aspect ratio of the received television signal can be automatically determined.

Further, in the present invention, phase reference data synchronized with the color burst signal is sent as a television signal during a predetermined horizontal scanning period of the vertical overscan period, instead of the color burst signal and the picture signal, ffi! detects the phase reference signal from the received television signal based on the color burst signal, and regenerates a subcarrier for demodulating the additional signal in synchronization with this detection output. It was designed to do so.

According to such a configuration, since the color burst signal is not affected by the coast signal, subcarriers with high phase accuracy can be reproduced even under ghost interference.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention.

In FIG. 1, the color subcarrier reproducing circuit 12, the frequency dividing circuits 1B, 14, 15, the phase reference data reproducing circuit 16, the ball amount period determining circuit 17, and the pattern detecting circuit 18 are described in the above-mentioned Japanese Patent Application No. 63-112270. This constitutes a synchronous signal reproducing circuit having almost the same configuration as the described synchronous signal reproducing circuit.

Here, before explaining the configuration that characterizes the present invention, first, the synchronization signal reproducing circuit will be explained.

In FIG. 1, 11 is an input terminal to which a received wide aspect signal or NTSC signal is input.

During the 263H (LH is one horizontal scanning period) horizontal scanning period of the wide aspect signal input from this input terminal 11, phase reference data P indicating the phase reference of the reproduction synchronization signal is input.
D is superimposed. Television (B゛ No. 263H
The eye has a time width of 0.5H, as shown in FIG. As shown in FIG. 3(a), the phase reference data PD'' is superimposed on the 263H horizontal scanning period with the 263H color burst signal BU and picture signal deleted. The person position is set, for example, to a position separated by a predetermined number of clocks from the trailing edge of the horizontal synchronization signal HD with reference to the clock of the color burst signal BU.
This is binary NRZ format digital data with a data rate of . As such phase reference data PD, data with a sharp autocorrelation function peak, such as Parr force series data, for example, -1110010'' can be considered.

Furthermore, the clock phase of this phase reference data PD is synchronized with the color burst signal BU. That is, the phase of the phase reference data PD is set to have the same phase as the color burst signal BU or a predetermined phase difference. In the following description, it is assumed that the clock phase of the phase reference data PD has the same phase as the color burst signal BU.

On the other hand, the above-mentioned phase reference data PD is not inserted into the NTSC signal input manually from the input terminal 11.

Therefore, the color burst signal BU and the picture signal are inserted in the 263H horizontal scanning period of the N T SC (j number).

Since the above-mentioned synchronization signal regeneration circuit reproduces the synchronization signal based on the phase reference data PD, this synchronization signal regeneration circuit operates when receiving the wide aspect signal. That is, the wide aspect signal input from the input terminal 11 is supplied to the color m+J carrier wave reproducing circuit 12. This color subcarrier reproducing circuit 12 reproduces the color subcarrier CW of frequency fSC in synchronization with the color burst signal BU.

The color subcarrier reproducing circuit 12 further binarizes the reproduced color subcarrier CW to obtain a frequency f. clock signal C
At the same time, this clock signal No. 13 CI is multiplied by 4 to generate a clock signal C2 having a frequency of 4 fSC.

The clock signal C2 with a frequency of 4fsc is divided by 1/455 by the frequency dividing circuit 13, and then divided by 172 by the frequency dividing circuit 14.
The frequency is divided. The frequency divided output of the frequency dividing circuit 13 is further divided by 11525 in the frequency dividing circuit 15.

Here, there is a difference between the color subcarrier frequency fsc and the horizontal synchronization signal frequency fH1 and the vertical synchronization signal frequency fv.
There is a relationship of (455/2) fH fH - (525/2) fv. Therefore, the frequency divider circuit 14 obtains a signal of frequency fH. This signal is the regenerated underwater synchronization signal H
D. Further, a signal with a frequency fv is obtained from the frequency dividing circuit 15, and is used as a reproduced vertical synchronization signal VD.

The wide aspect signal supplied to the input terminal 11 is further supplied to a phase reference data reproducing circuit 16.

In the phase reference data reproducing circuit 16, the phase reference data PD is reproduced based on the clock signal c1. That is, the phase reference data reproducing circuit 16 first binarizes the input signal. This binarized output has a frequency f, which is output from the color subcarrier reproducing circuit 12. It is sampled with the clock signal C1. Thereby, the phase reference data PD is discretized and reproduced. In this case, the tenth clock position of the phase reference data PD and the clock signal C1 are both synchronized with the color burst signal BU, so if the input signal is sampled using the clock signal C0, the phase reference data PD can be reliably reproduced. be able to.

The reproduction output of the phase reference data reproduction circuit 16 is valid only during the superimposition period of the phase reference data PD.

This superimposition period is determined by the superimposition period determination circuit 17.

That is, this superimposition period determination circuit 17 separates the horizontal synchronization signal from the input signal, and reproduces the horizontal synchronization signal HD and the vertical synchronization signal VD in synchronization with the separated output. Then, this reproduction synchronization signal HD2. The superimposition period of the phase reference data PD is determined based on VD2. This superimposition period determination signal S.

is shown in FIG. 3(c).

The reproduction output of the phase reference data reproduction circuit 16 is supplied to the pattern detection circuit 18. This pattern detection circuit 18 is
When the pattern "1110010" is detected from the input signal, it is assumed that the phase reference data PD has been detected, and a detection pulse P as shown in FIG. 3(b) is output. This detection pulse P causes the frequency dividing circuits 13, 14 .
15 is reset. As a result, the frequency dividing circuit 13゜1
4.15 is reset at the superimposition position of the phase reference data PD. As a result, the reproduction synchronization signal HD.

The phase of VD is set to the reference phase defined by the phase of phase reference data PD.

FIG. 4 is a circuit diagram showing an example of a specific configuration of the color subcarrier reproducing circuit 12. As shown in FIG.

In FIG. 4, a wide aspect signal input from an input terminal 11 is supplied to a switch 121 and a synchronous separation circuit 122. The synchronization separation circuit 122 separates the horizontal synchronization signal HD as shown in FIG. 5(b) from the wide aspect signal shown in FIG. 5(a) supplied to the input terminal 11.

Based on this separated output, the pulse generating circuit 123 generates the burst gate pulse GP shown in FIG. 5(C). This burst gate pulse GP causes switch 2
21 is turned on.

As a result, the color burst signal BU included in the wide aspect signal is transmitted to the phase comparator circuit 124, the loop filter 125, the voltage controlled oscillator circuit (hereinafter referred to as VCO) 1
The signal is supplied as a reference signal to a PLL circuit consisting of 26 circuits.

This causes the color burst signal BU to be output from the VCO 126.
Frequency synchronized with f8. A color subcarrier CW is output.

This color subcarrier CW is precisely synchronized with the color burst signal BU even under ghost disturbances.

The color subcarrier CW output from the PLL circuit is supplied to the comparator 127, and the zero cross point is set as the reference level.
Valued. As a result, a clock signal CI having a frequency fSC is obtained. In Fig. 6(a), the color subcarrier CW is shown.
The clock signal C1 which is the binary output is shown in the same figure (b). This clock signal C0 is obtained with an accuracy of about six nanoseconds (nsec).

The clock signal C1 is output by the digital PLL circuit 128.
It is multiplied. As a result, the frequency 4 shown in FIG. 6(C)
Clock signal C2 is generated at fsc.

By the way, the frequency fsc is fsc” (455/2)X (525/2)X fv
As shown, there is a phase relationship that goes around once in four fields. Therefore, the phase reference data PD is superimposed on the 263H horizontal scanning period every four fields, for example. As a result, the phase of the reproduction synchronization signals HD, , VD, is 4.
The field is modified once.

FIG. 7 is a circuit diagram showing the configuration of a synchronization signal reproducing circuit provided in the above-mentioned superimposition period determination circuit 17.

In FIG. 7, a color television signal supplied to an input terminal 171 is supplied to a synchronization separation circuit 172, where horizontal synchronization signal 1 (D) is separated. VCO175 in circuit 173
The phase is compared with the output of The comparison result is supplied to the VCO 175 as a control signal through the loop filter 174.

Thereby, the oscillation frequency of the VCO 175 is controlled, and an oscillation output synchronized with the separated output of the horizontal synchronization signal HD is obtained. The oscillation output of this VCO 175 is supplied to an output terminal 176 and also to the phase comparison circuit 174 as a comparison signal. The oscillation output supplied to the output terminal 176 is used as the reproduced horizontal synchronizing signal HD2, and is divided appropriately to produce the reproduced vertical synchronizing signal VD.
Used as 2.

Phase comparison circuit 173, loop filter 174, VCO1
75, the PLL circuit consists of reproduction synchronization signals HD2. V.D.
It functions to stabilize the phase of 2. That is, the synchronization separation circuit 172 generally separates the horizontal synchronization signal HD by slicing the leading end of the received horizontal synchronization signal HD. Therefore, this separated output often contains impulse-like noise signals. Therefore, the reproduction synchronization signal HD2. V.D.

When obtained, this reproduction synchronization signal HD2. The quality of VD2 deteriorates, and stable synchronous operation cannot be obtained in image display. Therefore, a PLL circuit is provided to avoid being affected by such noise signals.

FIG. 8 shows signal waveforms at various parts in FIG. 7.

8(a) shows the horizontal synchronization signal HD separated by the sync separation circuit 172, FIG. 8(b) shows the oscillation output S2 of the VCO 175, and FIG. 8(c) shows the phase comparison of the phase comparison circuit 173. Output S1 is shown.

FIG. 8 shows a state in which the operation of the PLL circuit is locked. As is clear from this figure, PLL
The circuit operates so that the DC component of the phase comparison output S1 of the phase comparison circuit 173 becomes zero. This is to reduce the influence of impulse-like noise signals by utilizing the Fuller wheel effect of the PLL circuit.

Since the reproduction synchronization signals HD, . but,
As shown in FIG. 3(c), this superimposition period determination signal S6 is for determining a relatively large period including before and after the actual superimposition period of the phase reference data PD, so even if the phase is slightly shifted, there is no problem. There isn't.

Next, the features of this invention will be explained.

First, the part that determines the aspect ratio will be explained.

This aspect ratio determination section is comprised of a superimposition period determination circuit 17 and a color burst detection circuit 19.

The color burst detection circuit 19 extracts the signal of the 263H horizontal scanning period from the received television signal inputted from the input terminal 11 . The gate signal for this extraction is the reproduction synchronization signal HD 2 output from the superimposition period determination circuit 17.

Generated based on vD2. Then, by determining whether or not the color burst signal BU is included in this extracted signal, the aspect ratio of the received television signal is determined. That is, the color bust signal BU
is not included, it is determined that the aspect ratio of the received television signal is that of the wide aspect method.

On the other hand, if the color burst signal BU is included,
The aspect ratio is determined to be that of the NTSC system.

Note that this determination signal is supplied to the selection circuits 20 and 21 as a control signal.

When the selection circuit 20.21 obtains a determination signal indicating that the aspect ratio of the received television signal is that of the wide aspect method, the selection circuit 20.21 outputs the reproduction synchronization signals HD, VD from the frequency dividing circuit 14.15. Select the playback synchronization signal HD, VDI. On the other hand, when a determination signal indicating that the aspect ratio is the NTSC format is obtained, the reproduction synchronization signals HD2 and vD2 outputted from the superimposition period determination circuit 17 are selected as the reproduction synchronization signals HD and VD.

As a result, when receiving wide aspect television broadcasting in which phase reference data PD is transmitted, the reproduction synchronization signal HD synchronized with this phase reference data PD,...
VDI is obtained. As a result, the multiplexed position of the additional signal can be detected accurately.

On the other hand, in NTSC, the phase reference data PD is not transmitted.
When receiving the signal, the synchronization signal HD2. VD2 is selected. Thereby, it is possible to prevent the reproduction synchronization signals HD, HD2 output from the frequency dividing circuits 14, 15 from being used even though the phase reference data PD is not transmitted.

Finally, the part for reproducing subcarriers will be explained.

This subcarrier regeneration part includes a color subcarrier regeneration circuit 12,
phase reference data regeneration circuit 16, superimposition period determination circuit 17,
It consists of a pattern detection circuit 18, a counter 22, and a ROM 23.

Color subcarrier regeneration circuit 12, phase reference data regeneration circuit 16
, the superimposition period determination circuit 17, and the pattern detection circuit 18 have been described above, so here, the operations of the counter 22 and the ROM 23 will be explained.
The explanation will focus on the operation.

The counter 22 is reset by the detection pulse P of the phase reference data PD output from the pattern detection circuit 18, and is reset by the frequency 4 f output from the color subcarrier regeneration circuit 12.
SC clock signal C2 is counted. The count output of this counter 22 is supplied to the ROM 23 as address data.

This ROM 23 stores subcarriers having the same waveform as the subcarriers used for modulating the additional signal on the transmitting side. This subcarrier is read out based on the count output of the counter 22. Therefore, the ROM 23 outputs subcarriers synchronized with the phase reference data PD.

This subcarrier is used as a regenerated subcarrier to demodulate the additional signal.

As described above, in this embodiment, the television signal on which the phase reference data PD is superimposed instead of the color burst signal BU and the picture signal is received between the 263H horizontal scanning sections as the wide aspect signal. The aspect ratio is determined by determining whether or not a color burst signal BU is included in the received television signal.

According to such a configuration, wide aspect broadcasting and NT
Even when SC broadcasts are mixed, the aspect ratio of the received television signal can be automatically determined.

Further, in this embodiment, subcarriers are reproduced using phase reference data PD sent in synchronization with color burst signal BU.

According to such a configuration, the quality of the color burst signal BU hardly deteriorates even under ghost failure, so that the phase reference data can be accurately reproduced. This makes it possible to reproduce subcarriers with high phase accuracy.
It is possible to prevent the joint between the main signal and the additional signal from appearing on the screen.

Furthermore, in this embodiment, since the aspect ratio determination circuit is configured using a synchronization signal reproducing circuit, it is possible to create a state in which there is no color burst signal BU by superimposing the phase reference signal PD. There are advantages.

Furthermore, in this embodiment, the subcarrier regeneration circuit is configured using a synchronization signal regeneration circuit, so that the subcarrier can be regenerated using the synchronization signal HDI and the phase reference data PD for VDI regeneration. It has the advantage of being possible.

In addition, in this embodiment, the wide aspect signal is
Even when receiving with a C-scheme television receiver, low image quality does not occur due to deletion of the picture signal. This means that the underwater scanning period during which the picture signal is deleted is 263.
This is because it is set to the H-th horizontal scanning period. That is, in an NTSC television receiver, such a horizontal scanning period is included in the vertical overscanning period and does not appear in the image display area of the television receiver.

Furthermore, in this embodiment, since the horizontal scanning period in which the color burst signal BU is deleted is limited to one horizontal scanning period, the reproduction of the color subcarrier CW is not affected equally. This is because the time constant of the PLL circuit (see FIG. 4) of the color subcarrier regeneration circuit 12 is usually large, so that this degree of loss of the color burst signal can be sufficiently covered.

Although one embodiment of the present invention has been described above in detail, the present invention is not limited to this embodiment.

In the previous embodiment, the case where the data rate of the phase reference data PD was set to fsc was explained, but the horizontal synchronization frequency f
. Any rate may be used as long as it has a rate that is an integral multiple of . For example, in teletext broadcasting currently in practical use, f, - (8/5) f sc = 364
Although a data rate of f H is used, this data rate may also be used in the present invention. In addition to this, (2X i/ 5) f sc (however, i-1,..., 4) (2Xj/7) fsc (however, J-1,..., 8) (2Xk/13) A data rate such as fsc (k-1, . . . , 15) may be used.

In this way, if the phase reference data PD has a data rate that is an integral multiple of the horizontal synchronization frequency fH, by appropriately setting the division ratios of the frequency division circuits 13.14 and 1.5 shown in FIG. , reproduction synchronization signals HD, ,VD, can be obtained.

Furthermore, in the previous embodiment, a case was explained in which the aspect ratio determination circuit and the subcarrier regeneration circuit were configured using the synchronization signal regeneration circuit, but these circuits may be provided independently of the synchronization signal regeneration circuit. Good too.

In addition, when the aspect ratio determination circuit is provided independently from the synchronization signal determination circuit, the phase reference data PD is not always ffi during the horizontal scanning period in which the color burst signal BU is deleted.
There's no need to fold it.

In addition, when the subcarrier regeneration circuit is provided independently from the synchronization signal regeneration circuit, the synchronization signal HD is used.

In addition to the phase reference data PD for VD and reproduction, phase reference data exclusively for reproduction of subcarriers may be used.

In addition, in the previous embodiment, the case where the area in which the color burst signal BU is deleted is set in the 263H horizontal scanning period, but any horizontal scanning period within the vertical overscan period can be set. It may be set to Moreover, it goes without saying that the period is not limited to one horizontal scanning period.

In addition, in the previous embodiment, the NTSC system was explained as a television broadcasting system other than the wide aspect system.
Other Television Broadcasting Systems % It goes without saying that the present invention can be modified in various other ways without departing from the gist thereof.

[Effects of the Invention] As described above, according to the present invention, it is possible to cope with the emergence of the wide aspect method.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG.
3 are signal waveform diagrams for explaining the operation of FIG. 1, FIG. 4 is a circuit diagram showing an example of a specific configuration of the color subcarrier regeneration circuit shown in FIG. 1, and FIGS. Figure 6 is the fourth
7 is a circuit diagram showing an example of a specific configuration of a part of the superimposition period determination circuit shown in FIG. 1, and FIG. 8 is a signal waveform diagram for explaining the operation of FIG. 7. FIG. 3 is a signal waveform diagram for 11... Input terminal, 12... Color subcarrier regeneration circuit,
13.14.15... Frequency dividing circuit, 16... Phase reference pig regeneration circuit, 17... Superimposition period determination circuit, 18...
Pattern detection circuit, 19... Burst detection circuit, 20
．． 21... Selection circuit, 22... Counter, 23...
・ROM.

Claims (3)

[Claims] (1) A first television signal and a second television signal whose aspect ratios are different from each other, and in which the color burst signal is deleted in a predetermined horizontal scanning period of the vertical overscan period. the television signal, and is configured to determine the aspect ratio of the received television signal by determining whether or not the color burst signal is present in the predetermined horizontal scanning period of the received television signal. A television receiver characterized by: (2) The television according to claim 1, wherein the second television signal has phase reference data superimposed in place of the color burst signal and picture signal during the predetermined horizontal scanning period. John receiver. (3) Television reception that receives a television signal in which an additional signal for enlarging a first aspect ratio to a larger second aspect ratio is frequency-multiplexed onto the main signal having the first aspect ratio. The machine receives, as the television signal, a television signal on which phase reference data synchronized with the color burst signal is superimposed, instead of the color burst signal and the picture signal, during a predetermined horizontal scanning period of the vertical overscan period. , a phase reference data detection means for detecting the phase reference data based on the color burst signal included in the television signal; and a phase reference data detection means for demodulating the additional signal in synchronization with the detection output of the phase reference data detection means. A television receiver comprising subcarrier reproducing means for reproducing subcarriers.