JP3229787B2 - Broadcast signal processing device, television receiver and VTR using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color demodulator, a television receiver and a VTR using the same, and more particularly, to a color demodulator for automatically determining a color system, and a television receiver and a VTR using the same.

[0002]

2. Description of the Related Art Color systems (PAL, NTSC, SEC)
AM) is incorporated in the color demodulation circuit. This color demodulation circuit is generally integrated in an IC, and therefore, the color system automatic discrimination function is also provided in these ICs.
Built in. Therefore, the operation of the automatic determination of the color system is determined at the stage of developing the IC. Therefore, I
After the development of C is completed, the change or addition of this operation involves a circuit change inside the IC.

The color demodulation circuit is generally a bipolar IC,
The degree of integration is increasing year by year, and the tendency of increasing the scale of the entire circuit is remarkable. Changing or adding the operation of the automatic determination of the color system often involves changing the connection of the circuit inside the IC or adding a circuit structure, thereby increasing the area of the IC chip. An increase in chip area leads to an increase in cost.

When the area of a part of an already completed IC pattern layout increases due to the change or addition, the increased amount must move a peripheral circuit pattern. However, since the elements to be moved are enormous, the change requires time and effort. Further, when the layout of the chip is changed, the characteristics of another circuit inside the IC may change.

In many cases, it is necessary to change the operation of the automatic determination of the color system in a special situation in which the automatic determination cannot be accurately performed by the operation. This is to implement measures for normal operation. Naturally, it is a countermeasure, so it is necessary to confirm the effect as soon as possible and implement the countermeasure.

However, it takes several more months to change the IC pattern and produce the actual IC as described above, and if the countermeasure effect is not sufficient, the change of the IC for further improvement is required. Need to do. In this,
Implementation of the measures is being delayed. Hereinafter, a specific description will be given with reference to FIG. FIG. 3 shows a conventional television receiver 1 provided with a color demodulation circuit, and the operation of automatic color system discrimination will be described. In the example of FIG. 3, PAL and SEC
It has a function of automatically determining AM. IC "L
The A7681 ″ PAL demodulation IC 1a includes an NTSC demodulator (not shown) and a PAL demodulator 2;
There is no automatic discrimination function between TSC and PAL. IC "A
N5635N "SECAM demodulation IC1b is SECAM
A demodulator 3 is provided.

The operation of automatically discriminating between PAL and SECAM will be described below. SECAM demodulation IC1b
Then, the SECAM killer circuit 4 determines whether the chroma signal input from the 14th pin is a SECAM signal or a non-SECAM signal. When the SECAM killer circuit 4 is turned off, the chroma signal from the 14th pin is determined as a SECAM signal.

The SECAM killer circuit 4 extracts a SECAM burst signal from the chroma signal from the 14th pin by a burst gate pulse formed by shaping the horizontal flyback pulse input from the 11th pin.
This SECAM burst signal is FM-demodulated in the SECAM killer circuit 4 and sent to the ID killer filter, where the demodulation level is replaced with a DC voltage substantially corresponding to the frequency of the SECAM burst signal. The SECAM killer circuit 4 determines whether or not the signal is a SECAM signal based on the result of comparing the DC voltage with a comparator.

In this way, the SECAM killer circuit 4
Will be described assuming that the chroma signal is a SECAM signal. SEC obtained by demodulation by SECAM demodulator 3
The AM color difference signals, ie, the RY and BY signals are
The color difference signal is sent to a switch circuit called an L-SECAM switch 5.

[0010] The PAL / SECAM switch 5 is also adapted to be able to input RY and BY signals from the PAL demodulator 2. SECAM killer circuit 4 is SE
If it is determined that the signal is a CAM signal, the PAL / SECAM switch 5 outputs the RY and BY signals from the SECAM demodulator 3.
The signal is selected and sent to the matrix circuit 6 in the SECAM demodulation IC 1b.

In the matrix circuit 6, RY and B-
A GY signal is generated from the Y signal. These three color difference signals are output from pins 1, 2, and 3 of the SECAM demodulation IC 1b, respectively, and these color difference signals are sent to the CRT / drive amplifier 7 and reproduced on the CRT 8. That is, if the SECAM killer circuit 4 determines that the signal is a SECAM signal, even if a color difference signal is sent from the PAL demodulator 2,
The PAL color difference signal is not sent to CRT8.

Next, a PAL signal is input and SECAM
The case where the killer circuit 4 determines that the signal is a non-SECAM signal will be described. The PAL demodulation IC 1a operates in a PAL forced mode according to a user setting. 4 of PAL demodulation IC1a
The chroma signal input from pin 0 is the ACC killer circuit 9.
To the PAL demodulator 2 via R, Y and BY.
The signals are demodulated into signals and the PAL demodulation ICs 1a and 23
Output from each pin.

The PAL RY and BY signals are sent to the PAL / SECAM switch 5 via pins 22 and 4 of the SECAM demodulation IC 1a, respectively. SEC
In the AM demodulation IC 1b, the SECAM killer circuit 4
Since the signal is determined to be ECAM, the signal from the SECAM demodulator 3 is not selected, and the RY and BY signals from the PAL demodulator 2 input from pins 22 and 4 are selected. RY and BY of the selected PAL
The signal is sent to the matrix circuit 6 in the SECAM demodulation IC 1b.

In the matrix circuit 6, RY and B-
A GY signal is generated from the Y signal. These three color difference signals are output from pins 1, 2 and 3 of the SECAM demodulation IC 1b, and these color difference signals are sent to the CRT / drive amplifier 7 and reproduced on the CRT 8. As mentioned above,
The automatic discrimination between PAL and SECAM is based on SECAM demodulation I
Based on the operation of the SECAM killer circuit 4 of C1b as a criterion, it is determined which color difference signal is to be selected and reproduced on the screen. That is, the television receiver 1 shown in FIG.
In this example, the PAL / SECAM switch 5 controlled according to the output signal of the SECAM killer circuit 4 of the SECAM demodulation IC 1b realizes automatic switching between PAL and SECAM.

[0015]

It is assumed here that SECA
SE even though M killer circuit 4 is not SECAM
A case will be considered where the operation of the PAL ACC killer circuit 9 is changed to a criterion in order to prevent erroneous determination as a CAM. Then, although not shown, SECAM
The chroma switch (selection of pins 14 and 15 (not shown)) and the PAL / SECAM switch (color difference signal switching) 5 in the demodulation IC 1b are provided by the PAL demodulation IC 1a.
Of the ACC killer circuit 9 (eg, killer on /
It must be changed to a circuit controlled by High / Low when turned off. For this purpose, a killer output terminal must be provided in the PAL demodulation IC 1a, and a corresponding input terminal must be provided in the SECAM demodulation IC 1b. As a result, these two ICs, that is, PAL demodulation circuit 1a and SE
With the circuit change of the CAM demodulation circuit 1b, it is necessary to further change the IC package.

SUMMARY OF THE INVENTION It is, therefore, a primary object of the present invention to provide a color demodulation device capable of changing a color system discriminating operation without changing a circuit, and a television receiver and a VTR using the same. Another object of the present invention is to provide a color demodulation method capable of changing a color system discriminating operation without changing a circuit.

[0017]

According to the present invention, a plurality of TVs are provided.
Any one of a plurality of broadcast signals individually corresponding to the broadcast system
Input means for inputting one TV signal to each of a plurality of TV broadcasting systems.
The corresponding color demodulation method is adopted and the input
Outputs a demodulation enable / disable signal indicating whether the transmitted signal can be color demodulated.
A plurality of color demodulation means to output audio signals from input broadcast signals
Filter means to extract, output from multiple color demodulation means
Multiple demodulation enable / disable signals selectively
Discriminating means for individual discrimination, and the same demodulation enable / disable signal status
When it is determined that the state can be demodulated continuously multiple times,
Set the frequency corresponding to the enable / disable signal to the filter means.
This is a broadcast signal processing device including a setting unit.

[0018]

[0019]

According to the first aspect of the invention, the video signal included in the received broadcast signal is supplied to, for example, a color killer circuit provided for each of the plurality of demodulators. Each color killer circuit determines whether a corresponding demodulator can color-demodulate the video signal based on a color burst signal included in the received broadcast signal, and outputs a determination signal. For example, the microcomputer selects a specific demodulator based on the discrimination signal.

If a priority order for selecting a demodulator is set, a specific demodulator is selected according to the priority when a plurality of discrimination signals indicating that demodulation is possible are output. . In addition, if a plurality of trap means for trapping audio signals included in broadcast signals corresponding to a plurality of TV broadcast systems are provided, and a specific trap means is selected based on the discrimination signal, the color killer circuit can output the audio signal. Is never entered.

A television receiver or a VTR is constructed using such a color demodulator. In the second invention, for example, the microcomputer first selects a specific demodulator, and then determines whether or not the received broadcast signal can be demodulated by the demodulator based on the color burst signal. If the demodulator can demodulate, the microcomputer confirms the selection.

[0022]

According to these inventions, it is possible to change the discrimination operation of the color system without changing the circuit. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a television receiver 10 of this embodiment includes a color demodulator 12. The color demodulation device 12 includes a color demodulation circuit 14 and a microcomputer (microcomputer) 16. The color demodulation circuit 14 includes a PAL demodulator 18, a SECAM demodulator 20, and an NTSC demodulator 2.
2 inclusive. An ACC killer circuit 24, an ID killer circuit 26, and an ACC killer circuit 28 are provided corresponding to the PAL demodulator 18, the SECAM demodulator 20, and the NTSC demodulator 22, respectively. These ACC killer circuits 2
4, ID killer circuit 26 and ACC killer circuit 28
Function as a determination unit for determining whether demodulation is possible or not.

That is, the video signal input from the terminal 30 is supplied to the ACC killer circuit 24, the ID killer circuit 26, and the ACC killer circuit 28, and it is determined whether or not the video signal can be demodulated. A killer signal indicating whether demodulation is possible is provided from the ACC killer circuit 24, the ID killer circuit 26, and the ACC killer circuit 28 to the microcomputer 16 outside the color demodulation circuit 14. In addition, PAL
Are AM-modulated and 90 per 1H
° phase shifted, NTSC color burst signal is AM modulated and not phase shifted, and SECAM color burst signal is FM modulated and modulation frequency changes every 1H Things. The ACC killer circuits 24 and 28 and the ID killer circuit 26 determine whether or not the input signal can be demodulated based on such a difference in the modulation method, phase, and frequency. When a killer signal indicating that demodulation is possible is output, the video signal is demodulated by the subsequent demodulator. For example, if the video signal is a PAL signal, a killer signal indicating that demodulation is possible is output from the ACC killer circuit 24, and the ID killer circuit 26 and AC
The C killer circuit 28 outputs a killer signal indicating that demodulation is impossible. In this case, the PAL demodulator 18
The signal is demodulated, but the SECAM demodulator 20 and NT
The SC demodulator 22 does not demodulate the PAL signal.

The color difference signals, that is, the RY and BY signals output from the PAL demodulator 18, SECAM demodulator 20, and NTSC demodulator 22 are supplied to a switch 32. The switching of the switch 32 is controlled in accordance with a color control signal from the microcomputer 16.
R of any of PAL, SECAM and NTSC
-Y and BY signals are selected and sent to the matrix circuit 34.

Here, the microcomputer 16 includes a memory 36, which stores a program for automatic discrimination of the color system as shown in FIG. The signal is stored. Therefore, the microcomputer 16 determines the areas P, S and N
Color demodulation circuit 1 according to the killer signal stored in
A color system control signal is output to 4 to indicate the color system to be demodulated.

The RY, BY, and GY signals, which are color difference signals, are sent from the matrix circuit 34 to the CRT / drive amplifier 38, and are reproduced on the CRT 40. The video signal from the terminal 30 is sent to the Y signal processing circuit 40, where the sharpness, contrast and brightness are adjusted, and sent to the CRT drive amplifier 38. As described above, in the television receiver 10, the color demodulation circuit 14
From the outside of the microcomputer 16, which method (PAL /
Whether the video signal is demodulated by SECAM / NTSC is controlled, and the demodulated signal to be output to the CRT 40 is determined.

The main operation of the television receiver 10 will be described with reference to FIG. First, in step S1 shown in FIG. 2, a PAL demodulation mode is set.
That is, the microcomputer 16 outputs a color control signal to the color demodulation circuit 14 so as to demodulate the video signal as a PAL signal. Then, the ACC killer circuit 24 determines whether or not the input video signal is a PAL signal. If the signal is a PAL signal, a killer signal “1” indicating that demodulation is possible is output. If the signal is not a PAL signal, a killer signal “0” indicating that demodulation is impossible is output. In step S3, this killer signal is stored in area P of memory 36.

Next, in step S5, the SECA
M demodulation mode is set. That is, the microcomputer 16
Demodulates the video signal as a SECAM signal,
A color control signal is output to the color demodulation circuit 14. Then, the ID killer circuit 26 outputs the video signal S
It is determined whether or not the signal is an ECAM signal. If the signal is a SECAM signal, a killer signal “1” indicating that demodulation is possible is output.
If it is not a signal, a killer signal "0" indicating that demodulation is impossible is output. In step S7, this killer signal is stored in area S of memory 36.

Next, in step S9, NTSC
The demodulation mode is set. That is, the microcomputer 16
A color control signal is output to the color demodulation circuit 14 so as to demodulate the video signal as an NTSC signal. Then, the ACC killer circuit 28 outputs the video signal as NT
It is determined whether the signal is an SC signal. The ACC killer circuit 28
If the video signal is an NTSC signal, it outputs a color signal "1" indicating that demodulation is possible, and if not, outputs a killer signal "0" indicating that demodulation is impossible. Step S11
In, this killer signal is stored in the area N of the memory.

Next, in step S13, the area P
It is determined whether the killer signal stored in each of area and area S is both “1”. If “NO”, the process proceeds to a step S15, and it is determined whether or not the killer signal stored in the area P is “1”. If "YES", the process proceeds to a step S17 to set the PAL demodulation mode. That is, at this time, the ACC killer circuit 24 operates by the color system control signal output from the microcomputer 16, the video signal is demodulated by the PAL demodulator 18, and the switch 32 selects the color difference signal from the PAL demodulator 18. Next, in step S19, it is determined whether or not the killer signal from the ACC killer circuit 24 has become "0". The processing is continued in the PAL demodulation mode unless the killer signal becomes "0", and if it becomes "0", the process returns to step S1.

If "NO" in the step S15, it is determined in a step S21 whether or not the killer signal stored in the area S is "1". If "YES", in step S23, the mode is set to the SECAM demodulation mode. That is, at this time, the ID killer circuit 26 operates according to the color system control signal from the microcomputer 16, the video signal is demodulated by the SECAM demodulator 20, and the switch 32 selects the color difference signal from the SECAM demodulator 20. Then, in step S25, it is determined whether or not the killer signal from the ID killer circuit 26 is "0". Unless the killer signal becomes "0", the process is continued in the SECAM demodulation mode. If it becomes "0", the process returns to step S1.

If "NO" in the step S21, it is determined whether or not the killer signal stored in the area N is "1" in a step S27. If "YES", in step S28, the NTSC demodulation mode is set. The video signal is demodulated by the NTSC demodulator 22. That is, at this time, the ACC killer circuit 28 is operated by the color system control signal output from the microcomputer 16, the video signal is demodulated by the NTSC demodulator 22, and the switch 32 selects the color difference signal from the NTSC demodulator 22. Then, in step S29, it is determined whether or not the killer signal from the ACC killer circuit 28 is "0". Unless the killer signal becomes "0", the process is continued in the NTSC demodulation mode. If it becomes "0", the process returns to step S1.

If "NO" in the step S27, it is determined that the broadcast is a monochrome broadcast, and the process returns to the step S1. Step S13
In step S13, "YES", that is, AC
If both the C killer circuit 24 and the ID killer circuit 26 output a killer signal "1" indicating that decoding is possible, the process proceeds to step S31. Step S13 becomes "YES" when either the ACC killer circuit 24 or the ID killer circuit 26 malfunctions because the color carrier frequency of PAL is close to the color carrier frequency of SECAM. Therefore, it is programmed in advance which of the SECAM demodulation mode and the PAL demodulation mode is to be prioritized according to the use area.

Then, in step S31, SEC
It is determined whether to give priority to the AM demodulation mode. SEC
If it is programmed to give priority to the AM demodulation mode, the process proceeds to step S33. In step S33, the SECAM demodulation mode is set, and in step S23
Is processed in the same way as Then, in step S35, it is determined whether or not the killer signal from the ID killer circuit 26 is "0".
The process is continued in the demodulation mode.
Return to

Step S31 returns "NO", that is, PA
If it is programmed to give priority to the L demodulation mode, the process proceeds to step S37. In step S37,
The PAL demodulation mode is set, and the same processing as in step S17 is performed. Next, in step S39, ACC
It is determined whether or not the killer signal from the killer circuit 24 is "0". If the killer signal does not become "0", the process is continued in the PAL demodulation mode.

Hereinafter, the operation of the television receiver 10 will be described.
This will be described more specifically. For example, if the video signal is NT
It is assumed that an SC signal is input. The microcomputer 16 first outputs a color control signal to the color demodulation circuit 14 so as to demodulate the video signal as a PAL signal. Then, the ACC killer circuit 24 operates. Since the input video signal (NTSC signal) is not a PAL signal,
The C killer circuit 24 sends to the microcomputer 16 a killer signal “0” indicating that the PAL demodulator 18 cannot demodulate the video signal.

Next, the microcomputer 16 converts the video signal into SE
A color control signal is output to the color demodulation circuit 14 so as to be demodulated as a CAM signal. Then
The ID killer circuit 26 operates. Since the input video signal is not a SECAM signal, the ACC killer circuit 24
The SECAM demodulator 20 sends a killer signal “0” to the microcomputer 16 indicating that the video signal cannot be demodulated.

Next, the microcomputer 16 converts the video signal to NT
A color control signal is output to the color demodulation circuit 14 so as to be demodulated as an SC signal. Then ACC
The killer circuit 28 operates. The input video signal is NT
Since the signal is an SC signal, the ACC killer circuit 28
A killer signal “1” indicating that the video signal can be demodulated by the C demodulator 22 is sent to the microcomputer 16.

Then, in the microcomputer 16, the video signal is NT
Recognizing that the signal is an SC signal, setting the demodulation mode to the NTSC demodulation mode, and setting the switch 32 to the NTSC demodulator 22
Select output from. In this way, the color system is searched sequentially according to the programmed operation,
The color system of the input video signal is automatically determined.
Since the television receiver 10 operates according to a program stored in the memory 36 of the microcomputer 16,
The operation may be changed by changing the program. Since the change of the operation of the IC of the color demodulation circuit 14 is not required for the change of the operation, if the EPROM or the one-time microcomputer is used, the operation after the change can be confirmed remarkably faster than before.

In this embodiment, the microcomputer 16
After searching for PAL, SECAM, and NTSC, PA
ACC killer circuit 24 for L and SECAM respectively
If the killer signal "1" indicating that demodulation is possible is output from the ID killer circuit 26, one of the PAL demodulation mode and the SECAM demodulation mode must be prioritized. In this embodiment, the priority is determined by a program. It can be easily set.

Further, in an area without the SECAM system or in a usage method, search for SECAM may be prohibited in a program. As described above, by rewriting a program according to a region to be used and needs, it is possible to flexibly and quickly develop an optimal color system automatic discrimination system.

Referring to FIG. 4, a television receiver 10 of another embodiment includes a tuner 46. The tuner 46 selects a signal of a desired channel from the TV high-frequency signal received by the antenna 44, and converts the signal into an intermediate frequency (IF) signal. The IF signal is passed through an amplifier 48 to 33.5.
MHz trap circuit 50. In the trap circuit 50, the signal selected by the tuner 46 is an NTSC broadcast signal and the color subcarrier frequency is 3.58 MHz.
In the case of, the signal is turned on by the control signal from the microcomputer 68, and the 33.5 MHz component of the given IF signal is trapped. The reason why such a trap circuit 50 is provided is that the next-stage SAW filter 52 has the filter characteristics shown in FIG.
This is because the audio signal S 'component of the Hz signal cannot be dropped, and the color signal and the audio signal beat in the demodulation circuit 54.

The IF signal output from the trap circuit 50 is supplied to a demodulation circuit 54 via a SAW filter 52, and the IF signal is demodulated by the demodulation circuit 54. Therefore, the demodulation circuit 54 outputs a demodulated signal having the spectrum shown in FIGS. That is,
When a PAL broadcast signal (PAL signal) is selected, a demodulated signal of the spectrum shown in FIG. 7A is output. When a SECAM broadcast signal (SECAM signal) is selected, FIG. The signal of the spectrum shown in B) is demodulated, and the color subcarrier frequency is set to 4.
43MHz broadcast signal (NTSC 4.43MHz signal)
Is selected, a demodulated signal having the spectrum shown in FIG. 7C is output, and a broadcast signal (NTSC 3.58M) having a color subcarrier frequency of 3.58 MHz in the NTSC system is output.
7D), a demodulated signal having the spectrum shown in FIG. 7D is output.

The demodulated signal is supplied to switches SW1 and SW2
Via the 4.5 MHz trap circuits 56 and 4.
It is supplied to a 5 MHz filter 60 or a 5.5 MHz trap circuit 58 and a 5.5 MHz filter 62. That is, when the demodulated signal is a PAL signal, a SECAM signal and an NTSC 4.43 MHz signal, the switches SW1 and SW2 are connected to the terminals C2 and C4 by the microcomputer 68, and the demodulated signal and the NTSC3.
When the signal is 58 MHz, switches SW1 and SW2
Is connected to the terminals C1 and C3 by the microcomputer 68. As a result, video signals containing color components are output from the trap circuits 56 and 58, and the filters 60 and 6
2 outputs an audio signal. The video signal is the switch S
PAL / NTS included in the color demodulation circuit 63 via W3
C demodulator 64 and SECAM demodulator 66. When the switch SW3 is connected to the terminal C5, the video signal output from the VTR (not shown)
AL / NTSC demodulator 64 and SECAM demodulator 66
Given to.

The PAL / NTSC demodulator 64 changes the demodulation mode according to the mode switching signal from the microcomputer 68.
Set to demodulation mode or NTSC demodulation mode. PA
The L / NTSC demodulator 64 receives the 4.43 MHz oscillation frequency signal from the crystal oscillator 70 when the switch SW4 is connected to the terminal C8, and color-demodulates the PAL signal or the NTSC 4.43 MHz signal according to the setting mode. The PAL / NTSC demodulator 64 has a mode set to the NTSC demodulation mode and a switch SW.
4 is connected to the terminal C7, a 3.58 MHz oscillation frequency signal is received from the crystal oscillator 72, and NT
SC 3.58 MHz signal is color demodulated. Meanwhile, SECA
The M demodulator 66 color-demodulates the SECAM signal when the switch SW4 is connected to the terminal C8. Thus P
AL / NTSC demodulator 64 and SECAM demodulator 66
The color difference signals demodulated at the terminals C9 and C1, respectively.
0, and one of the color difference signals is output according to the connection state of the switch SW5 controlled by the switching signal from the microcomputer 68. The color difference signal output from the switch SW5 is then subjected to matrix processing in the same manner as in the embodiment of FIG. 1, and output from a CRT (not shown).

PAL / NTSC demodulator 64 and SEC
The ACC killer circuit 64a and the ID killer circuit 66a included in each of the AM demodulators 66 operate as follows. When the switch SW4 is connected to the terminal C8, a video signal other than the SECAM signal is output to the SECAM demodulator 66.
, The ID killer circuit 66a determines that the video signal cannot be demodulated based on the color burst signal. Then, the ID killer circuit 66a removes the color components included in the video signal and outputs a low-level (“0”) SECAM killer signal. SEC
A signal containing no color component is output from the AM demodulator 66. When the SECAM demodulator 66 receives the SECAM signal, the ID killer circuit 66a does not operate, and the ID killer circuit 66a outputs a high-level ("1") SECAM killer signal. The SECAM demodulator 66 outputs a color difference signal. On the other hand, when PAL / NTSC demodulator 64 receives a signal corresponding to the set demodulation mode and the input oscillation frequency signal, ACC killer 64a does not operate, and a high-level 87 killer signal is output. The PAL / NTSC demodulator 64 outputs a color difference signal. When PAL / NTSC demodulator 64 receives a signal that does not correspond to its setting mode and oscillation frequency signal, A
The CC killer circuit 64a removes the color component of the signal and outputs a low-level 87 killer signal. PAL
A signal containing no color component is output from the / NTSC demodulator 64.

The microcomputer 68 is described in detail in FIGS.
The processing is performed according to the flow shown in FIG. That is, the switch SW5 is connected to the terminal C9 in step S1, and the counter 68a is initialized in step S3. Subsequently, in step S5, the hold of the switch SW1 is released, and in step S7, it is determined whether the switch SW3 is connected to the terminal C5. If "NO" here, it is determined whether the switch SW1 is held in step S9. If "YES" in the steps S7 and S9, the process directly proceeds to the step S15. If "NO" in the step S9, the switch SW1 is connected to the terminal C2 in a step S11, and the process proceeds to the step S15. In step S15, the switch SW4 is connected to the terminal C8. Next, in step S17, the PAL / NTSC demodulator 64 is set to PA
Set to L demodulation mode and wait for 40 ms.

Thereafter, in step S19, it is determined whether the 87 killer signal is at a high level. If "YES", it is determined again in step S21 whether the 87 killer signal is at a high level. If "NO" here, the counter 68a is initialized in step S27, and the process returns to step S19. If "YES", the process proceeds to step S27.
23, the switch SW2 is connected to the terminal C4,
At 25, the hold of the switch SW1 is released, and thereafter, the process returns to step S21. Thus, steps S19 and S
After determining "YES" in 21, the connection of the switch SW2 is switched, and the connection state of the switches SW1, SW2 and SW5 is determined. That is, the color system is determined to be PAL. As a result, even if the video signal is disturbed due to a change in the reception status, the audio is not immediately switched to another channel.

If "NO" in the step S19, it is determined whether or not the SECAM killer signal is at a high level in a step S27. Here, if “YES”, the process proceeds to step S
The switch SW5 is set to the terminal C10 at 29, and then it is determined at step S31 whether the 87 killer signal is once at a high level. If "YES", the process proceeds to step S1.
In step S1, the switch SW5 is connected to the terminal C9.
5, but if “NO”, SE is determined in the step S33.
It is determined again whether the CAM killer signal is at a high level. If "NO", the counter is initialized in step S39 and the process returns to step S27, but "YES".
If so, the switch SW2 is connected to the terminal C4 in step S35.
, And release the hold of the switch SW1 in step S37, and return to step S31. As described above, if one of the ACC killer circuit 64a and the ID killer circuit 66a malfunctions by determining whether or not the 87 killer signal is at the high level in step S31, the PAL demodulation mode is prioritized. Steps S31 to S37
Is established, the connection state of the switches SW1, SW2 and SW5 is determined, and the color system is set to SECA.
Set to M.

If "NO" in the step S27, it is determined whether or not the switch SW5 is connected to the terminal C10 in a step S41. If "NO", the process directly shifts to the step S45, but "YES" is determined. If there is, the switch SW5 is connected to the terminal C9 in step S43, and then the process proceeds to step S45. In step S45, PAL / N
Set the TSC demodulator 64 to the NTSC demodulation mode and
Wait 0 ms. Subsequent steps S47 to S55
Is the same process as in steps S19 to S27 described above, and a duplicate description will be omitted. Steps S49-
By looping S53, switches SW1, S
The connection state of W2 and SW5 is determined, and the color system is N
Determine TSC 4.43 MHz. If "NO" in the step S47, it is determined whether or not the count value of the counter 68a is "4" in a step S57. If "NO", the counter 68a is incremented in a step S59 and the process returns to the step S7. If "YES", the counter 68a is initialized in a step S61. This allows PAL, SECAM and NTSC 4.43MH
The search for z is repeated four times.

When the processing in step S61 is completed, it is next determined in step S63 whether the switch SW3 is connected to the terminal C5. If "NO" here, it is determined whether the switch SW1 is held in step S65. In steps S63 and S65, “YE
If "S", the process directly proceeds to step S69, but if "NO" in step S65, the process proceeds to step S69 after connecting the switch SW2 to the terminal C3 in step S67. C
7 and then, in step S71, sets the PAL / NTSC demodulator 64 to the NTSC demodulation mode and waits for 40 milliseconds. Subsequent steps S73 to S81 are the same as steps S19 to S27, except that the switch SW2 is connected to the terminal C3 in step S77, and thus redundant description will be omitted. Note that the connection state of the switches SW1, SW2 and SW5 is determined by looping steps S75 to S79, and the color system is set to NTSC3.
Confirm at 58 MHz. If "NO" in the step S73, it is determined whether or not the switch SW3 is connected to the terminal C5 in a step S83. If "YES", the process returns to the step S7.
It is determined whether the count value of the counter 68a is "4". If "NO", the counter 68 is incremented in a step S87, and the process returns to the step S63. As a result, the NTSC 3.58 MHz search is repeated four times.

If "YES" in the step S85, it is determined whether or not a synchronization signal is included in the input signal in a step S89, and if "NO", it is determined that the input signal is not a video signal and the process shifts to a step S93. On the other hand, if “YES” in the step S89, it is determined whether or not the vertical frequency of the synchronization signal is 60 Hz in a step S91, and “N” is determined.
If "O", the process proceeds to step S93 assuming that the broadcast is a 50 Hz monochrome broadcast, and if "YES", the process proceeds to step S101 assuming that the broadcast is a 60 Hz monochrome broadcast.In step S93, the switch SW1 is connected to the terminal C2. Then, the switch SW1 is held in step S95, the counter 68a is initialized in step S97, the switch SW2 is connected to the terminal C4 in step S99, and the process returns to step S7. Connect to terminal C1, and then go to step S103
Holds the switch SW1. Then, step S
In step 105, the counter 68a is initialized, and in step S107
To connect the switch SW2 to the terminal C3 and return to step S7. As a result, the black and white video signal is
When output from 6 or 58, the signal from the PAL / NTSC demodulator 64 set to the NTSC demodulation mode is supplied to the CRT.

The tuner 46 is, for example, NTSC 3.58
When a MHz signal is selected, the microcomputer 68 performs processing as described below. That is, first, the switches SW5 and SW1 are connected to the terminals C9 and C2, respectively, and then the switch SW4 is connected to the terminal C8.
The signal is supplied to the ECAM demodulator 66a. Then PAL / NTS
The C demodulator 64 is set to the PAL demodulation mode, and the 87 killer signal output from the ACC killer circuit 64a is determined. At this time, since the 87 killer signal is at a low level,
The microcomputer 68 then determines the SECAM killer signal output from the color killer circuit 66a. This time also SE
Since the CAM killer signal is at the low level, the microcomputer sets the PAL / NTSC demodulator 64 to the NTSC demodulation mode. However, since the oscillation frequency input at this time is 4.43 MHz, it does not match the modulation frequency of the input signal, and the 87 killer signal is at a low level. Therefore, the microcomputer 68 repeats the above process four times, and then connects the switch SW4 to the terminal C7 to output the 3.58 MHz oscillation frequency signal to the PAL / NTSC demodulator 64 and SE.
The signal is supplied to the CAM demodulator 66 and the PAL / NTSC
The demodulator 64 is set to the NTSC demodulation mode. At this time, since the 87 killer signal becomes high level, the microcomputer 68 connects the switch SW2 to the filter 60 and
The audio signal included in the C3.5 MHz signal is extracted. Since the switch SW5 is connected to the terminal C9,
A color difference signal subjected to color demodulation is output from the switch SW5, and an image based on the color difference signal is output from a CRT (not shown).

As described above, the color system is sequentially searched according to the programmed operation, and the system of the input signal is automatically determined. Therefore, the operation may be changed or the program may be changed. In other words, it is not necessary to change the IC in order to change the operation, so if an EPROM or a one-time microcomputer is used, the operation after the change can be confirmed much faster than in the past.

In this embodiment, when both the SECAM killer signal and the 87 killer signal are at a high level, the PAL demodulation mode is prioritized. In this embodiment, the priority order can be easily changed. Further SE
In an area without a CAM system or in a usage method, a search for SECAM may be detected on a program. in this way,
By rewriting the program according to the region to be used and the needs, it is possible to flexibly and quickly develop an optimum color system automatic discrimination system.

Further, in this embodiment, the microcomputer 68 selects one of the trap circuits 56 and 58 in accordance with the killer signal, so that the PAL / NTSC demodulator 64 or the SECAM demodulator 66 performs color demodulation of the video signal. Can be prevented from being affected by the audio signal. In these embodiments, the case where the color demodulation circuit is used in a television receiver has been described. However, it goes without saying that this color demodulation circuit can be applied to a video signal processing circuit such as a VTR or a personal computer.

In these embodiments, the operation of the demodulation circuit is controlled by the microcomputer. However, the present invention is not limited to this.
The operation of the color demodulation circuit may be controlled by a sequence circuit provided outside the color demodulation circuit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart showing main operations of the embodiment.

FIG. 3 is a block diagram showing a conventional technique.

FIG. 4 is a block diagram showing a part of another embodiment of the present invention.

FIG. 5 is a block diagram showing a part of another embodiment of the present invention.

FIG. 6 is a waveform chart showing characteristics of a SAW filter.

FIG. 7 is an illustrative view showing a spectrum characteristic of each TV broadcast system;

FIG. 8 is a flowchart showing a part of the operation of the embodiment in FIG. 5;

FIG. 9 is a flowchart showing a part of the operation of the embodiment in FIG. 5;

FIG. 10 is a flowchart showing a part of the operation of the embodiment in FIG. 5;

FIG. 11 is a flowchart showing a part of the operation of the embodiment in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Television receiver 12 ... Color demodulation device 14, 63 ... Color demodulation circuit 16 ... Microcomputer 18 ... PAL demodulator 20 ... SECAM demodulator 22 ... NTSC demodulator 24, 28 ... ACC killer circuit 26 ... ID killer circuit 32 ... Switch 34 Matrix circuit 36 Memory 38 CRT / drive amplifier 40 CRT 42 Y signal processing circuit 50, 56, 58 Trap circuit 64 PAL / NTSC demodulator 66 SECAM demodulator 64a, 66a Color killer circuit 68 ... microcomputer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 9/00-9/89

Claims (6)

(57) [Claims] 1. A plurality of TV broadcasting systems individually corresponding to a plurality of TV broadcasting systems.
Input means for inputting any one of the broadcast signals, and a color demodulation method corresponding to each of the plurality of TV broadcast methods.
Adopting and color demodulating the input broadcast signal by the input means
Multiple colors to output demodulation enable / disable signal indicating whether
Demodulation means, filter means for extracting an audio signal from the input broadcast signal
And a plurality of demodulation enable / disable signals output from the plurality of color demodulation means.
Discriminating means for selectively taking in a signal and discriminating its state,
And the same demodulation enable / disable signal state can be demodulated continuously multiple times.
Extraction frequency corresponding to the demodulation enable / disable signal when the
Comprising setting means for setting a wave number to the filter means,
Broadcast signal processing device. 2. A demodulation availability determined by the determination means.
The color demodulated signal that has been color demodulated by the color demodulator that outputs the signal
Further comprising selection means for selecting as an output signal.
Item 2. The broadcast signal processing device according to Item 1. 3. The method according to claim 2, wherein the plurality of broadcast signals are PAL, SE,
Whether to follow at least one of CAM and NTSC
The first broadcast signal having a color subcarrier frequency of 4.43 MHz
And the color subcarrier frequency according to the NTSC system and
And a second broadcast signal of 3.58 MHz.
Or the broadcast signal processing apparatus according to 2. 4. The setting means according to claim 1 , wherein said input broadcast signal is
When it is the first broadcast signal, 5.5 MHz
And the input broadcast signal is the second broadcast signal.
Set 4.5 MHz to the filter means,
The broadcast signal processing device according to claim 2. 5. A broadcast according to claim 1, wherein :
Comprising a signal processing apparatus, a television job down receiver. 6. A broadcast according to any one of claims 1 to 4.
A VTR including a signal processing device.