JPH09233480A - Multi-system color tv receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve control defenition and accuracy by preventing a reference signal from being affected by the component and defenition of a composite video signal and to complete automatic control through one system. SOLUTION: A reference signal 17 depending on no system is generated by a reference signal generating circuit 11 and corresponding to this signal, a signal 18 depending on systems is generated from a 2nd reference signal generating circuit 12. The signal 17 is supplied to the reference signal generating circuit 12 and a 2nd automatic control circuit 10. At the automatic control circuit 10, a time constant for setting the characteristics of a filter is detected, and information to be corrected or controlled is outputted. At the reference signal generating circuit 12, the color sub-carrier frequency signals of respective chroma systems are selectively generated. Which frequency is to be generated depends on a switching signal from a system discrimination circuit 24. The signal from the reference signal generating circuit 12 is supplied to a 1st automatic control circuit 9 and a chroma signal processing circuit 6. The convergent point of the automatic control circuit 9 is transited corresponding to the change of the signal 18, the time constant is detected with the signal 18 as a reference and a control signal is outputted so as to provide desired characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
(Television) Multi-system color TV capable of viewing signals
Regarding the receiver.

[0002]

2. Description of the Related Art Currently, PAL / SECAM / N is used in the world.
TSC has three color TV broadcasts, and in a certain area, a plurality of systems can be viewed. Color TV capable of receiving multiple types of TV signals for such areas
The receiver has been put to practical use. PAL and NTSC system,
Both transmit chroma signals by AM modulation, but the subcarrier frequency is 4.433619M in the PAL system.
Hz and NTSC system differ from 3.579545 MHz. On the other hand, the SECAM method employs FM modulation. The color subcarrier frequency is different for each line,
4.25MHz on line, 4.4062 on RY line
5 MHz.

A multi-system compatible TV receiver is required to support these frequencies and has a function of switching the characteristics of each processing circuit and the AM / FM demodulation circuit. In recent years, most of the peripheral components and circuits that operate based on the time constant, such as filters and delay lines necessary for processing composite video signals,
It tends to be built into the C, and the switching operation accompanying it tends to be complicated.

A conventional video signal processing unit will be described with reference to FIG. A composite video signal detected by a tuner circuit (not shown) is input to the input terminal 13. The composite video signal is input to the chromatolap circuit 1, the chroma band pass filter (BPF) 2 and the synchronization signal processing circuit 7, respectively. The chromatographic circuit 1 removes the chroma signal and outputs the luminance signal component to the delay line 3. The delay line 3 delays the luminance signal for a predetermined time and outputs the luminance signal to the aperture control circuit 4. The aperture control circuit 4 operates the sharpness of the luminance signal. This output signal is input to the video signal processing circuit 5 and subjected to normal control such as contrast control and output to the luminance signal output terminal 14.

On the other hand, the chroma BPF 2 extracts only the chroma signal from the composite video signal and outputs the chroma signal to the chroma signal processing circuit 6. In the chroma signal processing circuit 6, the VCX
The oscillation signal 45 from the O44 and the discrimination output signal from the system discrimination circuit 24 are input, and the chroma signal is demodulated by the discriminated system. The chroma signal processing circuit 6 has other functions such as a killer detection function and a color control function, and the result of the killer detection is output to the system discrimination circuit 24. The demodulated color difference signal is output to the color difference LPF8. The LPF 8 removes the unnecessary band signal and outputs the color difference signal to the output terminal 15. The sync signal processing unit 7 extracts the composite sync signal from the composite video signal, performs horizontal and vertical deflection processing, and outputs the deflection signal to the output terminal 16. Note that the number of output terminals 15 and 16 is not one in practice, but a plurality of output terminals, but the description here is omitted to simplify the description.

The oscillation signal 45 of the VCXO 44 is supplied not only to the chroma signal processing but also to the first automatic adjustment circuit 42. The first automatic adjustment circuit 42 detects with the oscillation signal 45 as a reference that the time constant of each filter is a predetermined value. The detected correction or control signal is output to the frequency control terminal of the chromatographic wrap circuit 1 and the chroma BPF 2. The synchronization signal processing circuit 7 has a horizontal oscillation circuit, and outputs its oscillation signal 46 to the second automatic adjustment circuit 43. Similarly, the second automatic adjustment circuit 43 also detects whether the time constant is a predetermined value. The detected correction or control signal is applied to the delay line 3, the aperture control circuit 4 and the color difference LPF 8.
Output to the frequency control terminal of.

A system for adjusting time constants of filters in a multi-mode TV receiver will be described below. First, we will describe a general-purpose PAL / NTSC two-system compatible system.
The case of supporting the SECAM method will be described next.

It is necessary to switch the center frequencies of the chromatolap circuit 1 and the chroma BPF 2 depending on which system the incoming composite video signal is. The process will be described. Now, it is assumed that the VCXO 44 oscillates at the PAL system color subcarrier frequency. The system discriminating circuit 24 monitors the outputs of the PAL and NTSC system killer detection circuits in the chroma signal processing circuit 6, and when both discriminate to be black and white, the oscillation frequency of the VCXO 44 is set to the NTSC system frequency after a predetermined time. Switch to. In this case as well, the outputs of both killer detection circuits are monitored, and if the NTSC system killer circuit determines that the color is detected, the VCXO44
Keep the oscillation frequency of. Further, it outputs a control signal in the NTSC system color state to the chroma signal processing circuit 6 to activate the NTSC system demodulation circuit. Conversely, when the VCXO 44 is at the PAL frequency, PAL
When it is determined that the system killer circuit is in color, the system determination circuit 24 holds the frequency of the VCXO 44 as it is and outputs a control signal for activating the PAL system demodulation circuit to the chroma signal processing circuit 6. The first automatic adjustment circuit 42 corrects or controls the time constant of the filter, that is, the center frequency with reference to the oscillation signal of the VCXO 44. When the frequency of the VCXO 44 changes, the center frequency of the filter changes in response thereto, so that if the frequency of the VCXO 44 is held in the desired system reception state, it automatically converges to the desired center frequency.

Since the chrominance signal demodulated by the chroma signal processing circuit 6 contains many harmonic components of the carrier wave, only the low-frequency chrominance signal is removed and the chrominance LPF 8 is extracted.
Through. Since the band of the color difference signal is generally limited to about 800 KHz, the LPF characteristic is determined in that band, and it is usually possible to sufficiently suppress the harmonic frequency of the carrier. Since it does not remove a certain fixed frequency unlike the trap circuit, the characteristics are not switched according to the system discrimination result such as PAL / NTSC.

Since the frequency of the chroma signal changes depending on the system, it is necessary to switch the characteristics corresponding to it.
There is no difference between PAL and NTSC in the luminance signal.
Strictly speaking, even in the PAL and NTSC systems, it is based on the black and white standard system that was originally adopted (expressed by one letter of B, G, D, K. Japan is M). In some cases, the band per channel differs. In other words, since the band of the luminance signal is different, the processing band should be changed originally, but the system cannot be actually detected and switching is not performed. Therefore, in this description, it is assumed that the luminance signal does not depend on the method.

As a filter circuit in the luminance signal processing, there is a delay line or aperture control. In both cases, an all-pass filter (APF) is used as a basic cell. As described above, in the chroma signal path, the chroma BPF2 and the color difference LPF8 are used.
, The color difference signal is output with a delay accordingly. On the other hand, when the luminance signal is advanced on the time axis, the color shifts on the screen and is placed on the luminance, which is unsightly. Therefore, the delay line 3 is used to delay the luminance signal to align the position on the screen. The delay time of the chroma path does not change much depending on the method. The LPF8 that occupies most of the delay time is a fixed delay, and the group delay of the chroma BPF2 is also less affected by the switching of the center frequency.

Therefore, even if the system is changed to PAL / NTSC, the delay time of the delay line is not switched and used in a fixed manner. The same applies to the aperture control circuit 4. The aperture control circuit 4 changes the sharpness of the signal, and controls software and sharpness. In this control, a delay line is mainly used, and a predetermined frequency determined by the group delay time of the delay line is amplified or attenuated to obtain an effect on the screen. This effect is only the quality of brightness, and is determined independently of the chroma system such as PAL / NTSC. Small-inch TV as a rule
Around 2.4MHz for large-inch TVs at 4MHz
In the vicinity, the frequency at which aperture control is performed has also changed depending on the size of the screen.

As for the delay line 3 of the luminance signal system, the aperture control circuit 4, and the color difference LPF 8 of the chroma system, it is desirable that the performance setting does not depend on the chroma system as described above. But,
If the time constants of these filters are not adjusted, characteristic fluctuations will increase due to variations, so automatic adjustment is necessary.
The reference signal to be used for this is a signal that does not depend on the chroma system, but the signal of the VCXO 44 cannot be used because it changes depending on the system. When the synchronization signal processing circuit 7 is compatible with multiple systems, it depends on the monochrome standard system instead of the chroma system. Looking at the synchronous system, the standard systems in the world are 262.5 lines / 60 Hz horizontal / vertical (domestic) and 312.
There are only 2 systems of 5 lines / 50 Hz. In terms of horizontal frequency, the former is approximately 15.734 KHz and the latter is 15.62.
The difference is about 5% from 5 KHz. This horizontal frequency is used as a reference signal for a circuit that does not depend on the chroma system. Horizontal oscillation signal in synchronization signal processing (usually 32 times = 500K
(Hz) is input to the second automatic adjustment circuit 43, and if this signal is used to adjust the circuit independent of each chroma system, PAL
A substantially constant characteristic can be obtained regardless of which type of signal, / NTSC, arrives.

The case corresponding to the SECAM system will be described below. Since the SECAM system signal is FM-modulated, the demodulation circuit itself is completely independent from that of PAL or NTSC, and the processing system is also different. Since the SECAM chroma signal passes through a filter (standard) called an inverse bell filter on the transmitting side, a bell filter for restoring this is necessary when receiving. As a practical example, there are a case where a bell filter is used independently of the chroma BPF and a case where the bell filter also serves as the BPF. Therefore, the chroma BPF 2 is used as a representative, and the chroma signal processing circuit 6 uses S.
All circuits other than the bell filter required for ECAM demodulation processing are included.

The PAL or NTSC system may be different from the modulation system in some cases, but the system determination circuit 24 determines the determination priority order because the combination in the area where multi-system reception is possible is known. For example, when the killer detection circuit of each system malfunctions, particularly when it is determined that a plurality of detection circuits are color, the system determination circuit is set to receive by a system having a predetermined high priority. Otherwise, a plurality of plural circuits operate simultaneously and a desired color difference demodulation signal cannot be obtained. Generally, the PAL system has the highest priority. Even when SECAM is received, it is necessary to always detect whether or not it is the PAL system. When receiving the SECAM system, VC
Since XO44 is not necessary, there is no problem for SECAM demodulation regardless of which frequency PAL / NTSC is oscillating, but the PAL method is fixed in order to operate PAL detection.

The SECAM system chroma subcarrier frequency is
As mentioned above, since it is close to the frequency of the PAL system chroma signal,
The first automatic adjustment circuit 42 may continue the same operation as at the time of PAL. The system discrimination circuit 24 is SECA
By fixing the VCXO44 to the PAL system frequency at the time of M, even in SECAM, the chromatographic circuit 1 and BPF
2 works well.

By arranging the reference signal and the automatic adjustment circuit as described above, it is possible to configure a multi-system TV receiver capable of excellent reception when a multi-system TV signal arrives.

However, since the reference signal supplied to the circuit, which is preferably independent of the method, depends on the synchronization signal such as 50/60 Hz, the convergence point of the automatic adjustment circuit varies depending on the quality of the synchronization signal, and the characteristics of the circuit to be adjusted. Fluctuates. Further, the adjustment convergence point also changes depending on the synchronization frequency, so that there is a problem that the characteristics change when a non-standard system signal arrives.

When the VCXO frequency is switched in the automatic adjustment circuit, the convergence point of the automatic adjustment circuit is changed with respect to the switched frequency. Therefore, it takes time to reach a new convergence point, which is desirable. There is a problem that the image is not stable until the characteristics are obtained. Furthermore, two systems of automatic adjustment circuits are required, which causes an increase in the cost of the adjustment circuits.

[0020]

In the above-mentioned conventional multi-system color TV receiver, the reference signal supplied to the circuit group, which is preferably independent of the system, is the component of the composite video signal such as the synchronizing signal or the chroma signal and its component. It was affected by the quality and required two adjustment circuits.

The present invention improves the adjustment quality and accuracy by preventing the reference signal from being affected by the component of the composite video signal and its quality, and at the same time, the multi-system color TV reception in which the automatic adjustment is completed by one system. Machine.

[0022]

In order to solve the above-mentioned problems, in the multi-system color TV receiver of the present invention, each T
A circuit in which a first reference signal that does not depend on the V method is prepared, and a second reference signal that depends on the method is generated from the reference signal, and it is desirable that the first reference signal does not depend on the method Supply to the flock.

As a result, one reference signal that is completely independent of each TV system can be obtained, which is completely different from the conventional circuit arrangement. Therefore, if this is adjusted as a reference signal, there is no problem of adjustment quality or accuracy. Since there are two, a reference that depends on the method and a reference signal that does not depend on the method, if the signal is supplied as a reference signal to the automatic adjustment circuit of the circuit group that should not depend on the method even in the conventional system, the sync signal quality is affected. Adjustments can be made without

In addition, the first reference signal that does not depend on each TV system is prepared, and only the system that automatically adjusts by the reference signal is provided, and the adjustment information is desired for the circuit group that desirably depends on each TV system. Supply through a shift circuit that shifts to the value of.

As a result, the convergence point of the automatic adjustment is determined by the reference signal which does not depend on each TV system, and the adjustment information is directly applied to the circuit group which is preferably independent of the system, and the adjustment information is applied to the circuit group which should be dependent. By shifting and giving, not only one automatic adjustment circuit can be provided, but also the convergence point of the automatic adjustment circuit does not change, so there is no transition time itself due to a change in the convergence point. According to the result of the method discrimination, the characteristic change is completed in real time, and the image is always in a stable state.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a circuit diagram for explaining the first embodiment of the present invention, and the same components in FIG. 7 are designated by the same reference numerals. In this embodiment, again PAL and NTSC
Method 2 system reception is explained, and then SEC
The case of receiving the AM method will be described. First, FIG.
In the circuit (1), separation of the reference signal will be described.

A composite video signal (not shown) detected by the tuner circuit is input to the input terminal 13. The inputted signal is inputted to the chromatolap circuit 1, the chroma BPF 2 and the synchronizing signal processing circuit 7. In the chromatographic lap circuit 1,
The chroma signal of the composite video signal is suppressed and removed, and only the luminance signal is output. The delay line 3 delays the luminance signal for a predetermined time and outputs the luminance signal to the aperture control circuit 4. The aperture control circuit 4 changes the sharpness of the signal. After that, the video signal processing circuit 5 performs contrast control and the like, and then outputs the luminance signal from the output terminal 4.

The chroma BPF 2 extracts and outputs only the chroma signal of the composite video signal. The chroma signal processing circuit 6 performs demodulation and color control to convert the color difference signal to the color difference LPF.
8 is output. The color difference LPF 8 removes the unnecessary signal and outputs only the color difference signal in the required band from the output terminal 15 as the color difference signal. Chroma signal processing circuit 6 and system discrimination circuit 2
4 inputs and outputs signals respectively. The sync signal processing circuit 7 extracts the composite sync signal from the composite video signal, generates a deflection signal from the horizontal and vertical sync signals, and outputs it to the output terminal 1.
6 is output.

The first reference signal generating circuit 11 generates a reference signal 17 having a predetermined frequency. This signal 17
To the second reference signal generating circuit 12 and the second automatic adjusting circuit 10. The second automatic adjustment circuit 10 is supplied with the reference signal 17 which does not depend on the method, detects the time constant for setting the characteristic of the filter, and outputs the information for correction or control. The second reference signal generation circuit 12 selectively generates a color subcarrier frequency signal of each chroma system based on the reference signal 17. Which frequency is generated depends on the switching signal from the system discrimination circuit 24. The output signal 18 of the second reference signal generation circuit is the first automatic adjustment circuit 9 and the chroma signal processing circuit 6.
To supply. Since a signal whose frequency changes depending on the method is applied to the first automatic adjustment circuit 9, its convergence point changes due to a change in the reference signal 18. The time constant is detected with reference to the reference signal 18, and a control signal for obtaining desired characteristics is output.

As described in the conventional example, the chromatographic lap circuit 1 and the chroma BPF 2 need to change their center frequencies depending on the chroma system, so the output of the first automatic adjustment circuit 9 is connected. On the contrary, the delay line 3, the aperture control circuit 4, and the color difference LPF 8 should be provided with the adjustment information independent of the chroma system, and the output of the first automatic adjustment circuit 9 is connected.

Here, a concrete example of the first and second reference signal generating circuits 11 and 12 is a fixed frequency VCXO.
And DDS (Direct Synthesis Digital Synthesizer). Regarding this, reference is made to Japanese Patent Application No. 6-320369, "Oscillation circuit", which was previously filed by the same applicant, and description thereof is omitted here. In this example, the first reference signal is VCXO, but the oscillation frequency is not switched by the chroma system, but is a substantially fixed (variable range is about 200 PPM) frequency. With this accuracy, the effect on the screen is below the detection limit. DD based on this
Although S is used to generate an arbitrary frequency, the frequency is a subcarrier frequency of PAL or NTSC, and either one is generated by a control signal from the system discrimination.

In this embodiment, the crystal precision can be obtained regardless of the precision of the reference signal. Further, a stable reference signal can be obtained irrespective of the reception state and the signal source, so that the quality of the horizontal synchronizing signal is not affected.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the first automatic adjustment circuit 9 of the circuit of FIG. 1 is deleted, and adjustment information is sent from the second automatic adjustment circuit 10 to the chromatolap circuit 1 and the chroma BPF 2 via the first shift circuit 21. It is what is output.

The first shift circuit 21 includes a system discriminating circuit 2
The system adjustment information is input from 4 to the frequency control terminal. Second
Since the automatic adjustment circuit 10 detects and adjusts the time constant by the reference signal that does not depend on the method, once the adjustment converges, the convergence point does not change. However, since the chromatographic lap circuit 1 and the chroma BPF 2 need to operate at the center frequency depending on the chroma system, the output of the second automatic adjustment circuit 10 is shifted by a predetermined value and applied. As an example, if the frequency of the reference signal 17 is 4 MHz, and the control signal from the system discrimination circuit 24 indicates PAL, then 4.433619 / 4 = 1.108 (times) (1) If it is, the shift is performed at a ratio of 3.579545 / 4 = 0.895 (times) (2).

When the adjustment information output from the second automatic adjustment circuit 10 is a current, this first shift circuit 21
By shifting to the above ratio, the center frequencies of the chromatographic wrap circuit 1 and the chroma BPF 2 become the subcarrier frequencies of the respective colors. Since only the chromatolap circuit 1 and the chroma BPF 2 are shifted in frequency, the other delay lines 3 and the aperture control circuit 4 are controlled by the second automatic adjustment circuit 10 as they are, and the frequency characteristic fluctuates. do not do.

Since the transition time of this embodiment is on the order of nsec, it is possible to switch in real time, and it is possible to prevent a change in transient response from appearing on the TV screen.

Using the shift function of this embodiment,
More complex control is possible. This will be described with reference to FIG. 3 as a third embodiment of the present invention. In FIG. 3, a part necessary for explanation is taken out from FIG. 2 and an embodiment part is added.

To the second automatic adjustment circuit 10, a reference signal 17 which does not depend on the system is applied as in FIG. The output 20 of the second automatic adjustment circuit 10 is supplied to the delay line 3, the aperture control circuit 3 and the color difference LPF 8 as shown in FIG. 2, and at the same time, the first shift circuit 21 and the newly provided second shift circuit 22.
Also connect. The output of the first shift circuit 21 is connected only to the chromatographic circuit 1, and the output of the second shift circuit 22 is connected to the chroma BPF 2. The output of the system discriminating circuit 24 is input to the shift control circuit 23, and the shift control circuit 23 independently operates the first and second shift circuits 2 respectively.
The shift amounts of 1 and 22 are controlled.

The following table shows the first and second shift circuits 2
The values of the frequencies of the filters controlled by 1 and 22 are shown. Note that 4.433619 MHz is 4.43 MHz, and 3.579545 MHz is 3.58 MHz.

System discrimination result Shift 1 (chromatography lap) Shift 2 (chroma BPF) PAL color 4.43 MHz 4.43 MHz NTSC color 3.58 MHz 3.58 MHz white black 4.43 MHz 3.58 / 4.43 MHz The shift operation is shown in FIG. It is the same concept as that illustrated in. In the case of color reception, the center frequency is shifted to the frequency according to each method. In the case of black and white reception, the chrominance detection circuit switches the frequency generated in the reference signal 2 every predetermined period because the chroma processing system must constantly search for which type of color signal has arrived. Continue to monitor the output of. When the frequency of the chromatographic circuit is switched in synchronization with this, not only the group delay but also the band in which the luminance signal is trimmed changes, so the image quality changes at every predetermined period, and on the actual screen it seems to be a troublesome dancing. . To avoid this, it is fixed to 4.43 MHz in black and white. It may be fixed at 3.58 MHz.

However, the lower the frequency is, the larger the luminance signal energy is in general, and it is considered that it is easier to visually recognize that the energy becomes softer. Therefore, it is preferable to fix the frequency to a higher frequency.

Recently, when a chromatographic filter is built in, it often has a bypass function.
In this case, since the black-and-white trap can be turned off (bypassed), there is no problem even if the chroma system is searching. Even if it has an off function, it is the microcomputer that controls the entire system that actually performs the on / off operation, which is different from the IC that mounts the chromatolap circuit.

Therefore, the system shown in FIG. 3 and Table 1 is considered to be effective as a fail-safe when the control does not have an ON / OFF function of the chromatographic circuit, or when the microcomputer has a control error.

Although the explanation has been made by using the actual circuit group necessary for each signal processing from the system of FIG. 1, it is the chromatographic circuit that requires the most adjustment accuracy among them. In that sense, it is preferable to provide an independent automatic adjusting circuit for adjusting the frequency characteristics of the chromatographic circuit. However, with that, the number of automatic adjustment systems becomes the same as the conventional one, and it becomes impossible to achieve low cost.

FIG. 4 shows a fourth embodiment of the present invention in which the automatic adjustment circuit and the shift function are combined and time-division adjustment is performed to adjust all the filters while keeping the adjustment accuracy of the chromatolap circuit at the best level. 2 is a circuit diagram for explaining the embodiment of FIG. 4 is shown in a modified form from FIG. 3, and the other blocks are the same as those in FIG. 2 and are omitted.

The reference signal 17 not depending on the method from the first reference signal generator 11 is connected to one input terminal of the switch 27, and the composite video signal is input to the other input terminal. The composite video signal is also connected to the chroma BPF 2 and the sync signal processing circuit 7. The switch 27 switches which one is connected with the timing pulse from the timing control circuit 30. The output of the switch 27 is connected to the input of the chromatographic wrap circuit 1, and only the luminance signal is output. The third automatic adjustment circuit 29 inputs the reference signal 17 and the output signal 32 from the chromatographic wrap circuit 1. The phase difference is detected from the two signals 17 and 32, and the adjustment information is supplied to the third shift circuit 28,
Output to the second shift circuit 22 and other filter groups. The shift control circuit 23 inputs the discrimination result and the timing pulse signal from the system discrimination circuit 24, and outputs the frequency shift information to the second and third shift circuits 22 and 28. The third shift circuit 28 shifts the automatic adjustment information by a predetermined value based on the information and outputs it to the chromatolap circuit 1. The second shift circuit 22 operates similarly to FIG.

The timing pulse is set to a predetermined period within the horizontal or vertical blanking period. The switch 27 selects the reference signal 17 in a predetermined period and the signal from the signal 13 in the other periods. Further, as the output signal 32, an internal signal having a 90-degree phase difference from the input at the trap center frequency is extracted.
The frequency of the reference signal 17 is 4 MHz (fref)
Assume that

First, in the blanking period, the reference signal of the reference signal 17 which is independent of the system is supplied to the chromatolap circuit 1,
A signal obtained by shifting the phase of the signal 32 is output. The third automatic adjustment circuit 29 compares the phases of the original signal and the signal 32 and outputs a correction signal to the third shift circuit 28. At this time, the shift value is set to 1 and the trap frequency is set to 4 MHz.
Set to z. FIG. 5B corresponds to this. The third automatic adjustment circuit 29 converges so that the center frequency of the chromatographic circuit 1 is adjusted to 4 MHz. After that, when the timing pulse within the blanking period ends, the input signal path of the chromatographic wrap circuit 1 is switched to the composite video signal side. Further, a control signal for switching from the shift control to the value of the above formula (1) or (2) is output to the third shift circuit 28. If the value of the equation (1) is used, the chromatographic lap frequency becomes 4.43 MHz in the picture period, and the position instantly shifts to the position shown in FIG. 5C. In addition, if the value of the expression (2),
Instantly move to the position (a). Since the automatic adjustment circuit detects the phase difference between the reference signal and the original signal that have actually passed through the chromatographic wrap circuit 1, the chromatographic lap can be adjusted most accurately.

The converged value of the third automatic adjustment circuit 29 does not change regardless of the value of the equation (1) or (2) when the frequency is switched. The switching is performed by the third shift circuit 2
Since 8 is in charge and adjustment is always performed with fref, it is stable regardless of the difference between black and white / method. Since the second shift circuit 22 can be set to the shift operation independent of the third shift circuit 28, the search operation and the holding operation can be favorably controlled even if the automatic adjustment is based on 4 MHz. Since the output of the third automatic adjustment circuit 29 is constant regardless of the method, the delay line 3
Also, it can be supplied as adjustment information for the aperture control circuit 4.

In this embodiment as well, it is possible to set the determination priority in SECAM, and there is no problem in SECAM reception. Set the second reference signal generation circuit 12 to P
It suffices to fix the frequency to the AL frequency, and the circuit group such as the filter has already been adjusted with the reference signal not depending on the system, and thus operates in the same manner as in the past. In terms of priority, PA
Of the three types of killer detection circuits of L / NTSC / SECAM, the SECAM killer circuit is the one that is most likely to malfunction in the other type. Conventionally, various circuits and systems have been devised to deal with this. In this embodiment, a system capable of wiping them can be configured.

In terms of malfunction, SECAM should be the lowest priority. SEC to do this
It is necessary to perform two killer detections of PAL and NTSC systems during AM reception. According to the present invention, all circuits can be adjusted as described in the embodiments of FIGS. 2 and 3 without using any reference signal depending on the method, which can be realized. A search signal can be separately sent from the system discrimination circuit to the second reference signal generation circuit 12 during SECAM reception, and can be operated separately from the frequency setting of the chromatographic wrap circuit 1 and the chroma BPF 2.

Therefore, it is possible to operate both PAL and NTSC killer detection circuits in the back while performing SECAM reception in a stable state. For example, SECAM
Even if the killer circuit malfunctions, if the killer detection circuit of the correct system detects that it is the color signal of its own system, it will switch to the original system without fail, so that the malfunction can be prevented. At this time, the reference signal 17 may be used for the bell filter automatic adjustment circuit.

Since the chroma carrier frequency is slightly different from that of PAL when SECAM is received, according to the present invention, S
Processing unique to ECAM can be added. Chroma B
This is a method in which the shift of PF2 is made slightly lower than that of PAL, and the chromatographic wrap circuit 1 is made the same. Since the carrier frequency of the SECAM method is as described above, if the frequency is set to be exactly the same as that of PAL, the chromatographic circuit 1 cannot remove chroma components of low frequency. Since the carrier energy has the largest energy, it can be improved by lowering the center frequency of the trap to, for example, the middle of two carriers.

Further, by obtaining the reference signal 17, not only the luminance chroma system filter but also the oscillation circuit can be adjusted. This is made possible by the fifth embodiment of the present invention shown in FIG. 6, and this embodiment will be described below.

This is a horizontal oscillation system portion of the synchronization signal processing circuit 7. The composite sync signal separated by the sync separation circuit 35 is input to the AFC circuit 36 which is a phase comparator. The output of the AFC circuit 36 is output to a VCO (voltage controlled oscillator) 37 to control the oscillation frequency of the VCO 37. The output of the VCO 37 is supplied to the fourth automatic adjustment circuit 39 and the H countdown circuit 38 composed of a frequency dividing circuit. The signal 41 divided by the countdown circuit 38 into a predetermined frequency and phase is AF
The signal is fed back to the C circuit 36 to form a PLL. Other various timing pulse signals are output to each processing unit such as luminance chroma. The timing control circuit 30 of FIG. 4 may be obtained from the output of this countdown circuit 38. The fourth automatic adjustment circuit 39 is supplied with the reference signal 17 of the first reference signal generation circuit 11, and the frequency correction or control signal is supplied to the VCO.
37. Normally, the VCO 37 oscillates at a horizontal frequency of 32 times, and the AFC circuit 36 controls so that the horizontal frequency signal divided by the H countdown and the input synchronizing signal are locked.

In this embodiment, since the reference signal independent of the method is obtained, the VCO 37 can be adjusted. If the fourth automatic adjustment circuit 39 controls the reference signal 17 or its frequency-divided signal so that the oscillation frequency of the VCO 37 matches, the oscillation signal of the VCO 37 is adjusted with the accuracy of the first reference signal generation circuit 11. Therefore, the resonator can be deleted.

[0057]

As described above, by using the circuit of the present invention, the reference signal supplied to the circuit group, which is preferably independent of the system, is prevented from being affected by the component of the composite video signal and its quality. It is possible to improve the quality and precision of adjustment and simplify automatic adjustment.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram for explaining a second embodiment of the present invention.

FIG. 3 is a circuit diagram for explaining a third embodiment of the present invention.

FIG. 4 is a circuit diagram for explaining a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram for explaining the operation of FIG. 4.

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

FIG. 7 is a circuit diagram for explaining a signal processing circuit of a conventional multi-system color TV receiver.

[Explanation of symbols]

1 ... Chromatolap circuit, 2 ... Chroma BPF, 3 ... Delay line, 4 ... Aperture control circuit, 5 ... Video processing circuit, 6
Chroma signal processing circuit, 7 Sync signal processing circuit, 8 Color difference LPF, 9 ... First automatic adjustment circuit, 10 ... Second automatic adjustment circuit, 11 ... First reference signal generation circuit, 12 ... Second
Reference signal generating path, 21 ... First shift circuit, 22 ... Second shift circuit, 23 ... Shift control circuit, 24 ... System discriminating circuit, 28 ... Third shift circuit, 29 ... Third automatic adjusting circuit , 30 ... Timing control circuit.

Claims (7)

[Claims] 1. A first generation circuit that generates a first reference signal that does not depend on different chroma signals in each TV system, and a second generation circuit that receives the first reference signal and that corresponds to the different chroma signals. A second generation circuit for generating a reference signal; a first processing circuit that does not require switching of characteristics due to the different chroma signal; and a second processing circuit that requires switching; and the first reference signal input A first self-adjusting circuit for adjusting the characteristic of the first processing circuit and a second automatic adjusting circuit for inputting the second reference signal to adjust the characteristic of the second processing circuit. A multi-system color TV receiver characterized in that 2. A first generation circuit that generates a first reference signal that does not depend on different chroma signals in each TV system, and a second generation circuit that receives the first reference signal and that corresponds to the different chroma signals. A second generation circuit for generating a reference signal; a first processing circuit that does not require switching of characteristics due to the different chroma signal; a second processing circuit that requires switching; and a first processing circuit for inputting the first reference signal. An automatic adjustment circuit that automatically adjusts the characteristics of the first processing circuit, and a shift circuit that adjusts the characteristics of the second processing circuit by shifting the automatic adjustment information corresponding to the different chroma signals. A multi-system color TV receiver characterized in that 3. A first generation circuit that generates a first reference signal that does not depend on different chroma signals in each TV system, and a second generation circuit that receives the first reference signal and that corresponds to the different chroma signals. A second generation circuit that generates a reference signal; a second processing circuit that includes a first processing circuit that does not require characteristic switching due to the different chroma signal; and a second processing circuit that includes a plurality of processing circuit groups that require switching; An automatic adjustment circuit for automatically adjusting the characteristics of the first processing circuit by inputting the reference signal, and the automatic adjustment information to the processing circuit groups of the second processing circuit corresponding to the different chroma signals. A multi-system color TV receiver comprising: a shift circuit that individually shifts and individually adjusts characteristics of a processing circuit group of the second processing circuit. 4. A first generation circuit that generates a first reference signal that does not depend on different chroma signals in each TV system, and a second generation circuit that receives the first reference signal and that corresponds to the different chroma signals. A second generation circuit for generating a reference signal, a first processing circuit and a required second processing circuit that do not require switching of characteristics due to the different chroma signals, and characteristics of the first or second processing circuit An automatic adjustment circuit that adjusts the adjustment information, a shift circuit that shifts the adjustment information corresponding to the different chroma signals, a switching circuit that switches between the first reference signal and the processed signal, and a timing that switches the path of the switching circuit. A signal from the switching circuit is introduced into one of the third generation circuit that generates a signal and the first or second processing circuit, and the response of the processing circuit is detected to detect the automatic adjustment time. Operating the multilingual type color TV receiver is characterized in that given by shifting the adjustment information to the second processing circuit. 5. The processing circuit detected by the automatic adjustment circuit is the second processing circuit.
Of the processing circuit, the shift circuit sets the shift value of the shift circuit to a predetermined value that does not depend on the chroma signal, which is different depending on each TV system, while the switch circuit selects the first reference signal by the timing signal. During the period in which the processing signal is selected, the characteristics of the second processing circuit are adjusted by the output of the shift circuit as a shift value corresponding to the chroma system, and the first adjustment is made by the adjustment information of the automatic adjustment circuit input to the shift circuit. The multi-system color TV receiver according to claim 4, wherein the characteristics of the processing circuit are adjusted. 6. The multi-system color device according to claim 1, wherein the first processing circuit includes one of a luminance delay line, an aperture control circuit, and a color difference LPF. TV receiver. 7. The multi-method color TV according to claim 1, wherein the second processing circuit includes any one of a chromatographic lap circuit, a chroma BPF, and a bell filter. Receiving machine.