JP3520761B2 - Color system discriminator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver (hereinafter referred to as TV) compatible with a multi-color system.
In particular, the present invention relates to a color system discriminating apparatus which prevents a disturbance in synchronization of an image receiving screen during a color system search having different vertical frequencies when a weak electric field or the like is used.

[0002]

2. Description of the Related Art As a conventional color system discriminating device, Japanese Patent Laid-Open No. 6-351024 has been proposed, and an example of a color system discriminating device for checking all color systems by a microcomputer to check a color killer is described. ing. The configuration and operation of Japanese Patent Laid-Open No. 6-351024 will be described with reference to FIG. Microcomputer 401
After setting various methods for the video chroma IC 402 and providing a certain waiting time, the video chroma IC 402
Information about the presence / absence of a color killer signal is received from the system, and when there is no color killer signal, the system is retained to select the system. SECAM decoder IC403 is SEC
When an AM signal is input, it is converted to a PAL signal, and when it is other than the SECAM signal, it is supplied to the video chroma IC 402 through. SECAM decoder IC
Reference numeral 403 supplies information indicating that SECAM is present to the microcomputer 401 when the SECAM signal is input.

[0003]

However, in the above invention, the search of the color system proceeds from the setting of the 50HZ type color system such as PAL and SECAM to the setting of the 60HZ type color system such as PAL60HZ and NTSC or the 60HZ type system. 50 from the color system settings
As the search to the HZ color system progresses, the vertical frequency setting is also performed at the time of search. Therefore, in the case of operation for a signal whose synchronization is unstable such as in a weak electric field, 50 Hz / 60 HZ
When the determination of becomes unstable, there is a problem that the disturbance of synchronization of the image receiving screen becomes noticeable.

[0004]

In order to solve the above problems, a color system discrimination apparatus of the present invention synchronizes a color demodulation circuit for obtaining a Y, U, V signal by performing color demodulation of a video signal and synchronizing from the video signal. A sync separation circuit that detects and separates a signal, and a microcomputer that sets a color system in the color demodulation circuit and sets a sync signal in the sync separation circuit are provided. When shifting to the discrimination check of color systems with different frequencies, the vertical separation setting is held for the sync separation circuit and the switching operation is stopped , and only the chroma frequency and the color demodulation setting are made for the color demodulation circuit. Check the color killer operation and check the color system.
Judgment to the sync separation circuit after the discrimination of the system is completed
By setting the vertical frequency of the color system, it is possible to prevent the disturbance of the synchronization of the image receiving screen at the time of color system search when the signal state in which the synchronization is unstable such as a weak electric field.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention , in the discrimination operation of a color system, when shifting to a discrimination check of a color system having a different vertical frequency, the vertical frequency is not set but only the chroma frequency and the color demodulation are set. By checking the operation, it is configured to prevent the disturbance of the synchronization of the image receiving screen during the color system search in the case of a signal state where the synchronization such as a weak electric field is unstable. , 50
Search from HZ color system to 60HZ color system or 50H from 60HZ color system
When shifting to a check of a color system having a different vertical frequency, such as a search to a Z system color system, the vertical frequency is not set to the sync separation circuit, but the chroma frequency and the color demodulation are set to the color demodulation circuit. By setting only the settings and checking the color killer operation, and holding the synchronization settings until the color system is finalized, the image display screen during the color system search can be used in the case of a signal state where the synchronization is unstable, such as a weak electric field. Prevents synchronization disorder.

As described above, in the discrimination operation of the color system, when shifting to the discrimination check of the color system having a different vertical frequency, the vertical frequency is not set and only the chroma frequency and the color demodulation are set to check the color killer operation. This has the effect of preventing the synchronization disorder of the image receiving screen during color system search when the signal state such as a weak electric field is unstable.

FIG. 1 is a block diagram of an embodiment of the present invention.
3 to FIG. 3 will be described. (Embodiment 1) FIG. 1 is a block diagram of a color system discriminating apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 101 is a color demodulation circuit, reference numeral 102 is a sync separation circuit, and reference numeral 103 is a microcomputer.

The operation of the color system discriminating apparatus constructed as above will be described below. In FIG. 1, a color demodulation circuit 101 receives a video signal as an input, PAL,
Color demodulation for multi-color systems such as SECAM and NTSC is performed, but if the color system settings from the microcomputer 103 do not match the received signal, color killer operation is performed to prevent abnormal colors from sticking to the image receiving screen. Further, this color killer signal is returned to the microcomputer 103. The microcomputer 103 receives the color killer signal from the color demodulation circuit 101. When the color killer signal is present, the color system currently being set does not match the color system of the signal being received, so that another color system is selected. The color demodulation circuit 101 is set, and various color systems are searched until there is no color killer signal. The microcomputer 10
3 sets the vertical frequency of the color system being set to the sync separation circuit 102. The sync separation circuit 102 is
A part of the video signal is received from the color demodulation circuit 101, horizontal and vertical sync signals are taken out and sent to the sync output section.

In a TV or the like of a multi-color system,
In order to automatically determine the color system of the signal being received, the microcomputer 103 first sets the received signal to 50
Information on whether it is HZ or 60 Hz is provided to the sync separation circuit 102.
From 50HZ, PAL and SECAM, 60H
If Z, NTSC 4.43, PAL60HZ, NTSC
3.58 in order for each color system setting to the color demodulation circuit 10
Perform 1 and check if there is a color killer operation. At this time, if the synchronization state is unstable due to a weak electric field or the like, the settings of 60HZ and 50HZ are frequently changed during the color system search, and the image reception screen is disturbed.

In order to avoid the synchronization disorder of the image receiving screen, it is sufficient to hold the vertical synchronization setting of 50 Hz or 60 HZ and stop the switching operation during the color system search operation until the color system is determined. . Therefore, when searching for a color system, the microcomputer 103 does not set the vertical frequency of the color system to be set to the sync separation circuit 102, but only the settings relating to the chroma frequency and the color demodulation.
1 to determine the color system currently being received from the presence / absence of a color killer signal. After the determination is completed, the microcomputer 103 sets the determined vertical frequency setting of the color system in the sync separation circuit 102.

(Embodiment 2) FIG. 2 is a block diagram of a color system discriminating apparatus according to an embodiment of the present invention. In FIG. 2, reference numeral 201 is a color demodulation circuit and reference numeral 20.
2 is a sync separation circuit, and 203 is a microcomputer.

The operation of the color system discriminating apparatus having the above structure will be described below. In FIG. 2, the color demodulation circuit 201 receives a video signal as an input, PAL,
Color demodulation of a multi-color system such as SECAM and NTSC is performed, but if the color system setting from the microcomputer 203 does not match the received signal, the color killer operation is performed to prevent abnormal colors from sticking to the image receiving screen. Also, this color killer signal is returned to the microcomputer 203.

The microcomputer 203 receives the color killer signal from the color demodulation circuit 201. When the color killer signal is present, the color system currently set does not match the color system of the signal being received.
Another color system is set in the color demodulation circuit 201, and various color systems are searched until there is no color killer signal. Further, the microcomputer 203 sets the vertical frequency of the color system being set in the sync separation circuit 202. The sync separation circuit 202 receives a part of the video signal from the color demodulation circuit 201, extracts horizontal and vertical sync signals, and sends them to the sync output unit.

In a multi-color system TV, etc.,
In order to automatically determine the color system of the signal being received, the microcomputer 203 first sets the received signal to 50
Information on whether it is HZ or 60 Hz is provided to the sync separation circuit 202.
From 50HZ, PAL and SECAM, 60H
If Z, NTSC 4.43, PAL60HZ, NTSC
The color demodulation circuit 20 sets each color system setting in the order of 3.58.
Perform 1 and check if there is a color killer operation. At this time, if the synchronization state is unstable due to a weak electric field or the like, the settings of 60HZ and 50HZ are frequently changed during the color system search, and the image reception screen is disturbed.

In order to avoid the synchronization disorder of the image receiving screen, it is sufficient to hold the vertical synchronization setting of 50 Hz or 60 HZ and stop the switching operation during the color system search operation until the color system is determined. . Therefore, when searching for a color system, the microcomputer 203 does not set the vertical frequency of the color system to be set in the sync separation circuit 202, but only sets the chroma frequency and the color demodulation.
1 to determine the color system currently being received from the presence / absence of a color killer signal. After the determination is completed, the microcomputer 203 sets the determined vertical frequency setting of the color system in the sync separation circuit 202.

(Third Embodiment) FIG. 3 is a block diagram of a color system discriminating apparatus according to an embodiment of the present invention. In FIG. 3, reference numeral 301 is a color demodulation circuit, and reference numeral 30.
Reference numeral 2 represents a sync separation circuit, and reference numeral 303 represents a microcomputer.

The operation of the color system discriminating apparatus constructed as above will be described below. In FIG. 3, a color demodulation circuit 301 receives a video signal as an input, PAL,
Color demodulation of multi-color systems such as SECAM and NTSC is performed, but if the color system settings from the microcomputer 303 do not match the received signal, the color killer operation is performed to prevent abnormal colors from sticking to the image receiving screen. Also, this color killer signal is returned to the microcomputer 303.

The microcomputer 303 receives the color killer signal from the color demodulation circuit 301. When the color killer signal is present, the color system currently set does not match the color system of the signal being received.
Another color system is set in the color demodulation circuit 301, and various color systems are searched until there is no color killer signal. Further, the microcomputer 303 sets, for the sync separation circuit 302, the vertical frequency of the color system being set. The sync separation circuit 302 receives a part of the video signal from the color demodulation circuit 301, extracts horizontal and vertical sync signals, and sends them to the sync output unit.

In a TV or the like of a multi-color system,
In order to automatically determine the color system of the signal being received, the microcomputer 303 first sets the received signal to 50
Information on whether it is HZ or 60 Hz is provided to the sync separation circuit 302.
From 50HZ, PAL and SECAM, 60H
If Z, NTSC 4.43, PAL60HZ, NTSC
3.58 in order for each color system setting to the color demodulation circuit 30
Perform 1 and check if there is a color killer operation. At this time, if the synchronization state is unstable due to a weak electric field or the like, during the color system search, the setting of 60HZ and 50HZ is frequently changed, or the horizontal synchronization is lost, so that the image receiving screen is disturbed. In order to avoid the synchronization disorder of the image receiving screen, it is sufficient to hold the vertical and horizontal synchronization settings and stop the switching operation during the color system search operation until the color system is determined. Therefore, when searching the color system, the microcomputer 303 does not perform the vertical frequency setting and the horizontal synchronization setting of the color system to be set on the sync separation circuit 302, but only the settings related to the chroma frequency and the color demodulation. The demodulation circuit 301 is executed to determine the color system currently being received from the presence / absence of a color killer signal. After the determination is completed, the microcomputer 303 sets the determined vertical frequency setting and horizontal synchronization setting of the color system in the sync separation circuit 302.

[0020]

As described above, according to the color system discrimination apparatus of the present invention, in the color system discrimination operation,
When shifting to the discrimination check of color systems with different vertical frequencies, the vertical frequency setting is not performed and only the settings related to chroma frequency and color demodulation are performed to check the color killer signal, and the synchronization of weak electric field is unstable. It is possible to prevent the disturbance of the synchronization of the image receiving screen at the time of the color system search under various signal conditions.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a color system discrimination apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a color system discriminating apparatus according to an embodiment of the present invention.

FIG. 3 is a block configuration diagram of a color system discrimination device according to an embodiment of the present invention.

FIG. 4 is a block configuration diagram of a discrimination circuit in a conventional color system.

[Explanation of symbols]

101 color demodulation circuit 102 sync separation circuit 103 Microcomputer 201 color demodulation circuit 202 Sync separation circuit 203 Microcomputer 302 Synchronous separation circuit 303 Microcomputer 302 Synchronous separation circuit 401 microcomputer 402 Video Chroma IC 403 SECAM IC

Claims (3)

(57) [Claims] 1. In the color system discrimination operation, when shifting to a discrimination check of a color system having a different vertical frequency, the vertical synchronization setting is held and the switching operation is stopped.
Therefore , after setting the chroma frequency and color demodulation settings and checking the color killer, after the color system discrimination is completed
A color system discriminating apparatus which sets a vertical frequency of the discriminated color system. 2. A color demodulation circuit for performing color demodulation of a video signal to obtain Y, U and V signals, a sync separation circuit for detecting and separating a sync signal from the video signal, and a color system setting for the color demodulation circuit. In the color system discrimination operation by the microcomputer, the sync separation circuit is provided with a microcomputer for setting a synchronization signal, and when the process shifts to a discrimination check of color systems having different vertical frequencies, Keep vertical sync settings
To stop the switching operation, by performing the chroma frequency and the color demodulation set only for the color demodulation circuit to check the color killer operation, before, after the determination of the color system is completed
Vertical of the color system determined for the sync separation circuit
A color system discrimination device characterized by setting a frequency . 3. A color demodulation circuit for color-demodulating a video signal to obtain Y, U, V signals, a sync separation circuit for detecting and separating a sync signal from the video signal, and a color system setting for the color demodulation circuit. A synchronization signal is set in the sync separation circuit, and in the color system determination operation by the microcomputer, vertical and horizontal synchronization is performed with respect to the sync separation circuit during all color system search operations. Hold the setting and switch operation
Stop, check the color killer operation carried out chroma frequency and the color demodulation set only for the color demodulation circuit, Kara
-After completing the system identification,
Vertical frequency setting and horizontal of color system
A color system discriminating apparatus characterized in that synchronization is set .