KR0136021B1 - Method of automatically stabilizing switched 3-broadcasting system of television - Google Patents

Abstract

The present invention relates to a television broadcasting system automatic switching stabilization method, a broadcasting method having a first vertical synchronization frequency (PAL-L method) and a second vertical synchronization frequency based on the vertical synchronization frequency of the broadcast signal (NTSC) Method / PAL-M), which automatically sets the PAL-M method having a second vertical synchronization frequency as a reference broadcasting method when the vertical synchronization frequency of the broadcast signal is 60 Hz. And determining a method of a first vertical synchronization frequency and a method of a second vertical synchronization frequency by determining a vertical synchronization frequency of the broadcast signal, when the vertical synchronization frequency corresponds to a second vertical synchronization frequency. Reading the method and determining whether it is an NTSC method or a PAL-M method according to the presence or absence of a color killer signal by applying the read standard broadcasting method, and using the determined broadcasting method as the reference broadcasting room. And resetting the signal; detecting the RFAGC voltage level with respect to its strength (weak signal or no signal level) upon receiving the broadcast signal, and detecting a synchronization signal, wherein the RF AGC voltage level and the synchronization detection signal are detected. In the case of the weak signal or no signal in the switching of the broadcast method is configured to include the step of preventing the continuous switching of the broadcast method for the first synchronous signal frequency is configured to set the PAL-M method as the default (Default) Then, if the vertical synchronization frequency of the broadcast signal is detected and has a second vertical synchronization frequency, the PAL-N method is set. If the vertical synchronization frequency is the first vertical synchronization frequency, the PAL-M method is first used. When the color killer signal is generated, the standard method is changed to NTSC and stored so that the automatic switching of the broadcasting method is performed. If the electric field is weak, or no signal has an arc is stabilized by controlling the maintenance of the PAL-N system on the basis of the level and the synchronization detection signal of the RF AGC voltage is possible.

Description

TV Broadcasting Automatic Switching Stabilization Method

1 is a block diagram showing a television transmission system automatic switching control apparatus according to a conventional example.

FIG. 2 is a flowchart for explaining the operation of the television transmission system automatic switching control device shown in FIG.

3 is a diagram showing the configuration of an apparatus for implementing a television transmission method automatic switching stabilization method according to the present invention.

4 is a flowchart for explaining a television transmission system automatic switching stabilization method according to the present invention.

＊ Description of symbols for main parts of drawings

10: broadcast method detection means 12: system setting means

14: oscillation control means 16: oscillation means

18: storage means 20: color killer detection means

22: system change means 24: main treatment means

70: tuner 72: video processing means

74: AGC voltage detection means 76: broadcasting system stabilization means

The present invention relates to a television transmission method automatic switching stabilization method, and more particularly, PAL-N method, NTSC method and PAL-M method adopted in South America according to the frequency of the vertical synchronization signal of the television broadcast signal is automatically The present invention relates to a television transmission method automatic switching stabilization method so that the automatically switched broadcast method is maintained stably without any effect on the broadcast signal of the weak field.

As is well known, color television broadcasting methods are classified into NTSC, PAL-M, and PAL-N methods according to the vertical synchronization frequency included in the broadcast signal. Among them, NTSC and PAL-M methods are broadcast signals. While the vertical synchronization frequency of is set to 60 Hz, the PAL-N method sets the vertical synchronization frequency of the broadcast signal to 50 Hz. Therefore, when the broadcasting system is moved to another region, the broadcasting system of the television must be reset. The television broadcast signal can be viewed.

Therefore, in the current television, a method of identifying the vertical synchronization frequency of the broadcast signal and setting the television in a transmission method suitable for the broadcast signal in the region is adopted. According to the switching method of the broadcast method, if the vertical sync frequency included in the broadcast signal is detected and the frequency of the detected vertical sync signal is 50 Hz, the PAL-N method is automatically judged as the PAL-N method. It is set to the state that can receive the broadcast signal of, and when the vertical synchronization frequency included in the television broadcast signal is 60Hz, it is determined by NTSC method or PAL-M method. Here, since the vertical synchronization frequency included in the NTSC and PAL-M broadcast signals is the same as 60 Hz, it is necessary to discriminate between the two broadcast methods. Therefore, in order to discriminate between NTSC and PAL-M systems having the same vertical synchronization frequency, when the vertical synchronization frequency of a broadcast signal is determined to be 60 Hz, the broadcast signal is first processed as a PAL-M broadcast signal. In the case of processing the PAL-M system, the NTSC system is adopted when the color killer signal is generated.

However, according to the method of switching the broadcasting method by setting the PAL-M method as the default as described above, when the color killer signal is generated in the PAL-M method processing, the processing is performed by switching to the NTSC method. For example, when the broadcasting system is periodically checked during the processing of the broadcasting signal, including the initial power-on of the television, even in an area to which the NTSC system is applied, it is always switched to the NTSC system based on the PAL-M system. The process is repeatedly performed, and when the switching of the broadcasting method, that is, the color killer signal is generated, the video signal is muted for about 200 ms, thereby causing a disconnection of the screen.

In view of the above, the present applicant distinguishes the PAL-M method and the NTSC / PAL-M method from the patent application No. 94-21340 filed on August 29, 1994 based on the vertical synchronization frequency of the broadcast signal. If the color synchronous signal is generated with the PAL-M method set when the vertical synchronous frequency corresponds to the NTSC / PAL-M method (ie, when the vertical synchronous frequency is 60 Hz), the standard is NTSC. We proposed the automatic switching method of the television broadcasting system, so that the PAL-M system and NTSC system can be switched in a short time.

According to the automatic switching method of the television broadcasting system, for example, in the South American region, the television broadcasting system automatically switches between PAL-N and NTSC / PAL-M three-system broadcasting based on the vertical synchronization frequency of the broadcasting signal. In the case of automatic switching, the PAL-M method is set as the reference broadcast method when the vertical synchronization frequency of the broadcast signal is 60 Hz, and the vertical synchronization frequency of the broadcast signal is determined to determine the PAL-N method and the NTSC / PAL-M method. If the vertical synchronization frequency corresponds to NTSC / PAL-M, the standard broadcasting method is read out and NTSC or PAL-M is applied according to the presence or absence of a color killer signal. It is determined whether the method is a system, resets the determined broadcasting method to the reference broadcasting method, and maintains the NTSC method or the PAL-M method based on the reset reference broadcasting method.

FIG. 1 is a block diagram showing a television broadcasting automatic switching control device, and FIG. 2 is a flowchart for explaining the operation of the television broadcasting automatic switching control device. The PAL-M method is set and buffered as a reference broadcast method when the vertical synchronization frequency included in the PDP is 60 Hz. As the PAL-M method is set to the reference broadcast method, the broadcast mode switching mode is applied as an intermediate frequency signal is applied from the tuner (not shown) to the broadcast method detecting means 10 via the main processing means 24. The broadcast method detecting means 10 determines whether the vertical synchronization frequency of the broadcast signal is 50 Hz or 60 Hz in step 44. As a result of the determination, when the vertical synchronization frequency is 50 Hz, the detection result of the vertical synchronization frequency is applied to the system setting means 12, and the system setting means 12 determines that the vertical synchronization frequency is 50 Hz in step 46. The oscillation control means 14 sets the system according to the PAL-N method, and the oscillation control means 14 controls the oscillator 16 to oscillate a color frequency suitable for the PAL-N method. Since the main processing means 24 is provided to the main processing means 24, the main processing means 24 processes the broadcast reception signal of the television in accordance with the PAL-N method.

On the other hand, if the vertical synchronization frequency of the broadcast signal is determined to be 60 Hz as a result of the determination in step 44, the process proceeds to step 48 and the broadcast method detecting means 10 determines the level according to the vertical synchronization frequency detection of 60 Hz. Low level), and accordingly, the system setting means 12 reads the reference broadcast method (ie, PAL-M) stored in the storage means 18, and accordingly the PAL-M method according to the reference broadcast method. In step 52) or NTSC (step 54), the reference broadcasting method set in step 42 is a PAL-M method, and thus the recognition signal for setting the PAL-M method is applied to the oscillation controller 14. Accordingly, the oscillation control unit 14 controls the oscillation unit 16 so that the color frequency corresponding to the PAL-M method is oscillated and applied to the main processing means 24.

In this case, if the currently received broadcast method is the PAL-M method, the main processing means 24 processes the broadcast signal according to the PAL-M method, but the currently received broadcast signal is set to the reference broadcast method. In the case of the non-PAL-M method, a color killer signal is generated. Accordingly, when the color killer signal is detected by the color killer detection means 20, the process proceeds to step 54 where the system change signal is transmitted from the system change unit 22 to the oscillation control unit. Is applied to (14). The oscillation control unit 14 controls the oscillation unit 16 when the system change signal is input so that the color frequency of the NTSC system is oscillated and applied to the main processing means 24, and the main processing means 24 currently receives. The broadcast signal is processed by NTSC.

As such, when the vertical synchronization frequency of the broadcast signal is 60 Hz, it is determined whether the current reception broadcast method is changed in step 56 to maintain the broadcast method during processing in the PAL-M method or the NTSC method. When a color killer signal is input by the color killer detecting means 20 when switching from the reception of the -M method (step 52) to the NTSC method, or when switching from the reception of the NTSC method (step 53) to the PAL-M method, for example. When the color killer signal is detected from the color killer detection means 20, the system change means 22 changes the reference broadcast method of step 42 to the corresponding broadcast method in step 58 to the storage means 18 in step 58. The oscillation control means 14 is controlled to change the color frequency by the oscillator 16.

In such a state, the system setting means 12 reads out the reference broadcast method that has been changed and stored in the storage means 18 in step 60, and performs the processing described in steps 50-54 in steps 62-66 to present the present method. It is determined whether the method of the broadcast signal corresponds to the reference broadcast method, and based on the determination, the oscillation control unit 14 controls the oscillation unit 16 so that the color frequency is provided to the main processing means 24 by changing. It will be able to maintain an appropriate broadcasting method.

However, according to the above-described automatic switching method of the television broadcasting system, for example, when receiving a PAL-N broadcasting signal of no signal or weak signal, in case of a weak signal, the RF AGC voltage for channel tuning in the tuner is raised to a high level. Since it is set, even if the vertical synchronization frequency is detected at 50 Hz in the step 44, the broadcasting method detecting means 10 outputs the high level and the low level without setting its output level to the low level for reception of the PAL-N method. This is done repeatedly, and the system (i.e., PAL-M / NTSC and PAL-N) continues to change at every level inversion, resulting in instability, and approximately 200 ms of video muting performed at each switching of the broadcast modes. It gets stuck and the screen becomes black.

Accordingly, the present invention has been made in view of the above-described circumstances. For example, when a broadcasting system of 3-system is automatically switched according to the frequency of the vertical synchronization signal in South America, the broadcasting signal of the weak electric field is received when receiving the current PAL-N method. Another object of the present invention is to provide an automatic switching stabilization method for a television broadcasting system to enable stable reception of a PAL-N method based on an RF AGC voltage and a synchronous detection signal even when no signal is detected.

In order to achieve the above object, according to the present invention, a broadcast method having a first vertical synchronization frequency (PAL-N method) and a broadcast method having a second vertical synchronization frequency (NTSC method / Setting a PAL-M method having a second vertical synchronization frequency as a reference broadcasting method when the vertical synchronization frequency of the broadcast signal is 60 Hz to automatically switch the 3-system broadcasting method of the PAL-M method; Determining a vertical synchronization frequency of the broadcast signal to determine a broadcasting method of a first vertical synchronization frequency and a broadcasting method of a second vertical synchronization frequency; when the vertical synchronization frequency corresponds to a second vertical synchronization frequency, the reference broadcast is performed. Reading the method and applying the read standard broadcasting method to determine whether it is the NTSC method or the PAL-M method according to the presence or absence of the color killer signal, and repeating the determined broadcasting method as the standard broadcasting method. In the television broadcasting method automatic switching control method comprising the step of setting, detecting the RF AGC voltage level for the strength (weak signal or no signal level) of the broadcast signal having the first vertical synchronization frequency; In addition, the step of detecting a synchronization signal, and based on the RF AGC voltage level and the synchronization detection signal to prevent the continuous switching of the broadcast method of the first vertical synchronization signal in the case of the weak signal or no signal in the switching of the broadcast method. Provided is a method for stabilizing automatic switching of a television broadcasting system including a step of making it possible.

Preferably, the detection of the RF AGC voltage level is carried out by level switching of the output side of the switching element conducted by a high level RF AGC voltage set for tuning the weak signal during video processing, and continuously switching the broadcasting scheme. The prevention of is performed by level fixing the detection result of the second vertical synchronization frequency by the second switching element when the RF AGC voltage is high level or when no signal is detected.

In the method for stabilizing automatic switching of the television broadcasting method according to the present invention, the PAL-M method is set as a default, and then the vertical synchronization frequency of the broadcast signal is detected and the PAL-N method is set when the first vertical synchronization frequency is detected. On the other hand, if the vertical synchronous frequency is the second vertical synchronous frequency, first switch to the PAL-M method, which is the reference method, and when the color killer signal is generated, change the reference method to the NTSC method and store the automatic switching of the broadcasting method. On the other hand, when the electric field of the broadcast signal is weak or no signal at the time of reception of the PAL-N method, the RF AGC voltage is controlled to maintain the PAL-N method based on the level and the synchronization detection signal.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

3 is a diagram showing the configuration of an apparatus for implementing a television broadcasting method automatic switching stabilization method according to the present invention, 70 is performed by tuning to the broadcast signal received through the antenna (A) provided to the television. A tuner outputs an intermediate frequency (IF) signal for a broadcast signal, and 72 denotes an output and a synchronization signal for processing the video signal of the IF signal provided from the tuner 70 and determining the strength of the received broadcast signal. Is a video processing means for outputting a synchronous detection signal SD, and the video processing means 72 outputs a high level (approximately 7V to 8V) when the broadcast signal is a weak signal (approximately 25 dB or less) or no signal. On the other hand, in the case of the normal signal (40dB or more), a low level (approximately 0V-1V) is output and applied to the tutor 70. The video processing means 72 detects the vertical synchronization signal of the received broadcast signal and outputs a low level RF AGC voltage when the first vertical synchronization frequency is 50 Hz, while the second vertical synchronization frequency is 60 Hz. In this case, the high level RF AGC voltage is output and applied to the broadcasting method detecting means 10 shown in FIG.

In addition, when the RF AGC voltage output from the video processing means 72 is at a high level, 74 is switched to conduct an RF AGC voltage detection for informing the main processing means 24 shown in FIG. A switching element constituting the means, the switching element 74 of which the base is connected to the RF AGC voltage output side of the video processing means 72 via the resistor R1 and the collector through the resistor R2 to the power supply voltage ( 5V), the RF AGC voltage becomes a high level, i.e., it is in a conducting state during weak electric field or no signal, and the main processing means 24 recognizes the change in the voltage level on the collector side.

76 indicates the main control means to prevent system changes in the weak electric field when the collector side level change (i.e., set to a low level) of the switching element 74 is detected in the switching conduction state of the switching element 74. In 24), a high level signal is applied when a weak signal or no signal is applied, and when the broadcasting method (PAL-N method) using the first vertical synchronization frequency is selected, for example, switching of the broadcasting method by the noise component is performed. A second switching element constituting a broadcast stabilization means for preventing, the switching element 76 having a base connected to the main processing means 24, and the collector of which is vertical at 50/60 Hz in the video processing means 72; For example, if the vertical synchronization signal of the currently received broadcast signal is PAL-N type having a first vertical synchronization frequency, the weak electric field or no signal is included in the automatic switching of the PAL-N type. The PAL-N system by which the noise component consists of a switching transistor to prevent the switching in a different way.

Therefore, the television broadcasting automatic switching stabilization method according to the present invention implemented by the apparatus configured as described above is similarly implemented as described with reference to FIGS. 1 and 2, but in step 44 When the vertical synchronization frequency is determined to be 50 Hz and the broadcast signal or the no signal of the weak electric field is input while the PAL-N method is selected, the IF signal of the broadcast signal tuned by the tutor 70 is applied to the video processing means 72. Accordingly, the video processing means 72 sets the RF AGC voltage to a high level in the case of a weak electric field and applies it to the tuner 70 to compensate for the weak electric field broadcast signal at the tuner 70 ( Step 80 and 82 in FIG. 4, in the case of no signal, the low level synchronization detection signal SD is applied to the main processing means 24 according to the detection result of the asynchronous signal (FIG. 4).

84 and 86). Therefore, when the high level signal representing the weak electric field is output from the video processing means 72, the first switching element 74 becomes conductive, and the voltage level on the collector side is low. Since the main processing means 24 recognizes the signal reception or no signal state of the weak electric field, the main processing means 24 outputs a high level to the second switching element 76 (step 88 in FIG. 4).

Therefore, when the PAL-N type broadcast signal is received, for example, when the weak signal or no signal is detected, the vertical synchronization signal output from the video processing means 72, that is, 50 Hz of the PAL-N type is PAL-M /. The level conversion is prevented by the 60 Hz detection result of NTSC system.

On the other hand, when a broadcast signal having a normal signal strength is received, the RF AGC voltage of the video processing means 72 becomes low level and the switching element 74 is in a non-conductive state, in addition to the synchronous detection signal SD. Since the main processing means 24 controls the second switching element 76 to be in a non-conducting state, the main processing means 24 can be maintained at the high level.

As described above, according to the television broadcasting system automatic switching stabilization method according to the present invention, when the PAL-M system is set to the default (Default), the vertical synchronization frequency of the broadcast signal is detected to have a first vertical synchronization frequency If the vertical synchronization frequency is the second vertical synchronization frequency, the PAL-N method is first converted to the PAL-M method, which is the reference method, and when the color killer signal is generated, the reference method is changed to the NTSC method and stored and broadcasted. When the PAL-N method receives a weak or no signal when the PAL-N method is received, the PAL-N method is controlled based on the RF AGC voltage level and the synchronization detection signal. Stabilization will be achieved.

Claims (3)

Based on the vertical synchronization frequency of the broadcast signal, the three-system broadcasting method of the broadcasting method having the first vertical synchronization frequency (PAL-N method) and the broadcasting method having the second vertical synchronization frequency (NTSC method / PAL-M method) In order to automatically switch, setting the PAL-M method having a second vertical synchronization frequency as a reference broadcasting method when the vertical synchronization frequency of the broadcast signal is 60 Hz, and determining the vertical synchronization frequency of the broadcast signal by Determining a method of a vertical synchronization frequency and a second vertical synchronization frequency; when the vertical synchronization frequency corresponds to a second vertical synchronization frequency, the reference broadcasting method is read and the color is applied by reading the reference broadcasting method. A television broadcasting method automatically configured to determine whether it is an NTSC method or a PAL-M method according to the presence of a killer signal, and resetting the determined broadcasting method to the reference broadcasting method; A switching control method comprising the steps of: detecting an RF AGC voltage level for a strength (weak signal or no signal level) upon reception of a broadcast signal of the first synchronization signal frequency, and detecting a synchronization signal; And based on an AGC voltage level and the synchronization detection signal, in the switching of the broadcasting scheme, in the case of the weak signal or the no signal, the continuous switching of the broadcasting scheme for the first synchronization signal frequency is prevented. TV broadcasting automatic switching stabilization method. The method of claim 1, wherein the detection of the RF AGC voltage level is performed by output level switching of a switching element conducted by a high level RF AGC voltage set for tuning of a weak signal during video processing. TV broadcasting automatic switching stabilization method. The method of claim 1, wherein the prevention of continuous switching of the broadcasting scheme is performed by level fixing the detection result of the second vertical synchronization frequency by a second switching element when the RF AGC voltage is high level or when no signal is detected. Television switching system automatic switching stabilization method characterized in that.