KR20000020424A - Method for compensating synchronizing signal in television - Google Patents

Abstract

PURPOSE: A method for compensating a synchronizing signal in a television is provided to display a stable image screen regardless of a receiving state of a broadcast signal by generating a stable pseudo vertical synchronizing signal having a stored frequency. CONSTITUTION: A microcomputer enables a user to receive a broadcast signal(200). A vertical synchronizing signal is separated from the broadcast signal to be applied to the microcomputer(202). The microcomputer detects a frequency of the separated vertical synchronizing signal(204). A microcomputer judges whether a frequency(B) of a stable vertical synchronizing signal is out of a predetermined range in a frequency(A) of a stable vertical synchronizing signal(216). If the frequency(B) is out of the predetermined range compared to the frequency(A), a pseudo vertical synchronizing signal is generated.

Description

METHOD FOR COMPENSATING VERTICAL SYNCHRONIZING SIGNAL IN A TELEVISION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronization signal compensation method in a television. In particular, an unstable vertical synchronization signal of a broadcast signal is detected according to a reception sensitivity state of a reception area to compensate an unstable vertical synchronization signal based on a stored stable vertical synchronization signal. The present invention relates to a synchronization signal compensation method in a television which enables signal processing to always be performed with a stable vertical synchronization signal even in a weak signal.

In general, a television detects the presence of a synchronization signal and detects the presence of a synchronization signal to selectively use a blue back screen in the case of determining that a channel is being broadcast and when there is no synchronization signal. And a synchronization signal separated from the broadcast signal for vertical scanning.

On the other hand, in the case of conventionally detecting the synchronization signal, the synchronization signal (vertical and horizontal synchronization signal) is separated from the applied broadcast signal and used for horizontal / vertical scanning of the monitor, and the pulse of the horizontal synchronization signal is counted and counted. It was determined whether the number of pulses included in the predetermined predetermined range detected the presence of a synchronization signal.

On the other hand, in a typical NTSC (National Television System Committe) broadcast, the synchronization signal, that is, the horizontal synchronization signal has 30 (frames) X 525 (number of scan lines) = 15750 pulses in 1 sec, and the vertical synchronization signal has 60 pulses. Will have

In addition, the differences between the various broadcasting methods include the frequency of the vertical synchronization signal and the scanning player. The frequency of the vertical synchronization signal is 60 Hz in the above-described NTSC system (NTSC-M) and PAL-M system. Although there are 525 lines of horizontal shot, most PAL methods (eg PAL-N, PAL-B, PAL-B, etc. except PAL-M) and SECAM methods (eg SECAM-B, SECAM-D, etc.) ) Uses 50Hz as the vertical sync frequency and has a horizontal scan line of 625 lines.

However, the synchronization signal having the above-described optimal preset range may be slightly increased or deformed due to the noise during the transmission process and the reception sensitivity of the reception area. If the reception sensitivity is poor depending on the reception area, the synchronization signal is received. Since the signal is a weak signal, the vertical synchronization signal that is separately detected is also unstable, which causes a problem that the video screen displayed on the monitor is shaken.

Accordingly, in the present invention, the vertical synchronization signal of the received broadcast signal is separately counted and the frequency is stored in a stable state, and then the frequency of the vertical synchronization signal is counted at a predetermined period, when the frequency is unstable, that is, the stored frequency and When an error occurs between the frequencies of the currently counted vertical sync signals, a method of generating and using a pseudo vertical sync signal of a stored stable frequency is found.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and counts the frequency of a vertical synchronization signal separated from a broadcast signal received from a television, stores a stable frequency, and then Provides a method of compensating for vertical sync signal in a television to prevent the display of the displayed video screen from shaking by generating a self-generating vertical sync signal having a stored stable frequency when an error occurs by counting the frequency and comparing with the stored frequency. It is.

1 is a block diagram of a television employed in accordance with the present invention.

2 is a flowchart illustrating a synchronization signal compensation process in a television according to the present invention;

<Explanation of symbols for main parts of the drawings>

10: key input unit 20: microcomputer

30: tuner portion 40: synchronous separation portion

50: video / audio signal processing unit 60: monitor

70: speaker

According to an aspect of the present invention, there is provided a method for compensating a vertical synchronizing signal in a television, the method for compensating for a weak signal of a vertical synchronizing signal received and processed by the television, comprising: separating and detecting a vertical synchronizing signal from a received broadcast signal; Counting the frequency of the vertically detected vertical sync signal and storing the frequency of the counted vertical sync signal when the frequency of the vertical sync signal matches the frequency of the preset broadcasting scheme; and separating the frequency of the vertical sync signal separately detected and applied in a predetermined period. And counting and generating a pseudo vertical synchronizing signal having a frequency of the stored vertical synchronizing signal when the counted frequency is out of the stored frequency and a predetermined error range.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

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

1 is a block diagram of a television employed in accordance with the present invention, including a key input unit 10, a microcomputer 20, a tuner unit 30, a sync separation unit 40, a video / audio signal processing unit 50, a monitor 60 and a speaker 70.

In this configuration, the key input unit 10 is an input means for performing the operation of the television, and has a plurality of keys for operating the television, and outputs a key signal corresponding to the user's key operation, and is usually remote A key signal corresponding to a key operation is loaded on an infrared carrier using a remote control capable of input, and the television main body demodulates, detects, and amplifies the received infrared carrier and applies it to the microcomputer 20 described later.

The microcomputer 20 controls the overall operation of the television in response to the key signal from the key input unit 10, and a predetermined key signal for channel tuning from the key input unit 10 as can be seen from the description below. In response to a channel tuning key signal and a numeric key signal, a tuning signal (PLL data) for channel tuning is applied to the tuner unit 30, and the video / audio signal processor 50 is controlled to control the tuning channel. The broadcast signal received by the output control to the monitor 60 and the speaker 70.

In addition, the microcomputer 20 counts the number of pulses of the vertical synchronization signal applied from the synchronization separator 40 using an event counter in the microcomputer 20 to determine the vertical synchronization signal separated from the broadcast signal received. If the detected frequency is a stable frequency corresponding to a preset broadcasting method, the vertical synchronization data is stored in the internal memory, and the frequency of the vertical synchronization signal is continuously counted for a predetermined time period, and the predetermined error is compared with the stored vertical synchronization data. When generated, a pseudo vertical sync signal having a frequency corresponding to the stored vertical sync data is generated to control the video / audio signal processor 50.

Meanwhile, the tuner unit 30 is configured to receive and output a broadcast signal of a channel corresponding to a tuning signal for channel tuning from the microcomputer 20 among a plurality of broadcast frequency signals transmitted from the broadcasting system.

The sync separator 40 separates the vertical sync signal from the broadcast signal from the tuner 30 and applies it to the microcomputer 20.

In addition, the video / audio signal processing unit 50 demodulates and detects a broadcast signal from the tuner unit 30 according to the control of the microcomputer 20, and processes the video signal into a displayable video signal and an outputable audio signal, respectively. Output to the 60 and the speaker 70.

Next, the television having the above-described configuration will be described in detail with reference to the flowchart of FIG. 2 attached to the vertical synchronization signal compensation process in the television according to the present invention.

First, the microcomputer 20 applies a tuning signal corresponding to a predetermined key signal for channel tuning of the key input unit 10 to the tuner unit 30 to receive a broadcast signal that is tuned and applied to a channel selected by the user ( Step 200).

Next, the vertical synchronization signal is separated and detected from the broadcast signal received through the tuner unit 30. The synchronization separation unit 40 separates and detects the vertical synchronization signal from the broadcast signal of the tuner unit 30 to obtain the microcomputer 20. (Step 202).

Then, the microcomputer 20 counts the number of pulses of the vertical synchronization signal applied using an internal event counter to detect the frequency of the vertical synchronization signal separated from the received broadcast signal (step 204).

Next, it is determined whether the detected frequency is a stable frequency (for example, NTSC 60 Hz, PAL 50 Hz) corresponding to the preset broadcasting method (step 206).

In this case, if the stable frequency, that is, the received broadcast signal is not a weak signal, the microcomputer 20 stores the vertical synchronization data (frequency, A) in the internal memory (step 208).

Next, a count of a predetermined predetermined time is started (step 210), it is determined whether the predetermined predetermined time has elapsed (step 212), and if the predetermined time has elapsed, the broadcast signal received through the tuner unit 30 continues. The vertical sync signal is separated and detected by the microcomputer 20. The microcomputer 20 recounts the number of pulses of the vertical sync signal applied by using an internal event counter, and the frequency of the vertical sync signal separated from the received broadcast signal. Is detected again (step 214).

At this time, it is determined whether the frequency B of the redetected vertical synchronizing signal is out of a predetermined range from the frequency A of the stored stable vertical synchronizing signal (step 216).

At this time, if the frequency B of the redetected vertical synchronization signal is a stable frequency within a range not exceeding a predetermined range compared to the stored frequency A of the stable vertical synchronization signal, the process proceeds to step 210 described above and continues for a predetermined period. The vertical synchronization signal state of the broadcast signal received in units is detected.

On the contrary, if the frequency B of the vertical synchronization signal redetected in step 216 is out of a predetermined range compared to the frequency A of the stored stable vertical synchronization signal, the broadcast signal currently received is a weak signal. The microcomputer 20 generates a pseudo vertical sync signal having a stable frequency stored in the memory of the microcomputer 20 (step 218), and the microcomputer 20 generates an image / image using the stable vertical sync signal generated in this way. The voice signal processing unit 50 is controlled (step 220), and finally, even when the weak signal is used, the stable vertical synchronizing signal is stored in advance, and thus the screen of the monitor 60 due to the instability of the vertical synchronizing signal due to the weak signal reception. This shaking phenomenon can be prevented.

On the other hand, it will be understood by those skilled in the art that various changes and modifications can be made without departing from the spirit of the present invention.

As described above, according to the present invention, the optimum vertical sync signal frequency received from a television is stored regardless of the reception state of the broadcast signal, and if the received broadcast signal is a weak signal, a stable pseudo vertical sync signal having the stored frequency is itself generated. By generating and using, there is an effect that a stable video screen can be displayed at all times regardless of the reception state of a broadcast signal.

Claims (1)

A method for compensating for a weak signal when a vertical synchronization signal received and processed by a television is provided. Separating and detecting the vertical synchronization signal from the received broadcast signal; Counting the frequency of the vertically detected vertical synchronization signal and storing the counted frequency of the vertical synchronization signal when the frequency of the vertical synchronization signal matches the frequency of the preset broadcasting scheme; By counting the frequency of the vertical synchronization signal to be detected and applied separately in a predetermined period unit, if the counted frequency is out of the predetermined frequency and the error range, a pseudo vertical synchronization signal having a frequency of the stored vertical synchronization signal is generated to generate a signal. Using a vertical synchronization signal compensation method in a television.