Method for determining whether there is digital signal in digital TV set

Abstract

The method carries out following flow: if signal received from each channel, the method determines PWL (Power Level) of kernel point setup in advance at specific location of the said each received signal, and determines whether the PWL value is within critical range; if yes, then determining whether deviation of PWL value is within critical range setup in advance; if yes, then the said input signal is determined as digital signal. The method ensures that decoding function is operated only for meaningful digital signal so as to guarantee stability and service time of chip.

Description

technical field [0001] The invention relates to a method for judging the presence or absence of a digital signal by a digital television. When the digital television automatically searches for a channel, a VSB (Vestigial Sideband Amplitude Modulation) / QAM (Quadrature Amplitude Modulation) decoder judges whether the digital signal exists or not. Background technique [0002] With the development of the digital age, in the field of television broadcasting, work related to digital broadcasting standards is also in full swing. When purchasing a digital TV, when it is installed for the first time or every time it is moved, in order to grasp the status of the network, the digital TV activates the internal memory storage function of the information about the effective channels that can be received. This is called ACS (Auto-channel scan) . The searched channel information is stored in the internal memory of the digital TV, and the channel-related start-up action of the digital TV i...

AI Technical Summary

Problems solved by technology

[0008] However, there is such a problem in the above-mentioned current technology that it can only judge whether the signal input from the terminal exists or not, and cannot sense the digital VSB / QAM signal, so it cannot be used effectively

[0009] In addition, take the VSB / QAM decoder as an example. Although it has a chip for processing digital signals, when the digital TV runs the automatic channel search function, it first sets the VSB or QAM for all signals, and then performs decoding to determine whether the channel exists or not. Therefore, there is a problem that it takes a long time

[0010] In addition, using the BLOCK (function block) that only judges the existence of the input signal in the previous chip function saves time during the automatic channel search process, but when the analog signal or noise that is not a digital signal exists in the tuning channel, it is also It is judged that the signal exists, and the decoding time is wasted for unnecessary channels

[0011] In addition, analog signals that are not digital signals, meaningless signals, or even signals that do not exist, also go through the decoding process of the decoder. Therefore, it takes time to judge whether there is a normal signal in the relevant channel, and it also affects Decoder chip usage time and its performance

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