Method and device for suppressing second harmonic used in digital TV set-top box

Abstract

The invention discloses a method for suppressing the second harmonic used in a digital TV set-top box, which comprises the following steps: according to the frequency domain information of the frequency point whose frequency is one-half of each preset frequency point, the frequency is calculated as the frequency of each preset frequency point The second harmonic information of the frequency point that is half of the frequency point; receive the locked frequency point, the locked frequency point is included in the preset frequency point; from the frequency domain information corresponding to the locked frequency point The second harmonic information of the frequency point whose frequency is half of the locked frequency point is subtracted to obtain the filtered frequency domain information of the locked frequency point. By adopting the technical scheme of the invention, the second harmonic can be effectively suppressed.

Description

technical field [0001] The invention relates to the field of suppressing second harmonics, in particular to a method and device for suppressing second harmonics used in a digital TV set-top box. Background technique [0002] In the digital TV broadcasting system, when the digital TV set-top box receives cable, satellite or terrestrial signals, the signal transmitted by the front end is relatively weak when it reaches the digital TV set-top box after transmission, and usually uses some special circuits to process the incoming signal from the front end For example, use an operational amplifier to amplify and then send it to the back-end for processing. These special circuits not only amplify useful signals, but also amplify useless signals such as second harmonics during processing, which leads to the inability to effectively distinguish which are useful signals and which are useless signals during back-end processing. As a result, the performance parameters of the machine ar...

AI Technical Summary

Problems solved by technology

These special circuits not only amplify useful signals, but also amplify useless signals such as second harmonics during processing, which leads to the inability to effectively distinguish which are useful signals and which are useless signals during back-end processing. The performance parameters of the machine are greatly reduced

[0003] In order to suppress the second harmonic, the existing technology mainly uses some compensation circuits to suppress the second harmonic when processing the front-end signal. This method not only increases the cost, but also introduces Due to some uncertain factors, the front-end processing circuit cannot achieve the expected effect

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