Digital IF demodulator

A technology of intermediate frequency demodulator and digital intermediate frequency signal, which is applied in the direction of TV, color TV parts, electrical components, etc., and can solve the problems of anti-interference and high frequency deviation

Inactive Publication Date: 2011-11-30
HIMAX MEDIA SOLUTIONS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Based on the above considerations, a digital IF demodulator that demodulates IF analog TV signals in an all-digital manner is needed to solve the problems of anti-interference and high frequency deviation in carrier restoration

Method used

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Embodiment Construction

[0033] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the preferred embodiments are specifically cited below, and in conjunction with the accompanying drawings, the detailed description is as follows:

[0034] figure 1 A block diagram of a digital IF demodulator 100 for an analog television system according to an embodiment of the invention is shown. The analog TV system includes a frequency adjuster 110 , a filter / ADC circuit 115 , a digital IF demodulator 100 and a video signal synchronizer 190 . The digital intermediate frequency demodulator 100 includes a down conversion circuit (down conversion circuit) 140, a sampler (decimator) 150, a numerically controlled oscillator (Numerically Controlled Oscillator, NCO) 160, a picture intermediate frequency (picture intermediate frequency, PIF) carrier restoration circuit 170 and a baseband video demodulator (video baseband modulator) 180. The filte...

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Abstract

The invention discloses a digital intermediate frequency demodulator for processing digital intermediate frequency signals converted from radio frequency signals, including a numerical control oscillator, a frequency down conversion circuit, an image intermediate frequency carrier restoration circuit and a baseband video demodulator. A numerically controlled oscillator is used to output sine and cosine values. The frequency down conversion circuit outputs a first zero intermediate frequency signal including a first real part signal and a first imaginary part signal according to the digital intermediate frequency signal, the sine value and the cosine value. The image intermediate frequency carrier restoration circuit outputs the loop error signal to the numerical control oscillator and the second zero intermediate frequency signal according to the first zero intermediate frequency signal and the video synchronization signal. The baseband video demodulator generates a composite video signal according to the second zero-IF signal.

Description

technical field [0001] The invention relates to a digital intermediate frequency demodulator (Intermediate Frequency demodulator, IFdemodulator), in particular to a digital intermediate frequency demodulator for enhancing the synchronous capability of a television system. Background technique [0002] Traditional analog TV broadcasting systems, such as National Television System Committee (NTSC), Phase Alternating Line (PAL) and Séquential Couleur Avec Mémoir (SECAM) systems, baseband video of program content And audio signals are modulated to a specific intermediate frequency according to the modulation technology specified by individual TV systems, and then the intermediate frequency is filtered, up-converted, and power amplified to form a modulated signal with a specific radio frequency (Radio Frequency, RF) frequency. Finally, the RF signal is transmitted through the antenna into the air or into the coaxial cable. Taking the NTSC system as an example, the baseband video...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04N5/455
Inventor 蔡典儒施姵君
Owner HIMAX MEDIA SOLUTIONS
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