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Automatic gain controller of digital TV-set receiver

A technology for automatic gain control and television receivers, which is applied in the parts of color TVs, parts of TV systems, TVs, etc., and can solve the problems of reducing SNR, sensitive to the influence of adjacent channels, and signal distortion.

Inactive Publication Date: 2004-07-07
LEIJIN ELECTRONIC SHENYANG CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, if there is an adjacent channel that affects the receiving channel, it will become sensitive to the influence of the adjacent channel due to the gain value that will be obtained in the front section of the SAW filter (102); in addition, multiple RF channels are input to the tuner ( 101), since saturation occurs in the amplifier stage of the tuner, which can distort the signal and reduce the SNR
[0020] Conversely, when the proportion of the IF gain in the rear stage of the SAW filter (102) becomes larger, although the influence on adjacent channels and the saturation state of the RF amplification stage can be prevented, the SNR will be reduced due to further amplification of noise

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  • Automatic gain controller of digital TV-set receiver
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  • Automatic gain controller of digital TV-set receiver

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Embodiment Construction

[0048] In order to realize the single integration of multiple systems, the present invention directly performs RF AGC and IF AGC from the receiving chip; especially, it can calculate the SNR of the received signal, and automatically adjust the reference value of RF AGC according to the SNR value.

[0049] figure 2 It shows the structure block diagram of the digital television receiver of the present invention. The digital integrated chip VSB receiving part (200) used to directly control the RF signal gain and the IF signal gain is composed of the following parts. That is: there is a demodulation part (201) that carries out the VSB demodulation process to the 2nd IF signal that the gain is controlled; There is a SNR calculation part (202) that calculates the SNR value output by the demodulation part;: There is adjustment according to the SNR value RF AGC reference control section (203) of RFAGC reference value; RF and IF AGC section (204) are arranged, and it will utilize RF ...

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Abstract

This invention relates to AGC (automatic gain control) device for digital TV receiver,. Specially can automatically control the reference value of RF AGC (radio frequency automatic gain control) according to the state of channel to ratio of distribute radio frequency and medium frequency, so can make best AGC. Besides, due to digital structure of receiving chip, can carry through RF AGC and IP AGC (intermediate frequency automatic gain control) directly, so it is easy to integrate it into one chip; because it selectively uses receiving signal of pass band and base band to determine gain error, so can improve the function of receiving system.

Description

【Technical field】 [0001] The present invention relates to an automatic gain control device (Auto Gain Control; AGC) of a digital television receiver using a vestigial sideband (VSB) method. 【Background technique】 [0002] figure 1 It is a block diagram of a digital TV structure including a general AGC device. [0003] In the figure, 101: tuner 102: SAW (surface acoustic wave) filter [0004] 103: IF amplification and step-down converter [0005] Digital TV is a TV system developed to allow the intense atmosphere of a theater to be felt at home. Compared with the widely used analog TV, it greatly improves the clarity and width of the picture, and provides CD-level multi-channel audio. [0006] Regarding this type of digital TV, countries such as the United States, Europe, and Japan are developing their own broadcasting standards and specifications to promote their standardization. Taking the United States as an example, the transmission system adopts the vestigial sideba...

Claims

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Application Information

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IPC IPC(8): H04N5/52
Inventor 李泰源
Owner LEIJIN ELECTRONIC SHENYANG CO LTD