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Design >> Analog Design >> about video decoder clamp &AGC circuits
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Message started by byellow on May 1^st, 2006, 7:49pm

Title: about video decoder clamp &AGC circuits
Post by byellow on May 1^st, 2006, 7:49pm

what is the fuction of clamp &AGC in video decoder circuits
how to design?
thanks

Title: Re: about video decoder clamp &AGC circuits
Post by gitarrelieber on May 2^nd, 2006, 2:20am

The clamp circuit is responsible for adjusting the input voltage dc level. The video input is AC coupled to chip through a capacitor. Normally the clamp circuit is a current DAC, which charges or discharges the coupling capacitor. You probably will need some sophisticated digital system to control the clamp circuit and so is the AGC.

Maybe you can obtain more details on the hardware implementations in the following reference.

http://www.semiconductors.philips.com/acrobat_download/datasheets/SAA6713H_2.pdf

With regards,
Jiawen Hu
Analog Design