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ADV7188 - ADV212 Problems - Urgent !

Question asked by antenci on Mar 13, 2014
Latest reply on Dec 26, 2014 by antenci

Hello,

We want to decode PAL video signals to JPEG2000 codestream data through ADV7188 and then ADV212. We have managed to get the jpeg2000 video stream but still have some problems.

1- deinterlaced video has a vertical vibration.

2- in addition to the vertical vibration, there are problems with the first and last lines of the frame. While vibrating, these lines show only half of the line.

First line has about 280 black pixels from the left and picture untill the line end and at the same time last line has picture pixels from beginning of the line to the same coordinate (280) and black pixels after that point. And next, it becames reverse.

By the time we use eav-sav mode.

3- picture sometimes gets darker, and sometims it is bright. There is a dc level problem i think.

4- ADV7188 requests 0.5V-1.6V and 1Vpp video signal to correctly digitize.My ac coupled (via 100nF cap) video signal is 1Vpp but dc level iss different. when i dont connect the camera cable, there is about 1.7V dc level for clamping video. After the connection, signal is still 1Vpp but dc levels are between about 1.3V to about 2.3 V. Exceeds 1.6V. if i disable the clamp current sources, i see ac coupled 1Vpp video after the capb but dc level is below 0V.

Are these normal levels?

By the way: citcuit connection is 19 ohm 56ohm voltage divider and then 100 nF cap.

Need your advises.

Thanks.

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