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AD9388A inaccurate LCF

Question asked by DavidF on Jan 18, 2011
Latest reply on Feb 1, 2011 by DaveD

Hello there,

 

I'm just measuring the incoming analog RGBHV signal to the AD9388A and reading back the STDI values. It's weird, but LCF seems to unaccurate. E.g. the source is set up to send 901 line per vsync - and I've verified this by an logic analyzer - but the LCF value differs from that - it varies between 898 or 900 after every reinitialization.

 

The hardware manual (revJ) gives also an interval for the LCF to each resolution in the table 48. ,,STDI Readback Values for Graphics Standards". Is this because the LCF is an inaccurate measurement? What are the absolute limits for the error?

 

(just for record: I'm using1152x864p72 resolution with 901 lines and with 1152 total hsize in auto graphics mode. The STDI_DVALID is 1)

 

thank you in advance

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