[Coco] question to the hardware gurus (Gene?)

[Neil Morrison]

Yes, low pass. It will strip some of the video out, leaving the horizontal 
and vertical sync signals to be cleaned up.

See http://www.national.com/pf/LM/LM1881.html for a PDF of the manual with 
app notes.

Yes, C3 is the main filter cap.

Neil

----- Original Message ----- 
From: "Torsten Dittel" <Torsten at Dittel.info>


> Would someone have a look at
> http://www.homecinemapage.de/sync.htm
> Who can explain the funtion of the 620 ohm resitance R1 and the 560
> picofarad capacitor in the second schematic? FBAS is composite video. It
> looks like a low pass filter to me, could it be a color burst filter
> (don't know the burst's frequency of PAL)? What if a replacement for the
> LM1881 would have an integrated color burst filter, could I connect the
> video signal directly to C1?
> Same question for C3, what's its function concerning the power supply?
> Removing HF noise from the IC's voltage?