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Old 28th Feb 2005, 6:19 pm   #26
David_Robinson's Avatar
Join Date: Feb 2004
Location: Nottingham, UK
Posts: 94
Default Re: Multi-Channel VHF Modulator Design

Originally Posted by oldeurope
... programm the PIC. I am not able to do this.
If you want to build this design I can send you the programming file. You just need a PIC programmer (mine cost about 50).
The leak current of this cap can change the bias!
The cap I used is a ceramic chip (surface mount) not an electrolytic. The leakage is very low.
... place the electrolytic from the bias pot to ground to block noise from the 5V.
Good point although I haven't noticed a problem.
Originally Posted by flyback
... your video should be band limited to ~3.0MHz, is this somthing that you have found is a problem?
Well, keep this to yourself as it is very hush-hush, but I am developing a standards converter too, and this produces the input video bandwidth times 405/625 which is a bit more than 3MHz...
Look that up in your Funk and Wagnall's

Last edited by Dave Moll; 27th Jun 2007 at 10:23 pm. Reason: correct for username change in quote
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