[Coco] [coco3] upscan video converter

[jdaggett at gate.net]

On 16 Jul 2005 at 13:45, RJRTTY at aol.com wrote:

From:           	RJRTTY at aol.com
Date sent:      	Sat, 16 Jul 2005 13:45:51 EDT
Subject:        	Re: [Coco] [coco3]  upscan video converter
To:             	coco at maltedmedia.com
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>    I displayed it at the last cocofest in chicago.   On that monitor
>    there
> were no artifacts.   The design schematic I based it on did use
> a bunch of ferrite beads to seperate different supplies.    It even
> seperated multiple analog supplies from each other even with the same
> voltage. 

A bit of an overkill but if money is no problem then it is okay. Biggest concerns 
when laying out power and ground that power runs are such that they do not form 
any kind of loops. Even then well placed and correct value of caps will kill resonace 
of a loop. 


>What i did was use only one filter to seperate analogue from
> digital supplies on the same regulator. This used only two ferrite
> beads as opposed to 10 or 12.     But the image didn't suffer.   The
> image looks like it was painted on.  It was very high quality.    That
> was one of the reasons I committed to the project.     I wouldn't
> waste my time otherwise. :)

Beads are nice if you are intending to supress a band of frequencies. Beads tend to 
for a bandpass filter. A simple PI network with resistors or inductors and capacitors 
will form nice low pass filters on power lines. 

james