Re: [stella] I really need to buy a scope

Subject: Re: [stella] I really need to buy a scope
From: Chris Wilkson <ecwilkso@xxxxxxx>
Date: Wed, 11 May 2005 18:40:16 -0400's a DC voltage!

Where by "DC" I mean it's a voltage divided form of VCC, unbuffered
of course.  This voltage is what controls the stage delay in the
color delay chain.  Due to capacitive coupling, the color pulse
that propagates through the chain at 3.579545 MHz will show up on
this line.  And because it passes though 15 stages of delay (15 or
so...I don't have my schematic in front of me) the pulse gets coupled
15 (or so) times per cycle -> 53.693175 MHz.

Hmm...looks like you have 14 stages of delay in your system.

Despite all of this, the delay (pin 10) input is supposed to be a DC
voltage.  If you actually measure it, it will look like a DC voltage
with some high frequency (~50 MHz per above) noise riding on it.
Plus any noise that comes from VCC.


On Wed, 11 May 2005, Adam Wozniak wrote:

> Hash: SHA1
> Does the delay signal on the TIA (pin 10) have a frequency of about
> 50.113630 MHz?
> I really need a scope.  *sigh*
> - --
> adam@xxxxxxxxxxxxxxxx
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