Re: [stella] Closed Captioning Query

Subject: Re: [stella] Closed Captioning Query
From: Mark De Smet <de-smet@xxxxxxxxxxxxxxx>
Date: Thu, 29 Aug 2002 21:23:33 -0500 (CDT)
> Re-reading the info I have, I just realized that each cycle of the clock
> run-in is, in fact, one bit width.  So I was incorrect in saying that the

I noticed this too, and I'm suspecting that the decoder uses this clock to
determine the sampling rate of the rest of the data.  If this is true, it
doesn't neccesarily need to all be correct, just spaced
evenly.  Alternatively, as Glenn suggests if newer decoders don't really
use the clock, perhaps we should just give it the couple clocks we can
display, then give it the data in the normal timing.

> data bits are modulated.  (And my calculations in 2 are very wrong.) So
> each bit is either the presence or absence of a cycle (with 0deg=0IRE and
> 180deg=50IRE).  Which means the playfield is eligible, depending on how
> much the decoder requires a sine wave.

The sine wave is only recommended for the clock run in, right?  The spec
only really calls for a symetrical waveform with peaks and lows equal to
the 0 and 1 value.  I don't think it would be a problem to give it square
waves instead.


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