16 Dec
2007
16 Dec
'07
3:04 p.m.
Subject: Re: Homebrew Drum Computer
From: ard at p850ug1.demon.co.uk (Tony Duell)
Date: Sun, 16 Dec 2007 22:20:38 +0000 (GMT)
To: cctalk at classiccmp.org
Is that a luminance deleay line, to compensate for the different
bandwidths of the luminance and chromanance channels? PAL sets have those
as well,
The delay line I was sgggesting for use as a computer memory device is a
glass block wioth untrasonic transducers on it. It's got a delay period
of almost one complete line-time, and is used to store one of the
chromanace signals as part of the PAL decoding process.
I don't know about PAL but one line for NTSC is only 63us and thats
not enough delay.
Computers that used delay lines were in the milliseconds range as they
needed to store a lot of bits/digit/words.
Allison
I
didn't think the NTSC system used a delay line at the receiver, but I
must admit I've never repaired a US TV set.
Yes they did/do but is was not ultrasonic. The common ones were basically
the same as LONG (4.5us?) transmission lines.
-tony