[78-L] Removing hiss - yet another idea

[Christopher Steward]

The Packburn switches between the mono signal or either of the two channels, depending on which is the quietest. Although it works quite well, it seems to me that the inherent flaw in that system is that a distortion of the signal can result in a quieter signal - a small tick can be a bite out of a positive part of a waveform - in which case the switcher will choose the wrong channel. Any digital program copying the Packburn will have the same problem.
Chris

--- On Tue, 9/2/10, Michael Biel <mbiel at mbiel.com> wrote:


From: Michael Biel <mbiel at mbiel.com>
Subject: Re: [78-L] Removing hiss - yet another idea
To: "78-L Mail List" <78-l at klickitat.78online.com>
Date: Tuesday, 9 February, 2010, 5:07


This was done over 35 years ago by Richard Burns and David (?) Packard 
in a device called the Packburn.  It had a switching circuit which 
selected the quieter of each groove wall, and then was improved to use 
the combined pair when both are equal.  You could watch the lights 
following the action.  Following the switcher it had a blanker which was 
an impulse de-clicker which removed the click and interpolated the 
missing sound with what preceded and followed it. 

And this was long before our mutual friend Lloyd Stickles developed the 
original idea that became CEDAR.  I was at early presentations of all of 
these devices.

Mike Biel  mbiel at mbiel.com