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From: brianw@microsoft.UUCP (Brian Willoughby)
Newsgroups: comp.sys.apple
Subject: Re: GS quadrophonic sound
Message-ID: <9033@microsoft.UUCP>
Date: 15 Nov 89 03:08:26 GMT
References: <1036@mountn.dec.com> <36310@apple.Apple.COM> <1989Nov10.175249.9131@alberta.uucp>
Reply-To: brianw@microsoft.UUCP (Brian Willoughby)
Organization: Microsoft Corp., Redmond WA
Lines: 29

In article <1989Nov10.175249.9131@alberta.uucp> c326-18@jasper.UUCP (Keen Jeffrey) writes:
>  We all know that is S in GS stands for sound.  Stereo cards abound but
>the GS is capable of much more.  The following circuit uses the same 
>technique as stereo cards to decode stereo but decodes quadrophonic.
>
>IC2   			: 74F139N  dual 2 to 4 decoder 
>IC5 - IC6		: 4016  cmos SPST analog switch
>IC7			: 4069  cmos hex inverter

Keen,

While there is nothing *wrong* with your circuit, I thought that I would
mention that the functionality of IC2, IC5, 6 & IC7 are combined in a few
standard CMOS chips.  It turns out that your circuit is so useful in many
applications that you can easily find it in one chip, thus saving wiring
and lowering noise.

Look for a Siliconix DG506 or any make of 4058.  I'm not absolutely sure
about the number 4058, but just check in any CMOS 4000 series list for
an 8-channel to 1 analog multiplexer/demultiplexer (not the digital type,
they won't handle audio/sound signals).

Happy circuit hacking...

Brian Willoughby
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