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Posting-Version: version B 2.10.2 9/5/84; site angband.UUCP
Path: utzoo!linus!philabs!cmcl2!seismo!ut-sally!mordor!angband!sjc
From: sjc@angband.UUCP (Steve Correll)
Newsgroups: net.audio
Subject: Re: FM compression
Message-ID: <23@angband.UUCP>
Date: Fri, 5-Oct-84 13:16:08 EDT
Article-I.D.: angband.23
Posted: Fri Oct  5 13:16:08 1984
Date-Received: Sun, 7-Oct-84 04:44:43 EDT
Distribution: net
Organization: S-1 Project, LLNL
Lines: 23

>  As one who listens to FM both at home on a quality (my opinion :-) system,
>  where I want wide dynamic range in the source material, and on a cheapy
>  headphone radio, where I want consistently high-level audio to drown out
>  the noise of the bus...I would think the answer would lie in putting the
>  compression in the RECEIVER, not in the transmitter.

Unfortunately, when the compressor in the receiver boosts quiet
passages, it will also boost noise and interference acquired during
transmission.  Instead, why not use a well-defined compression scheme
at the transmitter? Then if you want wide dynamic range, you undo the
compression at the receiver with complementary expansion; otherwise,
you leave the signal compressed to drown out the noise in your
listening environment.

Stations which Dolby-encode their signal would produce roughly the
desired effect, except that (a) Dolby compression is rather mild, and
(b) Dolby compression is frequency-dependent, so therefore the stations
mess around with the equalization in the transmitter.  The unpopularity
of the Dolby system among broadcasters suggests that they don't care
much about our problems anyway.
-- 
                                                           --Steve Correll
sjc@s1-c.ARPA, ...!decvax!decwrl!mordor!sjc, or ...!ucbvax!dual!mordor!sjc