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From: ken@cs.rochester.edu (Ken Yap)
Newsgroups: sci.electronics
Subject: Re: FM audio recording?
Message-ID: <2459@sol.ARPA>
Date: Mon, 21-Sep-87 01:20:22 EDT
Article-I.D.: sol.2459
Posted: Mon Sep 21 01:20:22 1987
Date-Received: Tue, 22-Sep-87 01:07:57 EDT
References: <3746d52b.b8ab@apollo.uucp> <231@piglet.UUCP> <1574@dicome.UUCP> <235@piglet.UUCP>
Reply-To: ken@cs.rochester.edu (Ken Yap)
Organization: U of Rochester, CS Dept, Rochester, NY
Lines: 14

|I cannot find my reference just now, and perhaps the radio buffs out
|there can clarify.  Although FM broadcast channels are spaced 200KHz
|apart(which is obvious just looking at the dial)  there exist in that
|channel guard bands, pilot signals, and subbands.  I believe(and if anyone
|out there knows differently they are welcome to correct me) that the
|actual audio portion of the main FM band takes up around 160 KHz.

Actually, if I remember all those Bessel functions they taught us, FM
results in infinite sidebands but attenuates rapidly away from the
carrier so for practical purposes the bandwidth is decreed to be the
width at which the sideband drops to X dB below the carrier, where
X is something like 75.

	Ken