Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!jarthur!nntp-server.caltech.edu!josephc
From: josephc@nntp-server.caltech.edu (Joseph I. Chiu)
Newsgroups: sci.electronics
Subject: Oscillators, PLL's, and FM demodulation - How do you do it?
Summary: How do you make a AM/FM receiver that is computer operated?
Keywords: computers radio scanners transmission reception AM FM modulation
Message-ID: <1990Dec27.183452.18676@nntp-server.caltech.edu>
Date: 27 Dec 90 18:34:52 GMT
Organization: California Institute of Technology, Pasadena
Lines: 30

I need all the help I can get, and thanks in advance to everyone for
reading this post...

For my 3rd sophomore project (or possibly my senior project, depending on
when I have sufficient information), I would like to build a computer
controlled radio receiver.  What I would like to build, essentially, is
a scanner-like device that covers the 25 MHz to 1300 MHz spectrum.

(It is not unreasonable, I should think, since many scanners nowadays cover
 the above spectrum)  

Although I understand the theory behind the operation, I do not have any
practical information on how to go about generating the desired frequencies,
how to use PLL's (are they even necessary if given a stable frequency source?),
and -gulp- how to demodulate FM.  (Apparently, there are 'Narrow' and 'Wide'
modes of FM.)

Could someone recommend a good cookbook (if any), magazine articles, or even
offer a hand?  My current goal for the project, basically, is to build a
prioritized, dual tuning scanner that monitors all (interested) channels, 
and will continue to monitor other channels while 'reading' one channel so
that if a channel of a higher priority breaks in, it will go to that one.

Again, thanks in advance.

-- Joseph
. 
-- 
--
josephc@coil.caltech.edu               ...Just another lost soul in the universe