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- Newsgroups: sci.electronics
- Path: sparky!uunet!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!athena.cs.uga.edu!aisun3.ai.uga.edu!mcovingt
- From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
- Subject: Re: Crystal-controlled FM XMTR?
- Message-ID: <1992Nov9.033136.28608@athena.cs.uga.edu>
- Sender: news@athena.cs.uga.edu
- Organization: AI Programs, University of Georgia, Athens
- References: <1992Nov5.162651.7465@unislc.uucp> <1992Nov6.200359.27073@ms.uky.edu> <1992Nov6.204019.6938@news.nd.edu>
- Date: Mon, 9 Nov 1992 03:31:36 GMT
- Lines: 21
-
- In article <1992Nov6.204019.6938@news.nd.edu> fdeck@dumpster.helios.nd.edu (francis deck) writes:
- >I've seen talk about one-chip FM transmitter circuits, but it
- >appears they are all slug-tuned and experience frequency drift.
- >Is there a simple circuit out there which is a monaural or
- >stereo (doesn't matter for my application) FM transmitter,
- >but which has a crystal timebase? I'd imagine it'd use some
- >sort of PLL, but at 89 to 108 MHz, I'm lost. Any help?
-
- Hmmm, there isn't, but there should be. It's easy to "pull" a crystal
- by using a (modulated) variable capacitance across it. To get enough
- deviation to be audible on an ordinary FM radio, you'd probably want to
- use a crystal at perhaps 1/27 the eventual frequency, and then triple
- it several times (thereby also tripling the deviation).
-
- See the Radio Socy. of Great Britain VHF/UHF HANDBOOK.
-
- --
- :- Michael A. Covington internet mcovingt@uga.cc.uga.edu
- :- Artificial Intelligence Programs phone 706 542-0358
- :- The University of Georgia fax 706 542-0349
- :- Athens, Georgia 30602-7415 U.S.A. amateur radio N4TMI
-