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From: "Mr Kian Loh"
Subject: Re: concept behind FM transmitter bug
Date: 7 Sep 2002 09:15:51 GMT
Organization: The University of Queensland (my.UQ Portal)
NNTP-Posting-Date: 7 Sep 2002 09:15:51 GMT
i currently building a transmitter circuit based on design i got from the web
but it did not work.
It is a 2 stage BJT transistor FM transmitter. The first stage is the preamp for
the electret mic. The second stage is a colpitt oscillator.
I am wondering anyone could tell me if the output stage of such common
transistor is an oscillator configuration. I did not see any waveform on the
60Mhz oscillope. Though the transmitter work in the range of 88-103 Mhz. I will
still get to see something rite?
What is the different between electret mic and condenser mic?
I try building each stage separately to test if the amp and oscillator works
independently. It seems that oscillator config does not give me any result. When
i remove the variable cap, it show me 50 Mhz sine wave. This i believe is
correct as the LC config left on the breadboard give me 50Mhz.
Is that a way to view a waveform of 90Mhz on a 60Mhz oscilloscope?
Many thanks in advance.
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