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From: firstname.lastname@example.org (Frank Miles)
Subject: Re: Sending an analog signal using RF components
Date: 28 Oct 2002 18:14:55 GMT
Organization: University of Washington, Seattle
References: <email@example.com> <firstname.lastname@example.org>
In article <email@example.com>,
>firstname.lastname@example.org (Frank Miles) wrote in message news:...
>> Bandwidth (of original signal) ?
>It's a DC signal.This signal CAN change 50 times per seconde.But it's
>still a DC signal.
>> How electrically noisy is the environment?
>Well, It's outdoor, by the side of a road.And probably close to
>> Is location of signal moving?
>No.The transmitter and the receiver are immobile.
>> Power constraints?
>5V on the transmitter side and 120 VAC(no limit) on the receiver side.
>Hope this is better,
Well, you still haven't said much about accuracy. Assuming you don't
need a whole lot, the 555 timer idea (mentioned by someone else) is
pretty reasonable for a low-bandwidth situation (if the "dc" voltage
is changing, it's _NOT_ dc!).
You can feed the input voltage into the 'control voltage' pin of the 555
timer. The output is sorta linear if you look at it as a proportional signal,
though the total time/period will vary -- just feed into a lowpass filter
at the FM receiver output. Use the 555 output to modulate a 1-transistor
oscillator/RF output stage via a varactor diode. Or one of the other ideas
that's been suggested...
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