Re: laser FM detector

On Sat, 23 Feb 2008 06:18:53 -0800 (PST), j2.macalinao@xxxxxxxxx
wrote:

Greetings! I'm a fresh college student currently learning electronic
communications. I have been planning on a project that makes use of
lasers to transmit signals through the laser beam, shifting a beam
using a mirror mounted on a vibrating speaker cone.

For the receiving end, I'll be making a simple slope detector + audio
amp circuit that would hopefully demodulate the signal. But instead of
an antenna (which is particularly useless in my project), I will be
using a simple photodiode that would change the frequency of a signal
(from an AC source, most likely a signal gen) according to the angle
shifting of the beam, even though there's a little difference.

How can a photodiode change the frequency of a signal from a signal
generator?

John


.

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