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i am trying to make a laser microphone as my project.for that i am using pulsed laser.so when the pulsed laser comes to the photodetector after being reflected, there will be a shift in the pulse.so can you please help me to obtain those shifted part[IMG]http://www.engineersedge.com/engineering-forum/attachment.php?attachmentid=1582&stc=1[/IMG]
any help in related fields would be also appreciated .
thanks in advance
Seriously?
Are you making a Laser mic or laser rangefinder?
Since your pulses will be coming back phase modulated by time of flight I don't see where you'll be able to extract much audio information.
You will want to use a PLL (phase locked loop) which if I recall will have a reference input and a signal input and will output a linear control voltage representing the phase error that you can amplify for your "audio" signal.
Most people use a continuous laser, then pick up a reflected amplitude modulated signal using a telescope and photo transistor or similar. Then it's a straight audio amplification problem after that.
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