View Full Version : Phase of in incoming signal

03-26-2009, 08:35 PM
I was looking at SN96's post under completed projects about "My Stamp Audio Sensor" and wanted to take this a little further.

I was wondering if the propeller can determine the phase difference of a signal coming in from different pins. For instance if I was feeding in two different signals (both sine waves) into two different pins and the phase was different by say 80 millisecs. Is there a way to calculate that?

I want to experiment with detecting sounds and determining the timing difference between two microphones in order determine direction.

Thanks for any help you may offer.


Post Edited (Eric) : 3/26/2009 2:59:57 PM GMT

Phil Pilgrim (PhiPi)
03-26-2009, 10:42 PM
Are you sure you meant 80ms as an example? That would entail a sine wave of less than 12.5Hz. Otherwise, it would not be possible to to detect a phase difference greater than one cycle, unless the incoming waves were more complex with distinguisable features at that scale.


03-26-2009, 11:16 PM
I'm sorry... 896 microseconds... If my math is right... If I initiate a sound and I have two microphones spaces 12" apart the maximum delay between them to hear the sound is 896 microsecs ( if my calculations are right at Sea level). Which would indicate that the sound is coming at a right angle to the microphones.. and the delay would be very minimal if at anything if the sound was ahead at 0 degrees.