linuxaudio.org

On 06/25/2011 04:23 PM, pshirkey@boosthardware.com wrote:

quoted text
> Hi,

>

> Can anyone point me to a simple code example for how to determine the

> phase at a specific time in a waveform?

>

> ex. if I have a sample that is 5 seconds long and want to know the phase

> at 2.5 seconds

talking about the "phase" at some particular point in time doesn't make

sense. first you would have to do an fft (whose resolution is bound by

the window size), and then you'd have to look at each frequency bin

separately, because they will all be at different relative phase.
when you talk directly into my ear, the voice/ear system will be roughly

zero phase. when i move away even a few inches, there will be a linear

phase "distortion" due to the fact that i'm now one wavelength away at

some mid frequency, but several wavelengths at high frequencies.
so "phase" is not really a meaningful thing unless you are talking about

recombination of strongly correlated signals.
another example: if your sample consists of a sine at 100hz and one at

200hz, after 10ms the first component will be at 0° while the second is

at 180°, iff both started at 0° in the first place. but why would anyone

care? with real-life sounds, this whole exercise becomes meaningless.
what are you trying to accomplish?
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