# Stereo signal phase shift

by keithmarsh
Tags: phase, shift, signal, stereo
 P: 2,251 to relate time difference (ITD) to azimuth direction, you need to review the Blumlien stereo patents. (or just do a little trigonometry. assume no head shadowing, but that you know the inter-aural spacing.) to get the ITD you want to compute the "cross-correlation" between the signals of the two microphones: $$R_{lr}(\tau) = \int (x_l(t) x_r(t-\tau)) w(t) dt$$ where $w(t){/itex] is a window function. if you're doing this with a DSP (or some other real-time processor), then the above integral is a summation and the signals are discrete-time. and the offset lag [itex]\tau$ is also an integer number of samples. if you like USENET, comp.dsp is a good newsgroup for this question.
 Quote by rbj to relate time difference (ITD) to azimuth direction, you need to review the Blumlien stereo patents. (or just do a little trigonometry. assume no head shadowing, but that you know the inter-aural spacing.) to get the ITD you want to compute the "cross-correlation" between the signals of the two microphones: $$R_{lr}(\tau) = \int (x_l(t) x_r(t-\tau)) w(t) dt$$ where $w(t)$ is a window function. if you're doing this with a DSP (or some other real-time processor), then the above integral is a summation and the signals are discrete-time. and the offset lag $\tau$ is also an integer number of samples. if you like USENET, comp.dsp is a good newsgroup for this question.