Instantaneous Frequency

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Jetson Ronald
Jetson Ronald il 4 Ago 2011
Hello
I am estimating the Instantaneous Frequency of my signal using the following code.
h=hilbert(acc);
unrolled_phase = unwrap(angle(h));
inst_freq = ((diff(unrolled_phase))'./diff(T))/(2*pi);
I get both positive and negative frequencies (very few) also some spikes. How to avoid negative frequency and unrealistic. frequencies?

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Daniel Shub
Daniel Shub il 5 Ago 2011
Your problems are coming from the unwrapping of the phase. Your estimate of the instantaneous frequency can only be negative if diff(unrolled_phase) is negative. Just add 2pi to those points (and all the values after).

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