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qu_spectrogram_interactive

Spectrogram - Time-Frequency Analysis

catalog/qu_spectrogram_interactive.qu

Results

Spectrogram: 2001 samples, chirp 10-200 Hz, 14 frames x 129 bins

The whole program

Runnable as it stands: qu run catalog/qu_spectrogram_interactive.qu

# Spectrogram - Time-Frequency Analysis

Fs = 1000
t = 0 to 2 step 1/Fs

f0 = 10
f1 = 200
x = chirp(f0, f1, Fs, length(t))

# @slider window_size 32 512 32

window_size = 256
# @slider overlap 8 256 8

overlap = 128

# Keep the result: Interactive Mode plots workspace variables, so the

# spectrogram has to land in one. `s.db` is the frequency-by-time matrix,

# `s.freq` and `s.time` its axes.

s = spectrogram(x, window_size, overlap, Fs)
title('Spectrogram')
xlabel('Time (s)')
ylabel('Frequency (Hz)')

print "Spectrogram: {length(x)} samples, chirp {f0}-{f1} Hz, {len(s.time)} frames x {len(s.freq)} bins"