C++ Constant-Q

h1. Synthetic test material

h2. Sinusoid at fs/4

In Yeti terms:

<pre>
testStream = manipulate.withDuration 64 (syn.sinusoid 8 2);
cq = cqt { maxFreq = testStream.sampleRate/2, minFreq = 1, binsPerOctave = 4 } testStream;
</pre>

Or to put it another way (in MATLAB this time):

<pre>
test = [0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,-1 ];
out = cqt(test,1,4,4,8)
</pre>

That is, a 64-sample input of 8Hz sample rate containing a sinusoid at fs/4, transformed using CQ parameters fmin = 1, fmax = 4 (or fs/2), and bpo = 4.

h3. Data from MATLAB implementation

<pre>
actual fmin = 1.1892
octaves = 2
weight = 16.3452
drop = 3
kernel size = 32x20
output size = 8x59
</pre>