# Hi,
# I want to multiply the spectrum of a signal with an arbitrary
function. As I searched through the manual this can be done using
pvsanal, pvsmaska, a function table and, pvsynth. I made something
which works but to exactly understand what I made I would like to get
some more information.
# In manual, for pvsanal, it says that:

For example, where ifftsize = 1024, fsig will contain 513 analysis
bins, ordered linearly from the fundamental to Nyquist.

# Why there are 513 bins, not 512? Is bin number 0 for DC component or
fundamental component? Is Nth_Bin for the frequency
(SampleRate/1024)*(N-1)?
# So should my function table, which will contain the transfer
function of the filter, has 512 or 513 points?

# In manual it says also:

Currently only one format is implemented by this opcode: 0 = amplitude
+ frequency

# What does this exactly mean? I understand something like this:
# fsig is an array. Its elements are pair of numbers, one for
amplitude and one for frequency. Because pvsanal does not take FFT but
makes a phase-vocoder analysis, frequency values are not exactly
integer multiples of some fundamental, SR/1024, but they deviate from
their corresponding bin value. How are these deviations stored? Are
the freq. values absolute freqencies in Hz, or are they deviations
(delta f) from the frequencies corresponding each bin, or something
like these?
# This info will be useful if I try to use pvsftr.
-ugur guney-