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## How can I increase/decrease (frequency/pitch) and phase using fft/ifft t

 From: Rick T Subject: How can I increase/decrease (frequency/pitch) and phase using fft/ifft tia sal22 Date: Mon, 4 Apr 2011 11:11:04 -1000

How can I increase/decrease (frequency/pitch) and phase using fft/ifft
I think I have the basic code but I’m not sure what to do next

PS: Thanks for the help on the last question everyone I decided not to use the FOR loop and sin/cos values and just use fft/ifft
to see if this will work.

Example I have a signal that repeats 1 time every second and I want to
have it repeat 3 times a second instead.

%Voiceprint raise lower freq phase conjugate signal
tic
clear all, clc,clf,tic
%% Sound /beep calculation complete
filerawbeepStr='calculations_complete.wav';
filerawbeeppathStr='/home/rat/Documents/octave/raw/';
filevoiceprepathStr='/home/rat/Documents/octave/eq_research/main/
transform/voice/';
filewavpathStr='/home/rat/Documents/octave/eq_research/main/transform/
wav/';
[ybeep, Fsbeep, nbitsbeep] =
%add path to location of functions

%1a voice print import
[vp_sig_orig, fs_rate, nbitsraw] =

%vp_sig_orig=vp_sig_orig’;
vp_sig_len=length(vp_sig_orig);

%2a create frequency domain
ya_fft = fft(vp_sig_orig);
vp_sig_phase_orig = unwrap(angle(ya_fft));

%get Magnitude
ya_fft_mag = abs(ya_fft);

%3a frequency back to time domain
ya_ifft=real(ifft(ya_fft));