Test Program for F0 Estimation

The following test program generates a harmonic signal and uses f0est to determine the fundamental frequency, first with all harmonics present, and second with the fundamental suppressed by a notch filter.

% Tested using Octave 3.0.0, Aug 2008

clear all;

f0 = 440;    % true fundamental frequency
n = 1:200;   % time in samples
fs = 10000;  % sampling rate

N = length(n);
fund = sin(2*pi*f0*n/fs); % sine at fundamental frequency
npartials = 7;
sig = zeros(1,N);
for k=1:npartials
  ampk = 1 / k^2; % give a natural roll-off
  sig = sig + ampk * sin(2*pi*k*f0*n/fs);
end
%rmsnoise = 0.01;
rmsnoise = 0.0;
sig = sig + rmsnoise * randn(1,N); % add some noise for realism

framesize = N;
minlevel = -60; % Lowest relative partial amplitude to accept
                % (-40 good with Hamming window family)
                % (-60 good with Blackman window family)
debug = 0;
f0 = f0est(sig,fs,framesize,npartials,minlevel,debug)
% Trick to leave all internal f0est variables defined
% (comment-out first line of f0est.m declaring the function):
% nargin = 6; f0est;

% Notch out fundamental and repeat:
b1 = -2*cos(2*pi*f0/fs);
sig = filter([1 b1 1],1,sig);
f0 = f0est(sig,fs,framesize,npartials,minlevel,debug)

% Example output:
% f0 =  439.99
% f0 =  437.50

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About the Author: Julius Orion Smith III
Julius Smith's background is in electrical engineering (BS Rice 1975, PhD Stanford 1983). He is presently Professor of Music and Associate Professor (by courtesy) of Electrical Engineering at Stanford's Center for Computer Research in Music and Acoustics (CCRMA), teaching courses and pursuing research related to signal processing applied to music and audio systems. See http://ccrma.stanford.edu/~jos/ for details.