Вот пример для различных последовательных частот.
% Generate a sequencial sinusoid
fs = 8000; % sampling rate
amp = 1; % amplitude
freqs = [262, 294, 330, 350, 392, 440, 494, 523]; % frequency in Hz
T = 1/fs; % sampling period
dur = 0.5; % duration in seconds
phi = 0; % phase in radian
y = [];
for k = 1:size(freqs,2)
x = amp*sin(2*pi*freqs(k)*[0:T:dur-T]+phi);
y = horzcat(y,x);
end