voice record by matlab

% Audio spectrum display. To exit, close the figure.
%
fs = 22050;                                 % sample rate, hertz
N = 1024;                                   % duration, samples
window = blackman(N);                       % weighting
window = window / mean(window);             % normalize it
gca;                                        % open the figure
while get(0,'CurrentFigure')                % while figure still open
  y = wavrecord(N, fs);                     % acquire some signal
  h = fft(y .* window);                     % transform
  plot(fs*(0:N/2)/N, 20*log10(max(2/N*abs(h(1:N/2+1)), 1e-10)));
  ylim([-160 20]); xlabel('Hertz'); ylabel('dB');
  drawnow;                                  % allow figure to update
end