An approach for adaptively adjusting the correlation window for open-loop
pitch determination is presented. Correlation between a windowed
reference signal (or target signal) and a candidate signal is maximized
under most conditions by sliding the reference window by a delta
increment in either direction to capture peak energy. The traditional
fixed size of the correlation window is maintained. However, the window
slides forward and/or backwards to capture peak energy within the window.
The position of the adjusting or sliding window is allowed to shift in a
small range or increment in either direction to maximize the energy of
the windowed signal thus making sure that at least one peak energy is
captured within the window.