  A new time-delay estimation (TDE) technique based on dynamic programming is
developed, to measures the time-varying time-delay between two signals. Dynamic
programming based TDE technique provides a frequency response 5 to 10 times
higher than previously known TDE techniques, namely those based on time-lag
cross-correlation or wavelet analysis. Effects of frequency spectrum,
signal-to-noise ratio and amplitude of time-delay on response (represented as
transfer function) of TDE technique is studied using simulated data signals.
Transfer function for the technique decreases with increase in noise in signal;
however it is independent of signal spectrum shape. Dynamic programming based
TDE technique is applied to the Beam-Emission-Spectroscopy (BES) diagnostic
data to measure poloidal velocity fluctuations, which led to the observation of
theoretically predicted zonal flows in high-temperature tokamak plasmas.
