COMPARISON OF DOPPLER SIGNAL ANALYSIS TECHNIQUES FOR VELOCITY WAVE-FORM, TURBULENCE AND VORTEX MEASUREMENT - A SIMULATION STUDY

Simulated time-varying Doppler signals incorporating bandwidth, power variation and vortex simulation have been used to compare a number of signal analysis techniques with a view to optimising the accuracy of c onvective velocity waveform, spectral broadening and vortex signal est imation. The short-time Fourier transform (STFT), the autoregressive ( AR) modified covariance estimator, the time-frequency pseudo-Wigner-Vi lle and Choi-Williams distributions and a partial stationarising algor ithm were investigated for a range of some analysis parameters (such a s window duration, AR model order). It was found that all methods coul d estimate the convective velocity waveform well and all the nonclassi cal methods were an improvement over the STFT for bandwidth estimation with the stationarising method giving the lowest error. For vortex me asurement, using parameters that were optimum for mean frequency and b andwidth estimation, the stationarising, modified covariance, pseudo-W igner-Ville with a IO-ms window and Choi-Williams methods gave improve d performances compared with the STFT.