Ultrasound Doppler sinusoidal shift signal analysis by time-frequency distribution with new kernel

A Cohen's class time-frequency (TF) distribution has high resolution in time and frequency simultaneously on a TF plane. It is a powerful tool for nonstationary signal analysis of the type observed commonly in speech and biological signals. A kernel of high resolution was investigated For its applicability to biological signals. To apply the TF analysis with the new kernel to the analysis of a signal from a blood flow, an ultrasound Doppler sinusoidal shift signal was studied. Experimental data were obtained in olive oil by moving a steel ball to and fro by continuously irradiating it with ultrasound. The movement of the steel bail was controlled by various functions. Three kernels were used: (I) a Wigner kernel, (2) a Choi-Williams kernel, and (3) our new kernel. The demodulation accuracy with our new kernel was higher and negative components were smaller than with the Choi-Williams kernel.