Instantaneous frequency tracking of a sine wave phase modulation signal

When a signal is modulated by a sine with a low index of modulation, the tracking of the instantaneous frequency encounters many difficulties. In the application of acoustic velocity measurement by means of laser Doppler anemometry, the limitations appear quite rapidly with the signal processing now available. The approaches, proposed assume a knowledge of the modulation frequency and need several modulation periods inside the analysis window. The time-frequency detector developed, called global demodulation transformation, is based on a kernel adapted to the signal to be analysed. Simulations prove the interest of these approaches