FM Doppler ultrasound system

This paper describes an ultrasound Doppler system utilizing swept frequency (FM) excitation. Both range and velocity data can be obtained from the received signals by means of either of two different signal processing approaches: Frequency (or spectral) Shift Measure­ments (FM-fsm) or Phase Shift Measurements (FM-psm). The unique features of the FM Doppler system are the low peak power, possibility for pre-compensation of attenuation and transducer effects, and — for the FM-fsm processing technique — the absence of aliasing effects.