Email filtering output is capable of throwing messages away.
 Class AB and class B dissipate less power for the same output than class A; general distortion can be kept low by negative feedback, and crossover distortion can be reduced by adding a 'bias current' to smoothen the hand-off
 Real-time, automatic tracing of the Doppler flow profile allows beat-to-beat right-sided and left-sided Q measurements, simplifying operation and reducing the time of acquisition compared to conventional echocardiography

