FIELD: physics.
SUBSTANCE: imaging system comprises an ultrasound probe, operating at an ultrasonic Doppler transmission frequency f0, a Doppler demodulator which produces Doppler shift signals from the velocity of blood flow in an audio frequency band, a Doppler information display, an audio Doppler system, responsive to the Doppler shift signals, which produces a pitch-shifted Doppler audio signal without changing the displayed blood flow velocity. A Doppler audio system is responsive to a user control device in order to shift the pitch of Doppler-shifted signals by a fraction or whole number of cycles in order to maintain the tone quality of Doppler audio signals.
EFFECT: use of the invention expands the frequency range within an audio frequency band so that blood flow nuances are accurately maintained and reproduced.
11 cl, 4 dwg
