| 摘要 |
PURPOSE:To detect the velocity of an object from a low velocity up to a high velocity more accurately by providing an angle correcting means to correct the angular difference or a means to shift the angular reference axis to + or -pidirections when the addition of phase difference vectors is carried out. CONSTITUTION:Ultrasound pulses emitted from a wave transmitting circuit 2 are transmitted toward a reflector 11 repeatedly under a constant time interval from an ultrasound transducer 1. Ultrasound pulses reflected from the reflector 11 are received with a wave receiving circuit 3. The outputs of a phase comparator 4 relating to the reflector 11, Vn=Anexp(jthetan), are inputted to a velocity detecting section 7 to obtain the output DELTAthetaA of an angle correcting circuit 720. In a divisional unit 8, the output DELTAthetaA of the velocity detecting section 7 is divided by the transmitting interval T of the ultrasound pulses. The result is the Doppler frequency omegad, that is omegad=DELTAthetaA/T. |
