Design and construction of a blood flow detector probe for a continuous wave bidireccional doppler ultrasound system

Abstract

THE DESIGN AND CONSTRUCTION OF A BLOOD FLOW DETECTOR PROBE FOR A CONTINUOUS WAVE (CW) BIDIRECTIONAL DOPPLER ULTRASOUND SYSTEM IS PRESENTED. THIS DEVICE IS BASED ON TWO PIEZO ELECTRICCE RAM I CS WORKING IN CONTINUOUS MODE AND USING QUADRATURE PHASE DE MODULATION FOR DETECTING THE BLOOD FLOW DOPPLER SIGNAL. THE PROBE GENERATES THE I (IN PHASE) AND Q (IN QUADRATURE) DOPPLER SIGNALS AS AUDIO. THESE SIGNALS ARE FED TO THE LINE IN ON THE PC SOUND BOARD FOR FURTHER PROCESSING. OSCILLATOR-TRANSMITTER AND DETECTOR-DEMODULATOR CIRCUITS ARE INTEGRATED INTO A 1.5 X 9 CM PRINTED CIRCUIT BOARD (PCB). PI EZO ELECTRICCE -RAM ICS ARE PLACED AND CON NECTED 1 CM APART THE PCB, THIS ACHIEVES NOISE REDUCTION AND INCREASES THE PROBE SENSIBILITY. THE CIRCUIT DESIGN