Ultrasonic device comprising an active impedance matching device between an ultrasonic transducer and the generator for generating pulse signals for the transducer

摘要

An ultrasonic active impedance matching device between an ultrasonic transducer and a generator of pulses includes an interface stage (100) and a matching stage (200) which are connected by way of a coaxial cable (150) having an impedance of 50 ohms. The interface stage (100) has a sub- assembly (10, 11, 12, 13, 14) for generating a d.c. signal having an amplitude which is proportional to but smaller than the peak value of the pulses, a sub-assembly (15, 16, 17 50) for generating a low-voltage pulse which is matched with the impedance of the cable, and a programmable power supply (18) for producing a d.c. voltage which is applied to the transducer via the cable. The matching stage (200) has a sub-assembly (19) for transmitting the excitation pulse of the transducer (2) and a receiving sub-assembly (20, 21) for returning the echographic signal to the generator (1) via the cable (150).