Sampling-point-wise digital dynamic focusing in the receive mode of an ultrasonic linear array imaging system

An ultrasonic linear array system has been developed in which dynamic focusing in the receive mode is performed in a digital fashion at every sampling point. In order to reduce the sampling rate, the analytic signal sampling technique is employed and the required Hilbert transformer is realized by analog 90° phase shifters. An ASIC chip for digital focusing which includes variable sampling clock generators and digital delay devices and adders, has been developed. The experimental results show a proper operation of the system