In ultrasound phased-array imaging systems the receiver directivity pattern is steered by controlling the delay of echoes from the array elements. A new processing technique is introduced that provides the required delay first by properly phasing the echo carrier, and successively by delaying the echo envelope. This latter operation is based on a new analogue sampled-data delay-line. Independent control of phase delay offers a simple means of compensating for random phase errors due to non-uniformity of the array elements response.