Ultrasonic Imaging System Using Spatial and Temporal M-Sequences

Abstract

A new ultrasonic imaging system combining temporal modulation of the ultrasonic signal by an M-sequence with spatial modulation of the wave field by a rotating M-sequence phase disk has been developed. This system uses neither beam forming nor transducer scanning, and has high resolution both in range and azimuth. The correlation function of the temporal M-sequence determines the range resolution, while the azimuth resolution is determined by the configuration of the rotating M-sequence phase disk. The use of the M-sequence modulations also results in images with high signal-to-noise ratio.