A digital transmit beamformer system with multiple beam transmit capability has a plurality of multi-channel transmitters, each channel with a source of sampled, complex-valued initial waveform information representative of the ultimate desired waveform to be applied to one or more corresponding transducer...http://www.google.de/patents/US6172939?utm_source=gb-gplus-sharePatent US6172939 - Method and apparatus for transmit beamformer system
