A coherent imaging system having a phased array of transmit elements provides for transmit apodization (or weighting) by controlling pulse width of the transmit pulses on every channel. Conventional transmit apodization requires a channel-by-channel voltage (or current) control which, because of its...http://www.google.com.au/patents/US6135963?utm_source=gb-gplus-sharePatent US6135963 - Imaging system with transmit apodization using pulse width variation
