[Introduction of Software Defned Ultrasound System's Hardware Architecture]. 
This article introduces a kind of ultrasound system, named as software defined ultrasound.  This system realizes the signal processing by software based on RF (Radio Frequency) data and realizes the real focus-by-point in beamforming.  This architecture discards the hardware digital signal processors.  It can lower the cost and reduce the design complexity.  The architecture also can make system update and maintenance easier.