An approach to signal processing in an imaging system, for instance an ultrasound medical imaging system, makes use of analog signal processing prior to conversion to digital form, which may be performed in a portable probe of the system. In some examples, the system includes multiple controllable input processing blocks, each implementing a discrete time analog signal processing stage such as time domain filtering for fractional time delay, anti-alias filtering, or matched filtering. The processing blocks may be implemented using a passive charge sharing approach in which charge is transferred between capacitive elements in successive phases using controlled switches.
