Generalised dynamic decimation method using polyphase MACs for ultrasound imaging

In medical ultrasound imaging, the focused echo signal is decimated with a finite impulse response filter by a rational factor M/L, the frequency response of which dynamically changes over time. Presented is, an efficient structure for dynamic decimation by a programmable rational factor that use a fixed number of polyphase multiplier-accumulators (MACs) regardless of the values of M and L. The proposed structure uses the minimum number of MAC units operating at the input data rate to minimise both power consumption and hardware complexity.