Notes on Digital Signal Processing: Practical Recipes for Design, Analysis and Implementation

Note 57. Polyphase Interpolators

A1-to-L interpolator can be implemented using the polyphase structure shown in Figure 57.1. If h[n] is the response for the interpolation filter when implemented in one of the conventional single-stage structures presented in Note 32, then each individual p_ρ[n] in Figure 57.1 is a different down sampled version of h[n] obtained as

57.1

for

n = 0, 1, 2,..., (N/L –1)

ρ = 0, 1, 2,...,(L – 1)

Figure 57.1. A 1-to-L interpolator implemented using a polyphase structure with a commutator

57.1. Why It Works

Consider ...