Cascaded Integrator-comb Filter - The CIC Filter

The CIC Filter

CIC filters were invented by Eugene B. Hogenauer, and are a class of FIR filters used in multi-rate processing. The CIC filter finds applications in interpolation and decimation. Unlike most FIR filters, it has a decimator or interpolator built into the architecture. The figure at the right shows the Hogenauer architecture for a CIC Interpolator.

The system function for the composite CIC filter referenced to the high sampling rate, fs is:

\begin{align} H(z) &=\left ^N \\ &= \left ( \frac{1-z^{-RM}}{1-z^{-1}} \right ) ^N \end{align}

Where:

R = decimation or interpolation ratio
M = number of samples per stage (usually 1 but sometimes 2)
N = number of stages in filter

Characteristics of CIC Filters

  1. Linear phase response;
  2. Utilize only delay and addition and subtraction; that is, it requires no multiplication operations;

Read more about this topic:  Cascaded Integrator-comb Filter