What is a cascaded integrator and comb filter?
In digital signal processing, a cascaded integrator–comb (CIC) is an optimized class of finite impulse response (FIR) filter combined with an interpolator or decimator. A CIC filter consists of one or more integrator and comb filter pairs.
How is a cascaded integrator used in a decimating CIC?
In the case of a decimating CIC, the input signal is fed through one or more cascaded integrators, then a down-sampler, followed by one or more comb sections (equal in number to the number of integrators). An interpolating CIC is simply the reverse of this architecture, with the down-sampler replaced with a zero-stuffer (up-sampler).
Who is the inventor of the CIC filter?
CIC filters were invented by Eugene B. Hogenauer, and are a class of FIR filters used in multi-rate digital signal processing. The CIC filter finds applications in interpolation and decimation.
Can a CIC filter be reconfigured for different rates?
Additionally, CIC filters can typically be reconfigured for different rates by changing nothing more than the decimation/interpolation section assuming the bit width of the integrators and comb sections meets certain mathematical criteria based on the maximum possible rate change.
How are Combs and integrators used in CIC?
The conventional CIC structure is obtained by cascading identical moving average filters, then rearranging the sections to place all integrators first (decimator) or combs first (interpolator). Such rearrangement is possible because both combs and integrators are LTI.
What does the comb stage of a CIC filter do?
The feedforward portion of the CIC filter is called the comb section, whose differential delay is D , while the feedback section is typically called an integrator . The comb stage subtracts a delayed input sample from the current input sample, and the integrator is simply an accumulator.
What is the cascade structure of a CIC filter?
If we condense the delay-line representation and ignore the 1/ D scaling in Figure 2b we obtain the classic form of a 1st-order CIC filter, whose cascade structure is shown in Figure 2c. The feedforward portion of the CIC filter is called the comb section, whose differential delay is D, while the feedback section is typically called an integrator.