Cic ip core functional description, Cic ip core functional description -1 – Altera CIC MegaCore Function User Manual
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CIC IP Core Functional Description
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2014.12.15
UG-CIC
You can select either a decimation or interpolation CIC filter. A decimation CIC filter comprises a
cascade of integrators (integrator), followed by a down sampling block (decimator) and a cascade of
differentiators (called the differentiator or comb section). Similarly an interpolation CIC filter comprises a
cascade of differentiators, followed by an up sampling block (interpolator) and a cascade of integrators.
In a CIC filter, both the integrator and comb sections have the same number of integrators and differen‐
tiators. Each pairing of integrator and differentiator is a stage. The number of stages (N) has a direct effect
on the frequency response of a CIC filter. You determine the response of the filter by configuring:
• The number of stages N
• The rate change factor R
• The number of delays in the differentiators (differential delay) M. Generally, set the differential delay
to 1 or 2.
Figure 3-1: Three-stage CIC Decimation Filter Frequency Response
CIC decimation filter with N = 3, M = 2 and R = 32
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