Summary

The blog explains how Cascade-Integrator-Comb (CIC) interpolators and decimators produce spectral images and aliases when changing sample rates, and shows practical ways to compute and visualize those images. Readers will learn analysis techniques (FFT-based and polyphase perspectives) and practical guidance for compensation and fixed-point implementation issues.

Key Takeaways

• Compute the spectral images produced by CIC decimation and interpolation using FFT-based analysis.
• Predict aliasing locations and relative amplitudes from the CIC order and rate-change factor.
• Design and position simple FIR compensation filters to correct CIC passband droop and reduce imaging artifacts.
• Apply a polyphase/multirate viewpoint to model CIC behavior and simplify image computation.
• Estimate fixed-point register growth and scaling requirements for practical CIC implementations.

Who Should Read This

DSP engineers and advanced students familiar with sampling-rate conversion who need to analyze, visualize, or mitigate spectral imaging and aliasing caused by CIC interpolators/decimators.

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