Implementing a CIC Filter with Decimation Factor of 4 in MATLAB

This implementation involves designing a CIC (Cascaded Integrator-Comb) filter in MATLAB with a decimation factor of 4, enabling simultaneous signal filtering and downsampling. CIC filters are highly efficient digital filters widely used in signal processing and communication systems due to their simplicity and low resource requirements. The filter operates through iterative integration and comb stages, reducing computational complexity and memory usage. Key implementation steps include: 1. Defining filter parameters such as decimation factor (R=4), number of stages (N), and differential delay (M). 2. Structuring the filter using integrator and comb sections, where the integrator operates at the input sample rate and the comb operates at the decimated rate. 3. Implementing the difference equation for the comb stage: y[n] = x[n] - x[n - M], and the integration stage: y[n] = y[n-1] + x[n]. 4. Using MATLAB functions like cicdecimator for design and frequency response analysis via freqz. Performance optimization involves selecting appropriate stages to balance passband ripple and aliasing rejection. The resulting filter can be validated through frequency domain analysis and testing with sample input signals to ensure compliance with design specifications.