How FPGA Decimation FIR Filters Work in Software-Defined Radio Systems

Описание: Decimation FIR filters are a critical building block in modern software-defined radios (SDRs).

In this video, Dr. Paul Kerstetter walks through why decimation filters are essential, how they fit into an FM SDR signal chain, and how to design them efficiently for FPGA implementation.

We start with a high-level overview of an FM software-defined radio, showing how an oversampled ADC, mixers, and quadrature (I/Q) channels work together inside an FPGA. From there, we explore why a single low-pass FIR filter at a very high sampling rate is impractical—and how multi-stage decimation dramatically reduces filter complexity.

Along the way, you’ll learn:
• Why decimation filters are needed in SDR systems
• How FIR filters arise from convolution and LTI system theory
• How filter requirements (sampling rate, transition band, ripple, attenuation) affect the number of coefficients
• Why transition bandwidth relative to sampling frequency dominates FIR complexity
• How multi-stage decimation reduces tens of thousands of taps down to a few hundred
• How Nyquist’s sampling theorem justifies safe sample-rate reduction

Dr. Kerstetter uses TFilter, a free FIR filter design tool, to illustrate key design tradeoffs, and then demonstrates how to implement decimation FIR filters using Vivado’s FIR Compiler IP.
The video concludes with a practical, FPGA-friendly multi-stage decimation filter chain suitable for FM broadcast receivers.

This presentation is ideal for FPGA designers, SDR enthusiasts, and engineers looking to understand FIR decimation filters from both a theoretical and practical perspective.

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Hashtags
#FIRFilters #DecimationFilters #SoftwareDefinedRadio #SDR
#FPGA #DigitalSignalProcessing #DSP