Analog Devices Rational Sample Rate Conversion with Blackfin Processors Application Note

About this manual

This document is an Engineer-to-Engineer Note (EE-183) from Analog Devices that details the theory and implementation of Rational Sample Rate Conversion (SRC). It focuses on applications in digital audio, communications, and speech processing, specifically utilizing Blackfin processors. The text defines SRC as the process of changing a signal's sampling rate, distinguishing between interpolation (increasing the rate) and decimation (decreasing the rate).

What's inside

• Introduction
• Sample Rate Conversion Designs
• Decimation
• Interpolation
• Sample Rate Changes Using Both Interpolation and Decimation
• Sample Rate Conversion by Rational Factor L/M
• Polyphase Filters
• Interpolator-Only Polyphase Filters
• Decimator-Only Polyphase Filters
• Simultaneous Interpolator and Decimator Polyphase Filter

Frequently asked questions

What is the process called when a signal's sampling rate is increased?

Increasing the sampling rate is called interpolation.

How is decimation achieved in terms of sample handling?

It is achieved by discarding every M-1 samples and keeping every Mth sample.

What must be done to the input signal before decimation to prevent aliasing?

The input signal must be lowpass filtered to remove frequency components.