July 2007

Rev 1

1/18

18

AN2182

Application note

Filters using the ST10 DSP library

Introduction

The ST10F2xx family provides a 16-bit multiply and accumulate unit (MAC) allowing control-oriented

signal processing and filtering widely used in digital applications.

An ST10 DSP software library, developed by STMicroelectronics, contains a set of basic arithmetic

operations such as multiplication as well as two main filter functions, FIR (finite impulse response) and IIR

(infinite impulse response), mainly used in digital signal processing.

The first chapter of this application note describes a theoretical digital implementation of four different

filters:

■

Low-pass filter

■

High-pass filter

■

Passband filter

■

Cut-band filter

The method adopted for each filter is the approximation of the ideal filter model by a FIR filter. This theory

aims to compute the FIR’s coefficients by truncating the real signal with a known window.

The second chapter illustrates a practical implementation of a low-pass filter using the ST10 DSP library,

its results and its limitations.

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