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Introduction to DSP

Programming a DSP processor

A simple FIR filter

The simple FIR filter equation:

can be implemented quite directly in C language:

y[n] = 0.0;
for (k = 0; k < N; k++)
y[n] = y[n] + c[k] * x[n-k];

But this naive code is inefficient:

The code is inefficient because:

• it uses array indices [i] rather than pointers *ptr
• it needs a lot of address arithmetic
• it repeatedly accesses the output array

| Last updated: 13th January 1997 | http://www.bores.com/courses/intro/program/7_filter.htm

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