FIR Filter Library
mikroPascal PRO for dsPIC30/33 and PIC24 includes a library for finite impulse response (FIR) filter. All routines work with fractional Q15 format.
A finite impulse response (FIR) filter is a type of a digital filter, whose impulse response (the filter's response to a delta function) is finite because it settles to zero in a finite number of sample intervals.
Library Routines
FIR_Radix
Prototype |
function FIR_Radix(FilterOrder: word; ptrCoeffs: longint; BuffLength: word; ptrInput: word; Index: word): word; |
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Description |
This function applies FIR filter to |
Parameters |
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Returns |
with : N - buffer length
k - current index
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Requires |
Nothing. |
Example |
const BUFFFER_SIZE = 32; const FILTER_ORDER = 20; const COEFF_B[FILTER_ORDER+1] of integer = ( 0x0000, 0x0048, 0x0133, 0x02D3, 0x052B, 0x0826, 0x0BA0, 0x0F62, 0x1329, 0x16AA, 0x199A, 0x16AA, 0x1329, 0x0F62, 0x0BA0, 0x0826, 0x052B, 0x02D3, 0x0133, 0x0048, 0x0000 ); var input: array[BUFFFER_SIZE] of word; ydata; // Input buffer inext: word; // Input buffer index ... var CurrentValue: word; CurrentValue := FIR_Radix(FILTER_ORDER+1, // Filter order word(@COEFF_B), // B coefficients of the filter BUFFFER_SIZE, // Input buffer length word(@input), // Input buffer inext); // Current sample |
Notes |
Input samples must be in Y data space. |
Copyright (c) 2002-2012 mikroElektronika. All rights reserved.
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