FIRFilter.h File Reference

FIR (Finite Impulse Response) filter with windowed-sinc coefficient design. More...

#include "AudioBuffer.h"
#include "SimdOps.h"
#include "WindowFunctions.h"
#include <algorithm>
#include <atomic>
#include <cassert>
#include <cmath>
#include <numbers>
#include <span>
#include <vector>

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Classes
class	dspark::FIRDesign< T >
	Static methods for designing FIR filter coefficients. More...
class	dspark::FIRFilter< T >
	FIR filter using direct-form convolution with a mirrored delay line. More...

Namespaces
namespace	dspark
	Main namespace for the DSPark framework.

Detailed Description

FIR (Finite Impulse Response) filter with windowed-sinc coefficient design.

FIR filters provide linear phase response – they do not distort the phase of the signal. This makes them essential for:

• Mastering-grade equalisation
• Linear-phase crossovers
• Sample rate conversion (anti-aliasing)
• Any application where phase accuracy matters

Trade-offs vs IIR (Biquad):

	IIR (Biquad)	FIR
Phase	Non-linear	Linear (symmetric)
Efficiency	Very few coefficients	Many coefficients needed
Latency	Minimal	N/2 samples
Stability	Always stable	Always stable

For short FIR filters (<= ~256 taps), direct convolution is used via the FIRFilter class, which features a lock-free ping-pong coefficient publish for safe real-time updates and SIMD (simd::dotProduct) convolution.

Coefficient design (FIRDesign) always runs its maths in double precision and casts to T on return: design is setup-time work, so float builds get full float accuracy for free.

Dependencies: WindowFunctions.h, SimdOps.h, AudioBuffer.h.

Definition in file FIRFilter.h.