From e808e015dd84c234f9689daf90aedf0162d7d2f2 Mon Sep 17 00:00:00 2001 From: Andrew Tridgell Date: Wed, 11 Dec 2013 14:14:03 +1100 Subject: LowPassFilter: allow for filtering to be disabled using bandwidth of 0 gives no filtering --- src/lib/mathlib/math/filter/LowPassFilter2p.cpp | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'src/lib/mathlib') diff --git a/src/lib/mathlib/math/filter/LowPassFilter2p.cpp b/src/lib/mathlib/math/filter/LowPassFilter2p.cpp index efb17225d..3699d9bce 100644 --- a/src/lib/mathlib/math/filter/LowPassFilter2p.cpp +++ b/src/lib/mathlib/math/filter/LowPassFilter2p.cpp @@ -46,6 +46,10 @@ namespace math void LowPassFilter2p::set_cutoff_frequency(float sample_freq, float cutoff_freq) { _cutoff_freq = cutoff_freq; + if (_cutoff_freq <= 0.0f) { + // no filtering + return; + } float fr = sample_freq/_cutoff_freq; float ohm = tanf(M_PI_F/fr); float c = 1.0f+2.0f*cosf(M_PI_F/4.0f)*ohm + ohm*ohm; @@ -58,6 +62,10 @@ void LowPassFilter2p::set_cutoff_frequency(float sample_freq, float cutoff_freq) float LowPassFilter2p::apply(float sample) { + if (_cutoff_freq <= 0.0f) { + // no filtering + return sample; + } // do the filtering float delay_element_0 = sample - _delay_element_1 * _a1 - _delay_element_2 * _a2; if (isnan(delay_element_0) || isinf(delay_element_0)) { -- cgit v1.2.3