1//============================================================================
2//
3// SSSS tt lll lll
4// SS SS tt ll ll
5// SS tttttt eeee ll ll aaaa
6// SSSS tt ee ee ll ll aa
7// SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
8// SS SS tt ee ll ll aa aa
9// SSSS ttt eeeee llll llll aaaaa
10//
11// Copyright (c) 1995-2019 by Bradford W. Mott, Stephen Anthony
12// and the Stella Team
13//
14// See the file "License.txt" for information on usage and redistribution of
15// this file, and for a DISCLAIMER OF ALL WARRANTIES.
16//============================================================================
17
18#include "bspf.hxx"
19#include "HighPass.hxx"
20
21// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
22HighPass::HighPass(float cutOffFrequency, float frequency)
23 : myLastValueIn(0),
24 myLastValueOut(0),
25 myAlpha(1.f / (1.f + 2.f*BSPF::PI_f*cutOffFrequency/frequency))
26{
27}
28
29// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
30float HighPass::apply(float valueIn)
31{
32 float valueOut = myAlpha * (myLastValueOut + valueIn - myLastValueIn);
33
34 myLastValueIn = valueIn;
35 myLastValueOut = valueOut;
36
37 return valueOut;
38}
39