CATFilterEWMA.h

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/// \file CATFilterEWMA.h
/// \brief Exponentially weighted moving average filter (EWMA / Low pass)
/// \ingroup CAT
///
/// f(x) = coef * f(x-1) + (1-coef) * x
///
/// Copyright (c) 2002-2008 by Michael Ellison.
/// See COPYING.txt for the \ref gaslicense License (MIT License).
///
// $Author: mikeellison $
// $Date: 2008-01-19 19:19:35 -0600 (Sat, 19 Jan 2008) $
// $Revision:   $
// $NoKeywords: $
//---------------------------------------------------------------------------
#ifndef _CATFilterEWMA_H_
#define _CATFilterEWMA_H_

#include "CATFilter.h"

/// \class CATFilterEWMA
/// \brief Exponentially weighted moving average filter (EWMA / Low pass)
/// \ingroup CAT
///
/// f(x) = coef * f(x-1) + (1-coef) * x
///
class CATFilterEWMA : public CATFilter
{
    public:
        /// CATFilterEWMA() - constructor for EWMA filter
        ///
        /// \param coefficient - filter coefficient. High values = slower movement.
        CATFilterEWMA(CATFloat32 coefficient);

        virtual ~CATFilterEWMA();

        /// SetCoefficient() sets the filter coefficient.
        ///
        /// \param coef - filter coefficient     
        void      SetCoefficient( CATFloat32 coef);

        CATFloat32 GetCoefficient();

        /// Filter() - add a value and get the next one
        inline CATFloat32 Filter( CATFloat32 rawVal )
        {           
            fLastFiltered = CATTruncDenormals((fCoef * fLastFiltered) + (1.0f - fCoef) * rawVal);
            return fLastFiltered;
        }

    protected:
        CATFloat32  fCoef;
};


#endif //_CATFilterEWMA_H_

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