SignalUtils::FirFilter Function

SignalUtils Namespace

Overload List

#SignatureDescription
1void FirFilter(TVec *Src, TVec *Dst, TFirState &FIRState);Filter data with a FIR filter.
2void FirFilter(const double Src, double &Dst, TFirState &FIRState);Filter data with a FIR filter.
3void FirFilter(const TCplx &Src, TCplx &Dst, TFirState &FIRState);Filter data with a FIR filter.
4void FirFilter(TVec *Data, TVec *FirTaps, int UpSample = 1, int DownSample = 1);Filter Data with a FIR filter and place the result back in the Data.

Overload 1: void FirFilter(TVec *Src, TVec *Dst, TFirState &FIRState);

Filter data with a FIR filter.

#NameTypeDescription
1SrcTVec *
2DstTVec *
3FIRStateTFirState &
Remarks:

Filter data in Src and place the result in Dst. FirState must be initialized with a call to FirInit. This version of FirFilter routine can filter streaming blocks of data.

Examples
#include "MtxExpr.h"
#include "Units.OptimalFIR.h"
#include "Units.SignalUtils.h"

using namespace Dew;
using namespace Dew::Math;
using namespace Dew::Signal;
using namespace Dew::Signal::Units::OptimalFir;
using namespace Dew::Signal::Units::SignalUtils;

void Example()
{
    Vector b, c, Response, Response1, H;
    TFirState State;
    int n, i;
    double FS;

    FS = 2;
    Tone(b, 300, 6.0/300, 0, 1);

    //   Alternative: try gaussian noise
    //    b = RandGauss(300, TMtxFloatPrecision::mvDouble);

    c.Size(b);
    RemezImpulse(H, DewArray<double>{0.5, 0.7}, 0.001, TFilterType::ftLowpass, 1, FS);
    State = TFirState();
    FirInit(H, State);
    //Alternative 1, FIR streaming
    n = 10;
    int bLength = b.Length;
    for (i = 0; i <= (bLength / n) - 1; i++)
    {
        b.SetSubRange(i*n, n);
        c.SetSubRange(i*n, n);
        FirFilter(b, c, State);
    }

    //Alternative 2 single block filter (does not require TIirState)
    //                c.Copy(b);
    //                FirFilter(c, H);

    //Alternative 3 single block
    //                FirFilter(b, c, State);

    c.SetFullRange();
    b.SetFullRange();
    FrequencyResponse(b, nullptr, Response, 8, true, TSignalWindowType::wtHanning);
    FrequencyResponse(c, nullptr, Response1, 8, true, TSignalWindowType::wtHanning);
    FirFree(State);
}
Declared in Dew::Signal::Units::SignalUtils · Dew.Signal/Units.SignalUtils.h · Cross-compiler

Overload 2: void FirFilter(const double Src, double &Dst, TFirState &FIRState);

Filter data with a FIR filter.

#NameTypeDescription
1Srcconst double
2Dstdouble &
3FIRStateTFirState &
Remarks:

Filter real Src sample and place the filtered result in Dst sample.

Declared in Dew::Signal::Units::SignalUtils · Dew.Signal/Units.SignalUtils.h · Cross-compiler

Overload 3: void FirFilter(const TCplx &Src, TCplx &Dst, TFirState &FIRState);

Filter data with a FIR filter.

#NameTypeDescription
1Srcconst TCplx &
2DstTCplx &
3FIRStateTFirState &
Remarks:

Filter real TCplx sample and place the filtered result in Dst sample.

Declared in Dew::Signal::Units::SignalUtils · Dew.Signal/Units.SignalUtils.h · Cross-compiler

Overload 4: void FirFilter(TVec *Data, TVec *FirTaps, int UpSample = 1, int DownSample = 1);

Filter Data with a FIR filter and place the result back in the Data.

#NameTypeDescription
1DataTVec *
2FirTapsTVec *
3UpSample = 1int
4DownSample = 1int
Remarks:

This version of FirFilter can not be used to filter streaming data. The routine compensates for group delay and returns filtered data delayed by 0 (odd FIR length) or 0.5 samples (even FIR length).

Examples
#include "MtxExpr.h"
#include "Units.OptimalFIR.h"
#include "Units.SignalUtils.h"

using namespace Dew;
using namespace Dew::Math;
using namespace Dew::Signal;
using namespace Dew::Signal::Units::OptimalFir;
using namespace Dew::Signal::Units::SignalUtils;

void Example()
{
    Vector b(0);
    Vector c(0);
    Vector h(0);
    Vector Response1(0);
    Vector Response2(0);
    TFirState state;
    int n;
    int i;
    double FS = 2;

    Tone(b, 300, 6.0/300, 0, 1, false);

    //   Alternative: try gaussian noise
    //    b = RandGauss(300, TMtxFloatPrecision::mvDouble);

    c.Size(b);
    RemezImpulse(h, DewArray<double>{0.5, 0.7}, 0.001, TFilterType::ftLowpass, 1, FS, false);
    FirInit(h, state, 1, 0, 1, 0);
    //Alternative 1, FIR streaming
    n = 10;
    int bLength = b.Length; //to prevente reevaluaton inside "for"
    for (i = 0; i < (bLength/n); i++)
    {
        b.SetSubRange(i*n, n);
        c.SetSubRange(i*n, n);
        FirFilter(b, c, state);
    }
    c.SetFullRange();
    b.SetFullRange();
    FirFree(state);

    //Alternative 2 single block filter (does not require TFirState)
    //                c.Copy(b);
    //                FirFilter(c, h, 1, 1);

    //Alternative 3 single block
    //                c.Copy(b);
    //                FirFilter(b, c, state);

    FrequencyResponse(b, nullptr, Response1, 1, true, TSignalWindowType::wtHanning, 0);
    FrequencyResponse(c, nullptr, Response2, 1, true, TSignalWindowType::wtHanning, 0);
}
See Also: SignalUtils::FirInit, SignalUtils::FirFilter
Declared in Dew::Signal::Units::SignalUtils · Dew.Signal/Units.SignalUtils.h · Cross-compiler