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//------------------------------------------------------------------------------
//This Source Code Form is subject to the terms of the Mozilla Public
//License, v. 2.0. If a copy of the MPL was not distributed with this
//file, You can obtain one at http://mozilla.org/MPL/2.0/.
//------------------------------------------------------------------------------
unit QuickAvg;
{$MODE Delphi}
interface
uses
LCLIntf, LCLType, LMessages, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
Math, SndTypes;
type
TDoubleArray2D = array of array of Double;
TQuickAverage = class(TComponent)
private
FPasses: integer;
FPoints: integer;
FScale: Single;
ReBufs, ImBufs: TDoubleArray2D;
Idx, PrevIdx: integer;
procedure SetPasses(const Value: integer);
procedure SetPoints(const Value: integer);
function DoFilter(V: Single; Bufs: TDoubleArray2D): Single;
protected
{ Protected declarations }
public
constructor Create(AOwner: TComponent); override;
procedure Reset;
function Filter(V: Single): Single; overload;
function Filter(ARe, AIm: Single): TComplex; overload;
function Filter(V: TComplex): TComplex; overload;
function FilteredModule(ARe, AIm: Single): Single;
published
property Passes: integer read FPasses write SetPasses;
property Points: integer read FPoints write SetPoints;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('Snd', [TQuickAverage]);
end;
{ TQuickAverage }
//------------------------------------------------------------------------------
// init
//------------------------------------------------------------------------------
constructor TQuickAverage.Create(AOwner: TComponent);
begin
inherited;
FPoints := 128;
FPasses := 4;
Reset;
end;
procedure TQuickAverage.SetPasses(const Value: integer);
begin
FPasses := Max(1, Min(8, Value));
Reset;
end;
procedure TQuickAverage.SetPoints(const Value: integer);
begin
FPoints := Max(1, Value);
Reset;
end;
procedure TQuickAverage.Reset;
begin
ReBufs := nil;
SetLength(ReBufs, FPasses+1, FPoints);
ImBufs := nil;
SetLength(ImBufs, FPasses+1, FPoints);
FScale := IntPower(FPoints, -FPasses);
Idx := 0;
PrevIdx := FPoints-1;
end;
//------------------------------------------------------------------------------
// filter
//------------------------------------------------------------------------------
function TQuickAverage.Filter(V: Single): Single;
begin
Result := DoFilter(V, ReBufs);
PrevIdx := Idx;
Idx := (Idx + 1) mod FPoints;
end;
function TQuickAverage.Filter(ARe, AIm: Single): TComplex;
begin
Result.Re := DoFilter(ARe, ReBufs);
Result.Im := DoFilter(AIm, ImBufs);
PrevIdx := Idx;
Idx := (Idx + 1) mod FPoints;
end;
function TQuickAverage.Filter(V: TComplex): TComplex;
begin
Result.Re := DoFilter(V.Re, ReBufs);
Result.Im := DoFilter(V.Im, ImBufs);
PrevIdx := Idx;
Idx := (Idx + 1) mod FPoints;
end;
function TQuickAverage.FilteredModule(ARe, AIm: Single): Single;
begin
with Filter(ARe, AIm) do
Result := Sqrt(Sqr(Re) + Sqr(Im));
end;
function TQuickAverage.DoFilter(V: Single; Bufs: TDoubleArray2D): Single;
var
p: integer;
begin
Result := V;
for p:=1 to FPasses do
begin
V := Result;
Result := Bufs[p][PrevIdx] - Bufs[p-1][Idx] + V;
Bufs[p-1][Idx] := V;
end;
Bufs[FPasses,Idx] := Result;
Result := Result * FScale;
end;
end.
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