向高手请教,怎么控制声卡直接产生波形(正弦波)?

Question

向高手请教,windows下怎么控制声卡直接产生波形(正弦波)?
用DirectX,还是I/o,还是嵌汇编?

Answer 1

gzing
用AudioIN组件获取音频数据，再自己画波形。

Answer 2

刚才为你写了个例程,供你参考
unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls,shellApi,mmsystem, TeEngine, Series, ExtCtrls,
  TeeProcs, Chart;
const  BUF_SIZE=100;
  BUF_NUM=10;
type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Chart1: TChart;
    Series1: TFastLineSeries;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
    waveformIn:TWAVEFORMATEX;
    hWaveIn:HWAVEIN;
    pWaveHdr1,pWaveHdr2:PWAVEHDR;
    bEndRecord:boolean;
    Ind:integer;
        Memos:array[0..BUF_NUM-1]of Pointer;
    pBuffer1,pBuffer2:array [0..BUF_SIZE-1] of char;
        pWaveHdrs:array [0..BUF_NUM-1] of  PWAVEHDR;
    procedure mmwimopen(var Msg: TMessage); message MM_WIM_OPEN;
    procedure mmwimdata(var Msg: TMessage); message MM_WIM_DATA;
    procedure mmwimclose(Var Msg:TMessage);message MM_WIM_CLOSE;
     procedure StartSendSound;
     procedure EndSendSound;  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.EndSendSound;
begin
  bEndRecord:=true;
  waveInReset(hwaveIn);
end;procedure TForm1.mmwimclose(var Msg: TMessage);
begin
   waveInUnprepareHeader (hWaveIn, pWaveHdr1, sizeof (WAVEHDR)) ;
   waveInUnprepareHeader (hWaveIn, pWaveHdr2, sizeof (WAVEHDR)) ;
end;procedure TForm1.mmwimdata(var Msg: TMessage);
Var
  pBuffer:Pointer;
  count:integer;
  pSaveBuf:array [0..BUF_SIZE-1] of char;
  i:integer;
begin
  if bEndRecord then
  begin
    WaveInClose(hWaveIn);
    exit;
  end;
  pBuffer:= Pointer(PWAVEHDR(Msg.lParam).lpData);
  count:= (PWAVEHDR(Msg.lParam)).dwBytesRecorded;
  CopyMemory(Addr(pSaveBuf[0]),pBuffer,count);
  if Count>0 then
  for i:=0 to count-1 do
  begin     Series1.addXY(ind,Ord(pSaveBuf[i])-128);
     Inc(ind);
     if Series1.Count>1000 then
       Series1.Delete(0);  end;
  waveInAddBuffer (hWaveIn, PWAVEHDR(Msg.lParam), sizeof (WAVEHDR)) ;
end;procedure TForm1.mmwimopen(var Msg: TMessage);
begin
  waveInAddBuffer(hWaveIn,pWaveHdr1,sizeof(WAVEHDR));
  waveInAddBuffer(hWaveIn,pWaveHdr2,sizeof(WAVEHDR));
  waveInStart(hWaveIn);
end;procedure TForm1.StartSendSound;
begin
   waveformIn.wFormatTag:=WAVE_FORMAT_PCM;
   waveformIn.nChannels:=1;
  // waveformIn.nSamplesPerSec:=11025;
  // waveformIn.nAvgBytesPerSec:=22050;
   waveformIn.nSamplesPerSec:=1000;
   waveformIn.nAvgBytesPerSec:=2000;
   waveformIn.nBlockAlign:=1;
   waveformIn.wBitsPerSample:=16;
   waveformIn.cbSize:=0;
   if WaveInOpen(@hWaveIn,WAVE_MAPPER,@waveformIn,handle,0,CALLBACK_WINDOW)
    <>MMSYSERR_NOERROR then
   begin
     ShowMessage('录音设备打开失败');
   end;
  pWaveHdr1.lpData:=(pBuffer1);
  pWaveHdr1.dwBufferLength:= BUF_SIZE;
  pWaveHdr1.dwBytesRecorded:=0;
  pWaveHdr1.dwUser:=0;
  pWaveHdr1.dwFlags:=0;
  pWaveHdr1.dwLoops:=1;
  pWaveHdr1.lpNext:=nil;
  pWaveHdr1.reserved:=0;
  waveInPrepareHeader(hWaveIn,pWaveHdr1,SizeOf(WAVEHDR));
  pWaveHdr2.lpData:=(pBuffer2);
  pWaveHdr2.dwBufferLength:= BUF_SIZE;
  pWaveHdr2.dwBytesRecorded:=0;
  pWaveHdr2.dwUser:=0;
  pWaveHdr2.dwFlags:=0;
  pWaveHdr2.dwLoops:=1;
  pWaveHdr2.lpNext:=nil;
  pWaveHdr2.reserved:=0;
  waveInPrepareHeader(hWaveIn,pWaveHdr2,SizeOf(WAVEHDR));
  bEndRecord:=false;
end;procedure TForm1.Button1Click(Sender: TObject);
begin
  StartSendSound;
end;procedure TForm1.Button2Click(Sender: TObject);
begin
  EndSendSound;
end;procedure TForm1.FormCreate(Sender: TObject);
var
  i:integer;
begin
  Ind:=0;
  new(pWaveHdr1);
  new(pWaveHdr2);
  for i:=0 to BUF_NUM-1 do
    Memos[i]:=AllocMem(BUF_SIZE);  for i:=0 to BUF_NUM-1 do
  begin
    new(pWaveHdrs[i]);
    pWaveHdrs[i].lpData:=Memos[i];
    pWaveHdrs[i].dwBufferLength:= BUF_SIZE;
    pWaveHdrs[i].dwBytesRecorded:=0;
    pWaveHdrs[i].dwUser:=0;
    pWaveHdrs[i].dwFlags:=0;
    pWaveHdrs[i].dwLoops:=1;
    pWaveHdrs[i].lpNext:=nil;
    pWaveHdrs[i].reserved:=0;
  end;end;
procedure TForm1.FormDestroy(Sender: TObject);
var
  i:integer;
begin
  dispose(pWaveHdr1);
  dispose(pWaveHdr2);
  for i:=0 to BUF_NUM-1 do
  begin
    FreeMem(Memos[i]);
    dispose(pWaveHdrs[i]);
  end;
end;end.