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Scilab help >> Signal Processing > remez

# remez

### 呼び出し手順

`an=remez(guess,mag,fgrid,weight)`

guess

fgrid

mag

weight

an

### 説明

`h = sum[a(i)*cos(weight)], i=1:n`

FIR, 線形位相フィルタは以下のコマンドにより得られた `remez`の出力から得ることができます:

```hn(1:nc-1)=an(nc:-1:2)/2;
hn(nc)=an(1);
hn(nc+1:2*nc-1)=an(2:nc)/2;```

この関数は主にremezb関数によりコールされることを 意図しています.

### 参考文献

E.W. Cheney, Introduction to Approximation Theory, McGraw-Hill, 1966

http://en.wikipedia.org/wiki/Remez_algorithm

### 参考文献

この関数は以下の文献で書かれたFortranコード`remez.f` に基づいています:

• James H. Mcclellan, department of electrical engineering and computer science, Massachusetts Institute of Technology, Cambridge, Massachussets. 02139

• Thomas W. Parks, department of electrical engineering, Rice university, Houston, Texas 77001

• Thomas W. Parks, department of electrical engineering, Rice university, Houston, Texas 77001

### 例

```nc=21;
ngrid=nc*250;
fgrid=.5*(0:(ngrid-1))/(ngrid-1);
mag(1:ngrid/2)=ones(1:ngrid/2);
mag(ngrid/2+1:ngrid)=0*ones(1:ngrid/2);
weight=ones(fgrid);
guess=round(1:ngrid/nc:ngrid);
guess(nc+1)=ngrid;
guess(nc+2)=ngrid;
an=remez(guess,mag,fgrid,weight);```

### 参照

• remezb — 振幅応答のミニマックス近似
• eqfir — FIRフィルタのミニマックス近似