10 '--------------------------------------------------------------------------
20 ' フーリエ解析プログラム　H21.11.06 T.Tsuji
30 '--------------------------------------------------------------------------
40 CLS 3
50 N=100   'データ数
60 N=N-1
70 DIM X(N)
80 FOR I=0 TO N
90  READ X(I)
100 NEXT I
110 '------------------原波形再生
120 X1=30:Y1=140:Z=4:L1=550/N
130 LINE (X1,Y1-100)-(X1,Y1+100),7
140 LINE (X1,Y1)-(X1+(N+1)*L1,Y1),7
150 PSET (X1,Y1),7
160 FOR I=0 TO N
170  LINE -(X1+I*L1,Y1-X(I)*Z),7
171  circle (x1+I*L1,y1-x(i)*z),3
180 NEXT I
190 '-------------------フーリエ級数　計算
200 PI=3.141592#
210 DT=PI*2/N
220 INPUT "次数:";M
230 DIM C1(M),C2(M),C(M)
240 FOR NN=0 TO M
250  C1(NN)=0:C2(NN)=0
260 NEXT NN
270 FOR NN=0 TO M
280  FOR I=0 TO N
290   C1(NN)=C1(NN)+DT/PI*X(I)*COS(NN*I*DT)
300   C2(NN)=C2(NN)+DT/PI*X(I)*SIN(NN*I*DT)
310   C(NN)=SQR(C1(NN)^2+C2(NN)^2)
320  NEXT I
330 NEXT NN
340 '----------------パワースペクトル表示
350 X0=30:Y0=370:Z2=5:L=8
360 LINE (X0-1*Z2,Y0)-(X0+(M+5)*L ,Y0),7
370 FOR I=0 TO M
380  LINE (X0+I*L,Y0-2)-(X0+I*L,Y0+2),7
390 NEXT I
400 PSET(X0,Y0),7
410 FOR I=0 TO M
420  LINE -(X0+I*L ,Y0-C(I)*Z2),6
430 NEXT I
431 'n$="s"
432 'n$=inkey$ : if n$=" " then 440 else 431
440 '---------------波形を再生
441 for i=0 to N
442	circle (x1+I*L1,y1-x(i)*z),3,0
443 next i
450 LNG=360
460 DIM XP(LNG)
470 L3=550/LNG
480 DT=2*PI/LNG
490 FOR I= 0 TO LNG
500  XP=0
510  FOR NN=1 TO M
520   XP=XP+C1(NN)*COS(NN*I*DT)+C2(NN)*SIN(NN*I*DT)
530  NEXT NN
540  XP(I)=XP+C1(0)/2
550 NEXT I
560 PSET (X1,Y1)
570 '-------------再生波形描画
580 FOR I=0 TO LNG
590  LINE -(X1+I*L3,Y1-XP(I)*Z),3
600 NEXT I
610 END
620 '-------------------原波形データ
630 DATA 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10
640 DATA -10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10
650 data 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10
660 data -10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10