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サンプル波形の生成
OPTION CHARACTER BYTE
LET CHANNEL=1 !'モノラル
LET SAMPLEBIT=16 !'ビット数
LET HEADERSIZE=16
LET WAVETYPE=1
!'LET PATH$="C:\WINDOWS\TEMP\" !'作業用フォルダ、RAMディスクなど
DIM A$(7),FR(6),TYPE$(8)
MAT READ A$
DATA "8kHz","11.25kHz","22.5kHz","32kHz","44.1kHz","48kHz","プログラム終了"
MAT READ FR
DATA 8000,11025,22050,32000,44100,48000
MAT READ TYPE$
DATA 正弦波,三角波,方形波,台形波,のこぎり波,階段状,パルス波,ワイヤストラス
DO
LOCATE CHOICE (A$):MODE
IF MODE=7 THEN STOP
LOCATE VALUE ,RANGE 0 TO FR(MODE)/2 ,AT 440 : FREQ
SELECT CASE MODE !'サンプリング周波数
CASE 1
LET SAMPLINGFREQ=8000
CASE 2
LET SAMPLINGFREQ=11025
CASE 3
LET SAMPLINGFREQ=22050
CASE 4
LET SAMPLINGFREQ=32000
CASE 5
LET SAMPLINGFREQ=44100
CASE 6
LET SAMPLINGFREQ=48000
END SELECT
LOCATE CHOICE (TYPE$):MODE
LET SAMPLESIZE = SAMPLEBIT / 8 * CHANNEL
LET DATARATE = SAMPLESIZE * SAMPLINGFREQ
LET VOL=.1 !'音量 ※スピーカ破損の可能性あり。音量に気をつけること
LET LEVEL=2^(SAMPLEBIT-1)*VOL
LET SECOND=3 !'再生時間(3秒間)
!' LOCATE VALUE ,RANGE 1 TO 10,AT 3 : SECOND
LET PCMSIZE=INT(DATARATE*SECOND)
LET WAVEFILESIZE = PCMSIZE + 36
OPEN #1:NAME PATH$ & TYPE$(MODE) & ".wav"
ERASE #1
PRINT #1:"RIFF";
PRINT #1:MKL$(WAVEFILESIZE);
PRINT #1:"WAVEfmt ";
PRINT #1:MKL$(HEADERSIZE);
PRINT #1:MKI$(WAVETYPE);
PRINT #1:MKI$(CHANNEL);
PRINT #1:MKL$(SAMPLINGFREQ);
PRINT #1:MKL$(DATARATE);
PRINT #1:MKI$(SAMPLESIZE);
PRINT #1:MKI$(SAMPLEBIT);
PRINT #1:"data";
PRINT #1:MKL$(PCMSIZE);
FOR I=0 TO INT(SAMPLINGFREQ*SECOND)-1
LET X=I*FREQ/SAMPLINGFREQ*2*PI
SELECT CASE MODE
CASE 1
LET DAT=SIN(X)
CASE 2
LET DAT=TRIANGLEW(X)
CASE 3
LET DAT=SQUAREW(X)
CASE 4
LET DAT=TRAPEZOIDALW(X)
CASE 5
LET DAT=SAW(X)
CASE 6
LET DAT=STEPWISE(X,4)
CASE 7
LET DAT=PULSEW(X)
CASE 8
LET DAT=WEIERSTRASS(X,15)
END SELECT
LET DAT=DAT*LEVEL
PRINT #1:MKI$(INT(DAT));
NEXT I
CLOSE #1
PLAYSOUND PATH$ & TYPE$(MODE) & ".wav" !'再生
!'FILE DELETE PATH$ & TYPE$(MODE) & ".wav"
LOOP
END
EXTERNAL FUNCTION PULSEW(X) !'パルス波 PULSE WAVE
IF ABS(ABS(SIN(X))-1)<.0001 THEN LET PULSEW=SGN(SIN(X)) ELSE LET PULSEW=0
END FUNCTION
EXTERNAL FUNCTION SQUAREW(X) !'方形波 SQUARE WAVE
LET SQUAREW=SGN(SIN(X))
END FUNCTION
EXTERNAL FUNCTION TRIANGLEW(X) !'三角波 TRIANGLE WAVE
LET NN=MOD(X,PI)
IF NN>PI/2 THEN LET NN=PI-NN
LET TRIANGLEW=NN/(PI/2)*SGN(SIN(X))
END FUNCTION
EXTERNAL FUNCTION SAW(X) !'のこぎり波
LET SAW=MOD(X,PI)/(PI/2)-1
END FUNCTION
EXTERNAL FUNCTION TRAPEZOIDALW(X) !'台形波 TRAPEZOIDAL WAVE
LET NN=X-INT(X/PI)*PI
IF NN>PI/2 THEN LET NN=PI-NN
LET TRAPEZOIDALW=MIN(1,MAX(-1,NN*SGN(SIN(X))) )
END FUNCTION
EXTERNAL FUNCTION STEPWISE(X,NN) !'階段状
LET STEPWISE=INT(NN*(SIN(X)+1))/NN-1
END FUNCTION
EXTERNAL FUNCTION WEIERSTRASS(X,N) !'ワイヤストラス
LET B=11
FOR I=0 TO N
LET S=S+.5^(I+1)*SIN(B^I*X)
NEXT I
LET WEIERSTRASS=S
END FUNCTION
EXTERNAL FUNCTION MKI$(A)
OPTION CHARACTER BYTE
DECLARE STRING A$,B$
IF A<0 THEN LET A=A+65536
LET A$=CHR$(MOD(A,256))
LET B$=CHR$(INT(A/256))
LET MKI$=A$ & B$
END FUNCTION
EXTERNAL FUNCTION MKL$(A)
OPTION CHARACTER BYTE
DECLARE STRING A$,B$,C$,D$
IF A<0 THEN LET A=A+2^32
LET A$=CHR$(MOD(A,256))
LET B$=CHR$(MOD(INT(A/256),256))
LET C$=CHR$(MOD(INT(A/65536),256))
LET D$=CHR$(MOD(INT(A/16777216),256))
LET MKL$=A$ & B$ & C$ & D$
END FUNCTION
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