CLS
PRINT "F0URIER SERIES EXPANSION OF "
PRINT "PIECEWISE LINEAR PERIODIC FUNCTIONS"
REM ==INPUT DATA==
DIM A(10)
DIM B(10)
GOSUB [SIZE]
REM ==COMPUTE COEFFICIENTS==
GOSUB [FOFIZE]
GOSUB [NIZEZE]
GOTO [ONONEIZE]
[SIZE]
PRINT
PRINT "FUNCTION PARAMETER INPUT"
PRINT
INPUT "PERIOD = ";T
PRINT
INPUT "NUMBER OF SEGMENTS = ";N
PRINT
PRINT "DESIRED NUMBER OF"
INPUT "TERMS IN EXPANSION = ";M
REM ==INITIALIZE VARIABLES==
P1 = 3.141592654
P2 =2 * P1
W0 = P2 / T
A0 = 0
FOR I = 1 TO M
A(I) = 0
B(I) = 0
NEXT I
RETURN
REM ==INPUT SEGMENT DATA==
[FOFIZE]
PRINT
PRINT
PRINT "ENTER VERTEX COORDINATES"
PRINT
PRINT "X , F(X)"
PRINT "(IN ORDER OF INCREASING X)"
PRINT
PRINT "VERTEX 1"
INPUT "X = ";X0
INPUT "F = ";F0
K = 0
[FISIZE]
K = K + 1
REM ==CHECK F0R LAST SEGMENT==
IF K > N THEN [EINIZE]
K1 = K + 1
PRINT
PRINT "VERTEX ";K1
INPUT "X = ";X1
INPUT "F = ";F1
IF X1 = X0 THEN [EISIZE]
REM ==COMPUTE COEFFICIENTS==
A0 = A0 + (X1 -X0) * (F1 + F0)
P = (F1 -F0) / (X1 -X0)
Q = F0 -P * X0
W = 0
FOR I = 1 TO M
W = W + W0
Z0 = W * X0
Z1 = W * X1
C0 = COS(Z0)
C1 =COS(Z1)
S0 = SIN(Z0)
S1 = SIN(Z1)
C2 = C1 -C0
C3 = X1 * C1 -X0 * C0
S2 = S1 -S0
S3 = X1 * S1 -X0 * 30
E0 = P / (W * W)
E1 = Q / W
A1=E0* (C2 +W* S3)+ E1 * S2
B1 = E0 * (S2 -W * C3) -E1 * C2
A(I) = A(I) + A1
B(I) = B(I) + B1
NEXT I
[EISIZE]
X0 = X1
F0 = F1
GOTO [FISIZE]
[EINIZE]
RETURN
REM ==OUTPUT RESULTS::
[NIZEZE]
PRINT
PRINT"'F0URIER COEFFICIENTS"
PRINT "********************"
PRINT
T2 = 2 / T
A0 = A0 / T
W = 0
PRINT ">N = 0   W=0"
PRINT
PRINT "A = ";A0
PRINT
FOR I = 1 TO M
W = W + W0
F = W / P2
A1 = A(I) * T2
B1 = B(I) * T2
IF ABS(A1) > 1/10^8 THEN [ONZEEIZE]
A1 = 0
[ONZEEIZE]
IF ABS(B1)> 1/10^8 THEN [ONONZEZE]
B1 = 0
[ONONZEZE]
PRINT "N = ";I;"W = ";W;
PRINT "W/TW0PI = ";F
PRINT "A = ";A1;
PRINT "   ";
PRINT "B = ";B1
PRINT
NEXT I
RETURN
[ONONEIZE]
END