9000 REM ***** LPFLTR ***** ENGINEERING PROGRAM ****: 9001 REM ***** VERSION 1 ***** 7/31/69 ***** 9002 REM DESIGNS LOW PASS FILTER 9003 PRINT "PROGRAM FOR THE DESIGN OF A LOW PASS FILTER" 9004 PRINT 9005 PRINT "WHAT IS THE DESIRED CHARACTERISTIC IMPEDANCE IN OHMS"; 9006 INPUT R 9007 MAT F=ZER 9008 PRINT 9009 PRINT "WHAT IS THE DESIRED CUTOFF FREQUENCY IN HZ"; 9010 INPUT F(1) 9011 PRINT 9012 PRINT"HOW MANY ATTENUATORS ARE DESIRED IN THE STOP BAND"; 9013 INPUT A 9014 GOTO 9026 9015 FOR I=2 TO A+1 9016 PRINT "WHAT IS THE FREQUENCY FOR ATTENUATOR NUMBER"I-1; 9017 INPUT F(I) 9018 PRINT 9019 NEXT I 9020 LET L=1000*R/(3.14159*F(1)) 9021 LET C=1.E+06/(3.14159*F(1)*R) 9022 L(1)=.6*L/2 9023 S(1)=.64*L/1.2 9024 C(1)=.6*C/2 9025 GOTO 9029 9026 PRINT 9027 IF A=0 THEN 9020 9028 GOTO 9015 9029 FOR I=2 TO 10 9030 IF F(I)=0 THEN 9036 9031 M(I)=SQR(1-F(1)/F(I)*F(1)/F(I)) 9032 L(I)=M(I)*L/2 9033 S(I)=L*((1-M(I)*M(I))/(4*M(I))) 9034 C(I)=C*M(I) 9035 NEXT I 9036 PRINT 9037 PRINT 9038 GOSUB 9077 9039 GOSUB 9071 9040 GOSUB 9075 9041 GOSUB 9071 9042 PRINT ">",L/2+L(1),"MH"," I" 9043 GOSUB 9071 9044 PRINT"+---------------";C;" MFD ---------------------+" 9045 GOSUB9071 9046 LET I=2 9047 IF F(I)=0 THEN 9065 9048 PRINT ">",L/2+L(I),"MH"," I" 9049 GOSUB 9071 9050 PRINT"+--------";S(1)" MH +";C(2);" MFD -----------+" 9051 GOSUB9071 9052 FOR I=3 TO 10 9053 IF F(I)=0 THEN 9059 9054 PRINT ">",L(I)+L(I-1),"MH"," I" 9055 GOSUB 9071 9056 GOSUB9071 9057 GOSUB 9071 9058 NEXT I 9059 PRINT ">",L(I-1)+L(1),"MH"," I" 9060 GOSUB 9071 9061 GOSUB 9075 9062 GOSUB 9071 9063 GOSUB 9077 9064 GOTO 9079 9065 PRINT ">",L/2+L(1),"MH"," I" 9066 GOSUB 9071 9067 GOSUB 9075 9068 GOSUB 9071 9069 GOSUB 9077 9070 GOTO 9079 9071 FOR N=1 TO 2 9072 PRINT"I";SPACE$(53%);"I" 9073 NEXT N 9074 RETURN 9075 PRINT"+--------";S(1)"MH +";C(1);" MFD ------------+" 9076 RETURN 9077 PRINT"0<-------------------";R;" OHM LINE ------------------>0" 9078 RETURN 9079 PRINT 9080 PRINT 9081 PRINT "TERMINATING SECT'S GIVE MAX. ATTEN. AT"1.25*F(1)"HZ" 9082 IF F(2)=0 THEN 9088 9083 PRINT "IN ADDITION TO THOSE SPECIFIED AT:" 9084 FOR I=2 TO 10 9085 IF F(I)=0 THEN 9088 9086 PRINT F(I)"HZ" 9087 NEXT I 9088 GOTO9999 9999 END