Test 2-9: Total Harmonic Distortion (cont’d)
Example Program (cont’d)
600 !Measure harmonics 2-9
610 Sum_amp_sqr=0
620 FOR Harmonic=2 TO 9
630 GOSUB Meas_amp
640 Sum_amp_sqr=Sum_amp_sqr+10^(Result/10) !Sum of squared voltages
650 NEXT Harmonic
660 !
670 Thd=20*LGT(SQRT(Sum_amp_sqr)) !Calculate THD In dBc
680 SUBEXIT
690 !
700 Meas_fund: !
710 PRINT "FUNDAMENTAL"
720 PRINT "Set Spectrum Analyzer Center Freq to: "&VAL$(Frequency) &" Hz."
730 PRINT "Measure amplitude at the center frequency."
740 PRINT
750 INPUT "Enter amplitude (in dBm):",Baseline
760 RETURN
770 !
780 Meas_amp: !
790 PRINT "HARMONIC =";Harmonic
800 PRINT "Set Spectrum Analyzer Center Freq to: "&VAL$(Frequency* H ar mo nic)&" H z. "
810 PRINT "Measure amplitude at the center frequency."
820 PRINT
830 INPUT "Enter amplitude (in dBm):",Reading
840 Result=Reading-Baseline
850 RETURN
860 SUBEND
68 Verification Te sts Agilent E1445A Serv ice Manual