di2622l2.txt 
;**************************************************************************************************
; LISTING 2 - TABLE GENERATION FOR DUAL-TONE PWM OUTPUTS
;
; "Generate CID/CIDCW analog signals," EDN, Dec 7, 2000, pg 188

; http://www.ednmag.com/ednmag/reg/2000/12072000/designideas.htm#25di2
;
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PI = 3.1415926#
KM = 182              ' MAXIMUM RANGE OF PULSE WIDTH
DT = 576 / 11059200   ' TIME FOR EACH SAMPLE
DTI = DT
F1 = 19200 / 7        ' F1 = 2742.9 (2750)
F2 = 19200 / 9        ' F2 = 2133.3 (2130)
DTI = DT
FOR I = 1 TO 63       ' 63 SAMPLES THEN REPEAT
A = SIN(2 * PI * F1 * DT)  ' GENERATE F1 SINE WAVE
B = SIN(2 * PI * F2 * DT)  ' GENERATE F2 SINE WAVE
V = KM / 2 + (KM / 4) * A + (KM / 4) * B  'GENERATE F1 + F2 SINE WAVE
PRINT I, DT, V
DT = DT + DTI         ' NEXT SAMPLE
NEXT I