Agilent 33120A User's Guide

Chapter 7 TutorialModulationYou can use the equations on the next page to determine specificwaveform lengths and modulation frequencies when more precisecontrol is needed. Normally, you should not have to perform thesecalculations.The function generator incorporates an internal 8-bit (– 7 bits peak)digital-to-analog converter (DAC) to create an analog copy of themodulation signal for amplitude modulation (AM). This signal isinternally applied to a conventional four-quadrant analog multipliercircuit to achieve amplitude modulation. Similarly, the generator usesdigital signal processing to combine the carrier and modulation signalsfor frequency modulation (FM). The FM modulation signal maintains12-bit resolution for frequency values.The following equations and example describe the capabilities andlimitations of the 33120A’s internal modulation signal generator.Parameter Definitions:Maximum Point Clock (C) = 5 MSa/ s (for AM)1.25 MSa/ s (for FM)Modulation Prescaler (S) = integer numbers (truncated) from 1, 2, 3, ... 2 20Constant (k) = 4,900 (for AM)624 (for FM)Modulation Frequency (F) = 10 mHz to 20 kHz (for AM)10 mHz to 10 kHz (for FM)Points (P) = values from 2,000 to 4,000even numbers only (rounded down)294