User`s manual

Standard Waveform Program Comments
The following comments give additional details on the program examples in
this chapter.
Sinusoid Function
Requirements
The sinusoid requires that the sample source (see “Sample Sources” below) is
set to
INTernal[1] (that is, TRIGger:STARt:SOURce INTernal[1]). This selects
the DDS frequency generator. No other sample source can generate a sinewave.
Reference
Oscillator Sources
• The SINusoid, SQUare, TRIangle, and RAMP functions can use any
of the reference oscillator sources. The sources selected by
[SOURce:]ROSCillator:SOURce are:
INTernal[1] – 42.94967296 MHz (power-on value)
INTernal2 – 40 MHz
CLK10 – 10 MHz (the VXIbus CLK line)
EXTernal – User provided value (the front panel “Ref/Smpl In” BNC)
ECLTrg0 or 1 – User provided value (the VXIbus ECL trigger lines)
• If using either the EXTernal or ECLTrg0 or 1 reference oscillator
sources, enter the source frequency to the AFG using
[SOURce:]ROSCillator:FREQuency:EXTernal < frequency>.
• For best frequency linearity, use the 42.9 MHz (that is, INTernal[1])
reference oscillator source with the DDS (frequency1) frequency
generator. This combination provides .01 Hz resolution. For higher
frequency values, use the 40 MHz (that is,
INTernal2) reference
oscillator source with the Divide-by-N (frequency2) frequency
generator. Use the other sources for custom frequency values.
However, any reference oscillator sources can be used with any
frequency generator.
Sample Sources
• The SINUsoid function only operates with the INTernal[1] sample
source.
• The SQUare, TRIangle, and RAMP functions operate with any of the
sample sources selected by the
TRIGger:STARt:SOURce command.
The functions can use either the DDS (frequency1) frequency
generator or the Divide-by-N (frequency2) frequency generator for
waveform generation. However, the DDS frequency generator gives
better frequency resolution and should be used for the these
functions. The Divide-by-N frequency generator should be used for
arbitrary waveform generation where high frequency values are
needed. The different sample sources are:
INTernal[1] (power-on value; selects the DDS frequency generator)
INTernal2 (selects the Divide-by-N frequency generator)
BUS (the GPIB GET or *TRG commands)
EXTernal (the front panel “Ref/Smpl In” BNC)
78 Generating Standard Waveforms Chapter 2