User`s manual

Note Direct frequency control (that is, the [SOURce:]FREQuency commands) is
only available with the INTernal1 and INTernal2 time base sources. For all
other sources, the output frequency depends upon the frequency of the time
base source.
[SOURce:]FREQuency commands will be accepted with other
time base sources, but become effective when the source is changed to
INTernal1 or INTernal2.
Divide-by-N Frequency
Synthesis
Fixed frequency (continuous) waveforms are the only signals allowed by the
Divide-by-N frequency synthesis method (
[SOURce:]FREQuency2
subsystem). All waveforms except standard function sine waves can be
output using Divide-by-N frequency synthesis.
AFG Frequency
Modes
There are four frequency “modes” available using the DDS time base
(
[SOURce:]FREQuency[1]). The modes selected by the
[SOURce:]FREQuency[1]:MODE command are:
• CW | FIXed – single frequency mode.
• FSKey – frequency shift keying mode
• LIST – frequency list mode
• SWEep – frequency sweep mode
CW or FIXed is the default mode but is specified in many of the programs
to emphasize that the arm source specified by
ARM[:STARt]:LAYer2:SOURce <source> is for fixed (continuous)
frequency waveforms.
Frequency Sweeping
and Lists
Frequency sweeping and frequency lists are only available using the DDS
time base. When setting the frequency mode,
SWEep must be selected for
frequency sweeps and
LIST must be selected for frequency lists.
198 Arming and Triggering Chapter 5