916
Common Measurement Functions
FREQ Channel
Preset: On Mode Preset, Span & CF preset, and Stop Freq is derived. See “Center
Frequency Presets” on page 907 for a table which shows the Stop Freq after
Preset for various model and option numbers).
On a Meas Preset only Span presets, CF does not, so Stop Freq will vary
depending on CF.
When a Mode Preset is performed while in External Mixing, the Stop
frequency of the current Mode is set to the nominal Max Freq of the highest
harmonic range in the Harmonic Table for the current mixer setup.
NOTE If the current measurement has a limited Span
available to it, and cannot achieve the Span shown in
the table (Span=Stop Freq – Start Freq), the analyzer
uses the maximum Span the measurement allows, and
sets the Center Freq to the midpoint of the Start and
Stop Freq values in the Harmonic Table. Thus, in this
case, the Stop Freq will preset to a frequency above
the preset Center Freq by ½ of the maximum Span.
When Restore Input/Output Defaults is performed, the mixer presets to the
11970A, whose Stop frequency is 40 GHz.
Therefore, after a Restore Input/Output Defaults, if you go into External
Mixing and do a Mode Preset while in the Spectrum Analyzer Mode, the
resulting Stop Freq is 40 GHz.
State Saved: Saved in instrument state
Min: –79.999999999 MHz, unless Source Mode is set to Tracking, in which case it
is limited by the minimum frequency of the Source
If the knob or step keys are being used, depends on the value of the other three
interdependent parameters
While in External Mixing, the minimum Stop Freq you can set is determined
by the external mixing parameters. It will be close to the minimum LO
frequency (3.8 GHz if undoubled, 8.6 GHz if doubled) times the harmonic
number, for the lowest harmonic range in the Harmonic Table for the current
mixer setup. It can be queried with the SCPI command :FREQ:STOP? MIN.
Max: Depends on instrument maximum frequency. Note that, if the Source Mode is
set to Tracking, the effective instrument maximum frequency may be limited
by the source maximum frequency.
If the knob or step keys are being used, depends on the value of the other three
interdependent parameters.
While in External Mixing, the maximum Stop Freq you can set is determined
by the external mixing parameters. It will be close to the maximum LO
frequency (7 GHz if undoubled, 14 GHz if doubled) times the harmonic
number, for the highest harmonic range in the Harmonic Table for the current
mixer setup. It can be queried with the SCPI command :FREQ:STOP? MAX.
Default Unit: Hz