Agilent Technologies Signal Analyzer N9030a - Manual (Page 580)

6 RLC Swept SA Measurement Front-Panel & SCPI Reference
FREQ Channel
settings of Source Numerator, Source Denominator and Power Sweep.
Couplings In the Spectrum Analyzer, the four parameters Center Freq, Start Freq, Stop Freq and Span are
interdependent, as changing one necessarily affects one or more of the others. The couplings
between Center Freq and Span are detailed under the key descriptions for those keys. These
couplings also affect Start Freq and Stop Freq.
You cannot set Start frequency = Stop frequency. You cannot select zero span by setting Start =
Stop. The instrument will alter the value of the last setting to maintain a minimum value of 10 Hz
for the difference between Start and Stop.
Preset Start Freq does not preset. On Mode Preset, Span & CF preset, and Start Freq is derived. On a
Meas Preset only Span presets, CF does not, so Start Freq will vary depending on CF.
When a Mode Preset is performed while in External Mixing, the Start frequency of the current
Mode is set to the nominal Min Freq of the lowest harmonic range in the Harmonic Table for the
current mixer setup.
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 Start Freq will preset to a frequency below the
preset Center Freq by ½ of the maximum Span.
When Restore Input/Output Defaults is performed, the mixer presets to the 11970A, whose Start
frequency is 26.5 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 Start Freq is 26.5 GHz.
State Saved Saved in instrument state
Min –80 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 Start 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:STARt? MIN.
Max Depends on the instrument maximum frequency – 10 Hz. 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, it depends on the value of the other three interdependent
parameters.
While in External Mixing, the maximum Start 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:STARt? MAX.
580 Remote Language Compatibility Measurement Application Reference