3 WLAN Mode
3.9 Spectral Flatness Measurement
:FREQ:EMIX:CENT?
Notes This command is the same in all modes, but the parameter is Measurement Global. So the value is
independent in each mode and common across all the measurements in the mode.
Couplings When returning to External Mixing after having been switched to one of the other inputs (e.g., RF), you
will come back into the settings that you had when you left External Mixing. So you will come back to
the band you were in with the Center Frequency that you had. However, Span is not an input-
dependent parameter, therefore you will bring the span over from the other input. Therefore, the
analyzer comes back with the span from the previous input, limited as necessary by the current mixer
setup.
Preset 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. Similarly, the Stop frequency of the current Mode is set to the nominal Max Freq of the highest
harmonic range in the Harmonic Table. The Center Freq thus presets to the point arithmetically
equidistant from these two frequencies.
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 still sets the Center Freq to the midpoint of the Start and Stop Freq values in the Harmonic Table.
When Restore Input/Output Defaults is performed, the mixer presets to the 11970A, whose Start and
Stop frequencies are 26.5 and 40 GHz respectively. The center of these two frequencies is 33.25 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 Center Freq is 33.25 GHz.
State Saved Yes
Min The minimum frequency in the currently selected mixer band + 5 Hz
Max The maximum frequency in the currently selected mixer band - 5 Hz
If the knob or step keys are being used, also depends on the value of the other three interdependent
parameters Span, Start Frequency and Stop Frequency
I/Q Center Freq
SCPI command for specifying the I/Q Center Frequency. This command will set the
Center Frequency to be used when the I/Q input is selected, even if the I/Q input is
not the input which is selected at the time the command is sent. Note that the
Center Freq function in the Frequency menu on the front panel always applies to the
currently selected input.
Remote
Command
[:SENSe]:FREQuency:IQ:CENTer <freq>
[:SENSe]:FREQuency:IQ:CENTer?
Example
:FREQ:IQ:CENT 30 MHz
Notes This command is the same in all modes, but the parameter is Measurement Global. So the value is
independent in each mode and common across all the measurements in the mode.
1475 WLAN Mode User's &Programmer's Reference
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