3 WLAN Mode
3.6 Modulation Analysis Measurement
Center Frequency
Sets the frequency that corresponds to the horizontal center of the graticule (when
frequency Scale Type is set to linear). While adjusting the Center Frequency the
Span is held constant, this means that both Start Frequency and Stop Frequency
will change.
Remote Command
[:SENSe]:FREQuency:CENTer <freq>
[:SENSe]:FREQuency:CENTer?
Example
:FREQ:CENT 50 MHz
:FREQ:CENT UP
changes the center frequency to 150 MHz if you use FREQ:CENT:STEP 100 MHz to set the center
frequency step size to 100 MHz
:FREQ:CENT?
Notes This command sets the RF, External Mixing or I/Q Center Frequency depending on the selected input
For RF input it is equivalent to FREQ:RF:CENT
For I/Q input it is equivalent to FREQ:IQ:CENT
For External Mixer it is equivalent to FREQ:EMIX:CENT
Preset and Max values are dependent on Hardware Options
If no terminator (e.g., MHz) is sent the terminator Hz is used. If a terminator with unit other than
Frequency is used, an invalid suffix error message is generated. Forceful -131
Dependencies Start, Stop, Center and Span have interdependencies. These must be strictly enforced when any of
these four values is modified.
The Center Frequency can be limited by Start or Stop Freq limits, if the Span is so large that Start or
Stop reaches their limit.
Couplings When operating in “swept span”, any value of the Center Frequency or Span that is within the
frequency range of the analyzer is allowed when the value is being set through the front panel numeric
keypad or the SCPI command. The other parameter is forced to a different value if needed, to keep the
Start and the Stop Frequencies within the analyzer’s frequency range
Coupling between center frequency and span: numeric (keypad) entries are treated differently than
changing the value using the step keys (up/down arrows) or the knob. Similarly, for remote operation
sending a numeric frequency value is treated differently than the UP|DOWN keywords
Numeric entries (keypad or remote) - any value of center frequency or span (within the frequency
range of the analyzer) is allowed. The other parameter is forced, as necessary, to keep the Start Freq
and Stop Freq within the analyzer frequency range
Knob or Step keys (up/down arrows) or UP|DOWN keywords - the value of the parameter being
changed (center frequency or span) is limited so the other parameter is not forced to a new value.
Thus, if only the step keys and knob are used, you can get back to the initial Center Freq and Span by
changing only the current parameter
NOTE: since out-of-range Start Freq and Stop Freq are never allowed, markers and trace math work
nicely without requiring anything special for out-of-range conditions
Preset Depends on instrument maximum frequency, mode, measurement, and selected input
WLAN Mode User's &Programmer's Reference 950
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