Keysight x-series User Manual

3 Spectrum Analyzer Mode
3.2 Swept SA Measurement
directly set Center Frequency for a specific input (see "RF Center Frequency" on
page 285 and "Ext Mix Center Freq" on page 286).
Center Frequency is remembered as you go from input to input. Thus, you can set a
Center Frequency of 10GHz with the RF Input selected, change to BBIQ and set a
Center Frequency of 20MHz, then switch to External Mixing and set a Center
Frequency of 60GHz. When you return to the RF Input, Center Frequency reverts to
10GHz; back to BBIQ and it is 20MHz; back to External Mixing and it is 60GHz.
Remote Command
[:SENSe]:FREQuency:CENTer <freq>
[:SENSe]:FREQuency:CENTer?
Example Set Center Frequency to 50MHz:
:FREQ:CENT 50 MHz
Increment Center Frequency by the value of "CF Step" on page 300:
:FREQ:CENT UP
Return the current value of Center Frequency:
:FREQ:CENT?
Notes 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 depend on Hardware Options
If no terminator (for example, 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
Dependencies Center Frequency can be limited by Start Freq or Stop Freq limits, if Span is so large that start or stop
reach their limits
Couplings When operating in “swept span”, any value of Center Frequency or Span that is within the frequency
range of the instrument is allowed, if the value is being set through the front panel numeric key pad or
the SCPI command. The other parameter is forced to a different value if needed, to keep Start and
Stop Frequencies within the instrument’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 instrument) is allowed. The other parameter is changed, as necessary, to keep the
Start Freq and Stop Freq within the instrument 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 return to the initial Center Frequency
and Span by changing only the current parameter
Note that, since out-of-range Start Freq and Stop Freq are never allowed, markers and trace math
282 Spectrum Analyzer Mode User's &Programmer's Reference

Keysight x-series Specifications

General

Analysis Bandwidth	Up to 1 GHz (depending on model)
Real-Time Bandwidth	Up to 1 GHz (depending on model)
Form Factor	Benchtop
Connectivity	LAN, USB, GPIB
Resolution Bandwidth	1 Hz to 10 MHz (depending on model)