Rohde & Schwarz SMC100A - Page 249

R&S SMC100A Command Description
1411.4060.32 6.47 E-1
[SOURce:]FREQuency:OFFSet -50 GHz ... + 50 GHz
The command sets the frequency offset of a downconversion instrument, e.g. a mixer. If a frequency
offset is entered, the frequency entered with SOURce:FREQuency:... no longer corresponds to
the RF output frequency. The following correlation applies:
SOURce:FREQuency:... = RF output frequency + SOURce:FREQuency:Offset.
Entering an offset does not change the RF output frequency, but rather the query value of
SOURce:FREQuency:.....
Example:
SOUR:FREQ:OFFS 500kHz
'sets the frequency offset to 500 kHz.
*RST value Resolution Options SCPI
0 Hz 0.01 Hz Compliant
[SOURce:]FREQuency:SPAN 0...RF
m
ax
(RF
m
ax
depending on model)
This command specifies the span for the sweep. This setting in combination with the center
frequency setting ([SOUR]:FREQ:CENT) defines the sweep range.
This command is linked to the commands [SOUR]:FREQ:STAR and [:SOUR]:FREQ:STOP, i.e.
changing these values causes the SPAN value to change, and vice versa:
SPAN = (STOP - STARt)
Negative values for SPAN are permitted; STARt > STOP then applies.
Example:
FREQ:CENT 400 MHz
'sets the center frequency of the frequency sweep to 400 MHz.
FREQ:SPAN 200 MHz
'sets a span of 200 MHz. This sets the sweep range to 300 MHz to 500 MHz.
*RST value Resolution Options Correlation SCPI
400 MHz 0.01 Hz SPAN = (STOP - STARt) Compliant
[SOURce:]FREQuency:STARt 300 kHz...RF
max
(RF
max
depending on model)
This command sets the start frequency for the sweep mode. STARt can be greater than STOP.
This command is linked to the commands [SOUR]:FREQ:CENT and [SOUR]:FREQ:SPAN, i.e.
changing these values causes the STARt value to change, and vice versa:
STARt = (CENTer - SPAN/2).
As with the Frequency value entered in the header, the Offset value is also taken into
consideration with this command. The specified value range is therefore only effective if Offset is
set to 0. The value range for other Offset values can be calculated using the following formula:
300 kHz + Offset ... RF
max
+ Offset
Example:
FREQ:STARt 1 MHz
'sets the start frequency for the frequency sweep to 1 MHz.
FREQ:STOP 2 GHz
'sets the stop frequency for the frequency sweep to 2 GHz.
*RST value Resolution Options Correlation SCPI
100 MHz 0.01 Hz STARt = (CENTer - SPAN/2) Compliant