R&S
FS-K30
Measurements & Settings
Measurement
modes & schematics
Software Manual 1300.6637.42 - 03
46
The Image Frequency displayed in the schematic indicates the range of the image
frequency for the current measurement set-up. This allows the user to determine
whether image frequency filters are required and for which frequency range the image
rejection of the DUT needs to be entered in the
Image Rejection
setting (of the
Frequency Settings view).
The two Fixed IF calculations should be used for frequency-converting DUTs that have
a fixed intermediate frequency (IF), for example, mixers. These options produce a
frequency list with a constant IF frequency for each measurement step but with a LO
frequency which varies from step to step according to the calculation selected. The
application will control an external signal generator (via the IEC bus) to generate the
LO signal. It is also possible to drive a voltage source that controls a VCO which
generates the LO signal.
The two Fixed LO calculations should be used for frequency-converting DUTs that
have a fixed Local Oscillator (LO) frequency, for example, satellite converters with a
fixed LO frequency. These options produce a frequency list with a constant LO
frequency for each measurement step but with an IF frequency which varies from step
to step according to the calculation selected.
2.1.3 Calibration
Calibration of the R&S FS-K30 application measures the noise introduced to a signal
by the spectrum analyzer itself.
This can then be compensated for in measurements on a Device Under Test. This
compensation is called 2nd Stage Correction, because the spectrum analyzer is the
second stage of the test set-up, the DUT being the first stage.
The 2nd Stage Correction setting can be found in the Measurement Settings view by
pressing the
SET MEAS
softkey.
The calibration status of the R&S FS-K30 application is shown on the right-hand-side
of the Title Bar at the top of the screen. Note that this status is the status of R&S FS-
K30 only and does not indicate if the spectrum analyzer itself is calibrated. If the
spectrum analyzer is uncalibrated, then a red “UNCAL” label will appear to the left of
any measurement results graph.
When any change is made to the Frequencies List, that is, the list of Receive
Frequencies (
RF
) at which measurements will be made, R&S FS-K30 will need to be
calibrated again. This is necessary to ensure that there is calibration data available for
every measurement step for the current measurement mode. The Frequencies List can
be found in the Frequency Settings view by pressing the
SET FREQ
softkey.
The procedure for performing a calibration of R&S FS-K30 is as follows:
1. Connect the noise source to the RF input of the spectrum analyzer. (see Fig. 24)
2. Provide the voltage supply for the noise source by connecting it to the +28V socket
of the analyzer (labelled NOISE SOURCE at the rear of the instrument) via a coax
cable and the low-pass filter. The low-pass filter is connected between the noise
source itself and the NOISE SOURCE socket of the analyzer as shown.
