R&S SMB Procedures after Module Replacement
1407.0806.82 2.1 E-5
2 Procedures after Module Replacement
T
his chapter describes all necessary measures to restore the performance of the R&S SMB after
module replacement.
There are no manual adjustments to be performed. Internal and external adjustment routines are
implemented for this purpose.
Spare part RF boards are tested at Rohde & Schwarz with calibrated working standards according to the
performance test. All measurement values are within the specified values including the measurement
uncertainty as a minimum guard band. Power levels are corrected to nearly ideal values. When installing
a spare part RF board the only difference at the RF side is the connecting cable between the RF board
and the front panel. When testing the RF boards Rohde & Schwarz uses the same type of cable as it is
installed in the R&S SMB.
OCXOs are tested at Rohde & Schwarz for the frequency adjustment range and the control voltage for
an exact 10 MHz output frequency. This control voltage is coded in a digital value and stored on the
OCXO module. In the R&S SMB the digital value is read from the OCXO module.
The probability that the R&S SMB meets it specifications after the replacement of a RF board and / or
an OCXO is very high. To increase this probability even further and to detect a defective connecting
cable between the RF board and the front panel Rohde & Schwarz recommends to adjust and to verify
the power level and the reference frequency according to the instructions in the table below
If a calibration of the instrument is strictly necessary the performance test should be performed
completely.
After replacing an assembly, check the following table to see which service procedure you perform.
Changed module Required adjustment/correction Recommended Test Procedure (refer to
chapter 1 Performance Test "Checking the
rated characteristics")
Basis Board Setup/Internal Adjustments/Adjust All
set correct time and date, see below.
None
RF Board Setup/Internal Adjustments/Adjust All
External Level Correction (power sensor NRP-
Z91 or NRP-Z92 required)
Level Data at 0 dBm
OCXO Setup/Internal Adjustments/Adjust All Reference Frequency “Output of Internal
Reference”
Stereo Coder Setup/internal Adjustment/Adjust All
Setup/internal Adjustment/Adjust S/P DIF
(requires release of protection level 2)
MPX deviation and pilot tone deviation
Power Supply Setup/Internal Adjustments/Adjust All None
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