
R&S FSH
Digital Modulation Analyzer
Measurements on LTE Signals
Operating Manual 1309.6275.12 - 14
211
M
Select the menu item that corresponds to the setup of the equipment you are
measuring.
If you want to measure a specific antenna, select the antenna number. Note that
selecting a specific antenna in multiple antenna systems is available only for 2-antenna
systems.
If you want to measure all antennas of the system, select the "Over-the-air" menu item.
7.5.4.7 Selecting the Unit of the Carrier Frequency Error
The absolute frequency error is the sum of the frequency error of the R&S FSH and
that of the device under test. If the frequency error is more than 1 kHz, the R&S FSH is
not able to synchronize with the signal. If possible, you should synchronize the receiver
and the transmitter.
The carrier frequency error can have the unit Hz or ppm.
M
Press the MEAS key.
M
Press the "Display Settings" softkey.
M
Select the "Hz" or "ppm" menu item.
The R&S FSH shows the carrier frequency error in the unit you have selected.
7.5.4.8 Configuring EVM Results
In case of the EVM, you can define the unit of the EVM and EVM calculation method.
To obtain EVM values according to standard, the channel estimation and EVM
windowing methods defined in 3GPP TS 36.141 are used. Prerequisites for a standard
compliant measurement are signals according to the enhanced test models defined in
36.141 and an external frequency reference delivered via the Ref In connector or via
GPS. The EVM according to standard measurement is mainly useful for high accuracy
signal quality measurements with cable-connected eNodeB antenna ports. The
measurement takes longer but the EVM value incorporates more signal errors like
inter-symbol-interference.
If the EVM is not measured with the “EVM According to Standard” option enabled,
optimum channel estimation and EVM calculation methods are used. Especially for
over-the-air measurements this setting is useful since influences of the air interface like
inter-symbol-interference are compensated. Additionally this mode is faster.
Selecting the unit of the EVM
M
Press the MEAS key.
M
Press the "Display Settings" softkey.
M
Select either the "%" or "dB" menu item.
The R&S FSH shows the EVM in the unit you have selected.