Integration Manual

Table Of Contents
SARA-R5 series - System integration manual
UBX-19041356 - R03 Product testing Page 104 of 123
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5.2.2 Cellular RF functional tests
The overall cellular RF functional test of the device including the antenna can be performed with basic
instruments such as a spectrum analyzer (or an RF power meter) and a signal generator with the
assistance of the +UTEST AT command over the AT command user interface.
The +UTEST AT command provides a simple interface to set the module to Rx or Tx test modes
ignoring the LTE signaling protocol. The command can set the module into:
transmitting mode in a specified channel and power level in all supported bands
receiving mode in a specified channel to return the measured power level in all supported bands
See the SARA-R5 series AT commands manual [2] for the +UTEST AT command syntax
description and detail guide of usage.
This feature allows the measurement of the transmitter and receiver power levels to check the
component assembly related to the module cellular antenna interface and to check other device
interfaces on which the RF performance depends.
To avoid module damage during a transmitter test, a suitable antenna according to module
specifications or a 50 termination must be connected to the ANT port.
To avoid module damage during a receiver test, the maximum power level received at the ANT port
must meet module specifications.
The +UTEST AT command sets the module to emit RF power ignoring LTE signaling protocol. This
emission can generate interference that can be prohibited by law in some countries. The use of
this feature is intended for testing purposes in controlled environments by qualified users and
must not be used during the normal module operation. Follow the instructions suggested in the
u-blox documentation. u-blox assumes no responsibilities for the inappropriate use of this feature.
Figure 71 illustrates a typical test setup for such an RF functional test.
Application board
SARA-R5 series
ANT
Application
Processor
AT
commands
Cellular
antenna
Spectrum
analyzer
or
power
meter
IN
Wideband
antenna
TX
Application board
SARA-R5 series
Application
Processor
AT
commands
Signal
generator
OUT
Wideband
antenna
RX
ANT
Cellular
antenna
Figure 71: Setup with spectrum analyzer or power meter and signal generator for SARA-R5 series RF measurements