Integration Manual

SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R11 Product testing Page 140 of 157
5.2.2 RF functional tests
The overall 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
AT+UTEST command over the AT command user interface.
The AT+UTEST 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-R4/N4 series AT Commands Manual [2] for the AT+UTEST 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 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 AT+UTEST 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 58 illustrates a typical test setup for such an RF functional test.