nRF9160 is fully calibrated and does not require any additional RF calibration. It is enough to verify successful assembly and soldering. For this purpose, nRF9160 supports the Nordic-proprietary %XRFTEST RF test AT command. Testing with three of the main test modes for RF performance, RX, TX, and Global Positioning System (GPS) Signal-to-Noise Ratio (SNR), is supported.
To confirm the LTE RF functionality, usually testing either TX or RX is enough. For more information, see RX functionality test and TX functionality test.
The support for the AT command-based test mode is intended for non-signaling RF testing and allows the use of lower cost test equipment, such as a spectrum analyzer and RF signal generator. The following figures show alternative setups for RF testing.
In the setups in Non-signaling RF test setup for LTE and GPS RX mode testing, Non-signaling RF test setup supporting both TX and RX testing, and Non-signaling RF test setup using RF tester, the RF attenuator is intended to stabilize RF impedance seen by the nRF9160 antenna port due to test fixture and cabling. For example, an attenuator of 6-10 dB can be used.
The setup in the following figure supports only RX mode testing.
The setup in the following figure contains capability for both LTE TX and RX testing.
The setup in the following figure uses a non-signaling LTE tester for more advanced measurements.
The need for an RF switch or separate RF generator for GPS depends on the selected tester and the amount of parallel test setups.
The recommended voltage for the power supply is a minimum of 3.3 V for RF 3GPP compliancy. It is recommended to use a common timebase reference clock for all RF equipment if several sets of RF test equipment are used in the test setup.
For information on RF performance related test modes and other supported test capabilities, see nRF91 AT Commands Reference Guide.