AFC measurement and set %XRFTEST

The Nordic-proprietary %XRFTEST command can be used to measure or set the AFC error value for a given frequency.v1.2.xv1.3.xpti_v1.1.x≥1

The %XRFTEST command allows starting RF to a desired frequency to test, debug, and verify configurations that depend on RF frequency, such as %XMAGPIO and %XMIPIRFFECTRL.

Some frequency error can occur because the signal generator’s and nRF9160’s reference clocks are different. This test allows to measure or set the frequency error and use the result value as compensation in subsequent tests. This improves the correctness of Signal-to-Noise Ratio (SNR) tests and transmission frequency, but has no significant effect on the power measurement results in the RX or TX tests. The relative Q30 formatted response value is stored to Non-volatile Memory (NVM) and can be used in RX and Global Positioning System (GPS) SNR tests if the AFC correction enabling parameter, for example <param4> in the RX SNR test, is 1.

The measurement expects the Carrier Wave (CW) in the signal generator to be 120 kHz lower than the given frequency. For example, if DUT frequency is 830 MHz, the signal generator must be set to 829.880 MHz.