v1.0

RX functionality test

The %XRFTEST AT command with the RX ON parameters enables the RF receiver with the given parameters and returns the result of the antenna power measurement or Signal-to-Noise Ratio (SNR). The reported parameter is set by the <test> parameter following the %XRFTEST AT command. The RX OFF parameters disable the RF receiver.

The recommended signal level for RX testing is -90 dBm. The expected SNR with this signal level is normally more than 12 dB.

Note: The reported SNR is very sensitive to external RF disturbance that may be present in the test environment. An RF shielded chamber is recommended as a stable test environment. A known device, such as a golden unit, can be used as a reference to confirm the validity of the test result.

The value of the power measured at the antenna port is given in the q8 (dBm) format. Dividing the result by 28 = 256 gives the dBm value of the antenna power.

The following command example executes an RX signal level (RSSI) test:

%XRFTEST=0,1,1,21400,−65,0	// RX ON (B1,2140.0MHz,-65dBm,NB1 mode)
%XRFTEST: -17002			// Result: -17002/256 = -66.4dBm
OK

%XRFTEST=0,0			// RX OFF
OK

The measured SNR is given in the q4 (dB) format. Dividing the result by 24 = 16 gives the dB value of the antenna power. This measurement reports both the SNR and RSSI values.

The following command example executes an RX SNR test:

%XRFTEST=3,1,1,21400,-65,0	// RX ON (B1,2140.0MHz,-65dBm,NB1 mode)
%XRFTEST: 496,-17002		// Res: 496/16=31dB, -17002/256=-66.4dBm
OK

%XRFTEST=0,0			// RX OFF
OK

The input parameters of the RX functionality test are described in the following table:

Table 1. Input parameters of RX functionality test
Parameter name Parameter description Value Value description
<param0> 3GPP band number 1-66 Bands supported by nRF9160
<param1> Frequency 100 kHz raster 6000-22000 Corresponds to 600-2200 MHz
<param2> Signal level at antenna -127 to -25 Signal generator level at antenna [dBm]
<param3> System mode 0-1 NB1 = 0

M1 = 1

The signal level at antenna <param2> is used to set the receiver gain. It is recommended to set it to equal to the expected signal level at the antenna input.

For bands supported by nRF9160, see nRF9160 Product Specification.

For more information on RX testing with the %XRFTEST AT command, see RX testing in nRF91 AT Commands Reference Guide.