Set command

The set command measures Signal-to-Noise Ratio (SNR).

To measure SNR correctly, the Carrier Wave (CW) offset must be +330 kHz for the LTE-M and DECT NR+ modes and +45 kHz for the Narrowband Internet of Things (NB-IoT) mode.



The set command parameters and their defined values are the following:

3 – RX SNR.
1 – ON.
Note: OFF <operation> is not needed due to automatic stop.
3GPP band number. Use 24 for Global Navigation Satellite System (GNSS) reception.
DECT NR+ bands 1, 2, 9, and 22 are supported when <param3> is 10. See ETSI TS 103 636-2 V1.4.1 Table 5.2-1.
Valid range 6000–22000 (corresponds to 600.0 MHz–2200.0 MHz).
In DECT NR+, the valid range is 18800–19300 (corresponds to 1880.0 MHz–1930.0 MHz) depending on the DECT NR+ band selected in <param0>.
RX signal power at the SiP antenna port.
Valid range from −127 dBm to −25 dBm.
System mode.
0 – NB-IoT.
1 – LTE-M.
10 – DECT NR+.
Enabling AFC correction during SNR test.

1 – Enable.

0 – Disable.

If <param4> is not given, AFC correction is disabled.

Response syntax:

%XRFTEST: <snr>,<antenna_power>,<sb2hnbr>,<headroom>

The response parameters and their defined values are the following:

Result of the SNR measurement in q4 dB. q4 means that dividing the result by 24 = 16 dB.
The SNR calculation is done by computing the power of the signal bins and dividing it by the power of all the other bins.
Measured signal power at the System in Package (SiP) antenna port in q8 dBm. q8 means dividing the result by 28 = 256 gives dBm.
Signal bin to highest noise bin ratio in q4 dB.
Computed by dividing the signal bin by the power of the highest noise bin.
Allows to find spurious signals possibly affecting reception. The expected value is the same or higher than <snr>.
Time domain signal headroom in dBFullScale.
Expected value is −15 dBFS or −16 dBFS if the signal level in generator corresponds to the level given in <param2>.

The following command example enables the RX SNR measurement and RF receiver for Band 1, 2140.0 MHz, −65 dBm, LTE-M mode, AFC correction enabled:

%XRFTEST: 496,-17002,598,-16
Note: 496/16 = 31 dB. −17002/256 = −66.4 dBm. 598/16=37.3 dB.