RX SNR testing

To measure Signal-to-Noise Ratio (SNR) correctly, the Carrier Wave (CW) offset must be +330 kHz for the M1 mode and +45 kHz for NB1.

The parameters and their values are the following:

<test>
3 – RX SNR
<operation>
1 – ON
Note: "OFF" is not needed due to automatic stop.
<param0>
3GPP band number. Use 24 for Global Positioning System (GPS) reception.
<param1>
Frequency 100 kHz (,i.e. 2140 MHz is expressed as 21400).
<param2>
RX signal power at the System in Package (SiP) antenna port in dBm.

Valid range from −127 to −25.

<param3>
System mode.

Valid range 0–1. NB1 (0) or M1 (1).

<param4>v1.2.xpti_v1.1.x≥1
Enabling AFC correction during SNR test.

1 – Enable

0 – Disable

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

Response syntax when <operation> is ON:

%XRFTEST: <snr>,<antenna_power>

The response parameters and their values are the following:

<snr>
Result of the Serial Number (SNR) measurement in q4 dB. q4 means that dividing the result by 24 = 16 dB.
<antenna_power>
Measured signal power at the SiP antenna port in q8 dBm. q8 means divided dividing the result by 28 = 256 gives dBm.

The following command example enables the RX SNR measurement and RF receiver for Band 1, 2140.0 MHz, −65 dBm, M1 mode, AFC correction enabled:

%XRFTEST=3,1,1,21400,-65,1,1
%XRFTEST: 496,-17002
OK
Note: 496/16 = 31 dB and −17002/256 = −66.4 dBm.