SWRA682 December 2020 CC1310 , CC1312PSIP , CC1312R , CC1314R10 , CC1350 , CC1352P , CC1352P7 , CC1352R , CC1354P10 , CC1354R10
Most PHYs uses the default IF frequency. The default frequency is dependent on the RX BW and is given in the Receiver Bandwidth Settings table in the device-specific Technical Reference Manual (TRM). In some cases it could be a benefit to use a different IF than the default. The IF frequency is set through CMD_PROP_RADIO_DIV_SETUP.intFreq . A lower IF can potentially improve blocking as a lower anti-aliasing BW can be used.
The .intFreq can be calculated as dec2hex(IF frequency*4096/1e6).
Good design practice: RXIF - deviation + guard band > DC. Guard band is needed to keep the "lower end" of the RX BW sufficiently above DC. There is a DC filter that removes 1/f noise, and the guard band is needed so that the DC filter does not remove any of the signal.