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A unique feature in CC1020, CC1021 and CC1070 is the very fine frequency resolution, which can be used for temperature compensation of the crystal if its temperature drift curve is known and a temperature sensor is included in the system. Even initial adjustment can be performed using the frequency programmability. This eliminates the need for an expensive TCXO and trimming in some applications. This application note describes how to perform crystal error compensation by reprogramming the PLL. The main focus is on temperature compensation, but compensation of initial crystal tolerance and crystal loading is also discussed. The discussion and measurements in this application note is based on the CC1020 transceiver.
http://www.ti.com/litv/pdf/swra065