Should I use a TCXO or XTAL as Reference Clock?

The accuracy of your reference clock has a direct impact on the accuracy of your generated RF signal. A certain amount of frequency error on an RF signal can be tolerated in a system. However, errors become problematic when the radio transmits outside of its designated channel or when the Automatic Frequency Control (AFC) loop of the receiving device cannot handle the error. To understand if a certain reference can be used, users can calculate the maximum expected frequency error based on the spec of the reference used and check if it is compatible with the desired channel spacing of the system and AFC requirements of the radio. Systems with narrow channel spacing (12.5 kHz for example) or low data rates (<10kbps for example), are more sensitive to these types of error and typically use a TCXO as they are more accurate when compared to an XTAL. Another advantage of using a TCXO is faster startup time. The advantage of using an XTAL is that they’re typically lower cost when compared to a TCXO.