APR is the guaranteed plus and minus frequency deviation of a VCXO from the nominal frequency when the control voltage is set to the maximum and minimum value. It is guaranteed over manufacturing tolerances, supply voltage, operating temperature and aging. APR is calculated by subtracting the Total Pull Range from the Total Stability of the VCXO. The Total Pull Range is the maximum variation in VCXO frequency over changes in control voltage under constant supply voltage and temperature. Total Stability is the variation in VCXO frequency when the control voltage is held at the nominal value over changes in manufacturing tolerances, supply voltage, operating temperature and aging. This difference results in the frequency variation that can be guaranteed due to the control voltage independent of all other conditions and variations. APR is derived from an output frequency range budget for a VCXO that accounts for all factors that contribute to the frequency deviation of the VCXO. See the example calculation below. Refer to application note AN-847 for more details. For other questions not addressed by the Knowledge Base, please submit a technical support request.