An FCXO can be synchronized to several different input frequencies and produce different output frequencies. The FCXO output frequency can be a multiple of the input frequency. Corresponding FCXO modules are available for frequency ranges up to 100 MHz and above. The accuracy of the output frequency is comparable to that of crystal oscillators and is in the range of `10^-6`.
Frequency-controlled crystal oscillators are used for time synchronization in networks.