The IQCM-110 is a GPS disciplined OCXO incorporating GPS receiver with a 1PPS output. When coupled to an external aerial via the incorporated SMA connector, in the event of the loss of the GPS signal the highly specified 10 MHz OCXO will switch-in with a holdover capability of 1.5 µSeconds for a 24-hour period thereby maintaining lock until restoration of the reference signal. The design incorporates an internal adaptive algorithm which enables the module to ‘learn’ the parameters of the GPS signal after a period of 2 days of lock so that the holdover function can start in the event of signal failure. An internal alarm is built-in to indicate lock failure and subsequent restoration of signal. In addition, the unit incorporates a serial connection for more detailed interrogation of the device’s performance. It is Intended for a range of applications including land based telecommunications systems and marine based navigation systems.