New from IQD, the IQCM-100 GPS advanced OCXO module has been designed for use in LTE and 4G base stations and is able to achieve a holdover specification of 1.5 microseconds over a period of 24 hours when locked to a 1PPS (Pulse Per Second) input from an external GPS receiver, and so meets industry standard holdover requirements.
Incorporating an adaptive algorithm which has the ability to ‘learn’ from a stable GPS signal over a period of 2 days, the algorithm can be adjusted to allow for errors. Frequency is accurate to within ±1E-12 when locked to a 1PPS GPS signal and can compete with the performance of many atomic clock references.
Housed in a 65 x 65mm hermetically sealed thru-hole package, the IQCM-100 offers an HCMOS output, operating temperature range of –10 to 60 degrees C, 5V supply voltage and a current input of 2mA during warm up.
The module incorporates a low drop out voltage regulator coupled to a highly stable internal OCXO which is conditioned by a digital-to-analogue converter which in turn is fed from an ARM microcontroller. This controls an FPGA which provides the 1PPS output and is fed from the accurate GPS signal.
An interesting feature of this product is the availability to the user of some 21 internal algorithm parameters. Using a serial data word output, the user can access information including current status (warm up, holdover or lock); time since attaining lock status; current phase shift between signal input & output; average phase shift over the last hour.