OCXO module locks to GPS, for LTE & 4G base stations and 1E-12 stability

March 28, 2014 // By Graham Prophet
IQD’s IQCM-100 GPS OCXO module for use in LTE and 4G base stations achieves a holdover specification of 1.5 µsec over a period of 24 hours when locked to a 1pps (Pulse Per Second) input from an external GPS receiver, easily meeting 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 ±1x10 -12 when locked to a 1PPS GPS signal and can compete with the performance of many atomic clock references.

Housed in a 65 x 65 mm hermetically sealed through-hole package, the IQCM-100 has an HCMOS output, operating temperature range of –10 to 60C, 5V supply voltage and a current input of 2 mA 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.

A 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.

IQD Frequency Products; www.iqdfrequencyproducts.com