GPS advanced OCXO for LTE & 4G base stations

27th March 2014

Nat Bowers

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Datasheet

Specifically designed for LTE & 4G base stations, the IQCM-100 GPS advanced OCXO (Oven Controlled Crystal Oscillator) module has been introduced by IQD Frequency Products. It achieves a holdover specification of 1.5ms over a 24 hour period 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 ±1E-12 when locked to a 1PPS GPS signal and can compete with the performance of many atomic clock references.

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. The IQCM-100 operates over a temperature range from -10 to +60°C.

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.

Housed in a 65x65mm hermetically sealed thru-hole package, the IQCM-100 offers an HCMOS output, 5V supply voltage and a current input of 2mA during warm up.