Guralp Systems Limited
MAN-RTM-0003 - Real-time Clock Operator's Guide

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1. Preliminary Notes 2. Introduction 3. Operation 4. Connector pin-outs 5. Specifications 6. Revision history

Chapter 2. Introduction

The CMG-RTM is a battery backed, high-precision, thermally-compensated, real-time clock module with simulated GPS output. It obtains its initial synchronisation from a GPS receiver and, once locked, starts generating NMEA sentences and a PPS (pulse per second) signal, making it suitable for use as a time-source for GPS-synchronised equipment in situations where GPS receivers are impractical. A large liquid crystal display provides status information.

Once the initial synchronisation source is removed, the CMG-RTM continues to run under battery power, maintaining timing through the use of a high-precision, thermally-compensated, crystal-controlled oscillator. The CMG-RTM can then be transported to the deployment site and connected to a digitiser, from which it subsequently draws power. Once powered, it will generate the NMEA and PPS signals which are required to synchronise the connected digitiser.

Each unit is individually factory-trained to calculate a temperature compensation table with 0.1°C granularity, ensuring stability of operation in a wide range of environments.

PreviousNext

1. Preliminary Notes 2. Introduction 3. Operation 4. Connector pin-outs 5. Specifications 6. Revision history