White Papers

We believe the Sonoma Time Server is the most secure time server available. This is partly due to a philosophy of simplicity. We use a streamlined operating system and no unnecessary protocols. All convenience protocols, like httpd, snmpd, telnetd and even sshd can be disabled. System settings are not modifiable via snmp or http. This paper lists steps that we recommend to further secure Sonoma.

Large earth stations host communication systems that provide mission-critical, high-bandwidth services to multiple customers. Within these earth stations are many frequency-based devices with independent local oscillators that generate and convert carrier frequencies, and modulate and demodulate data. Locking these oscillators to a common, stable and low-noise frequency reference distribution system is fundamental to minimizing frequency issues and supporting higher data rates.

The satellite communications infrastructure provides critical services for government and civil applications at increasing carrier frequencies and data rates. Within the ground and space-borne systems are devices that generate microwave level frequencies that form uplinks and downlinks. At the core of these systems are high-quality frequency references that are fundamental to establishing stable, high bandwidth communication links

Time is not just an extraneous network service.  Accurate time is essential to determining the order in which events occur and is a fundamental aspect of transaction integrity, logging/auditing, troubleshooting and forensics.  Accurate, reliable time is necessary for financial and legal transactions, transportation and distribution systems, database management and many other applications involving widely distributed resources.

The Precision Time Protocol, as defined in the IEEE-1588 standard, provides a method to precisely synchronize computers over a Local Area Network (LAN). PTP is capable of synchronizing multiple clocks to better than 100 nanoseconds on a network specifically designed for IEEE-1588.

This paper introduces a new class of precision timing and frequency reference that indirectly receives GPS timing and frequency via the transmissions from Code Division Multiple Access (CDMA) mobile telecommunications base stations.  EndRun Technologies has developed and is manufacturing a proprietary time and frequency engine specifically optimized to faithfully reproduce the inherent precision time and frequency characteristics of the IS-95 CDMA spread spectrum signals. The salient characteristics of the IS-95 CDMA signals which make it so well suited to this use and a general receiver architecture are described. Performance data versus similar references that use conventional GPS reception are also presented.  Presented at Precise Time and Time Interval Systems and Applications (PTTI) Meeting in November 2001.

This is a report written by the National Institute of Standards and Technology (NIST) about tests performed on our Meridian II Precision TimeBase.

EndRun NTP Servers are primarily designed for Stratum 1 operation, but also support Stratum 2. EndRun products can be configured for peering but we don’t recommend it for Stratum 1 Time Servers. This paper explains why. It also explains the difference between Stratum 2 mode and peering.

This document explains the methodology to measure and adjust the timing outputs from an EndRun product to the 10-nanosecond RMS level of agreement with UTC. 

This paper will show that the NTP and PTP timestamps from EndRun Technologies Network Time Servers are traceable through the National Institute of Standards and Technologies (NIST), and the United States Naval Observatory (USNO) to Coordinated Universal Time (UTC) maintained by the International Bureau of Weights and Measures (BIPM). 

A new way of obtaining precision, UTC traceable time and frequency has come of age, made possible by the rapidly expanding, global deployment of CDMA.  In essence, the CDMA base stations act as repeaters of the GPS timing information they receive from the satellites.  The spread-spectrum modulation scheme employed by the IS-95 CDMA system allows this GPS time reference to be extracted from the base station transmissions with a high degree of precision.  Presented at Precise Time and Time Interval Systems and Applications (PTTI) Meeting in November 2000.

Today, High Frequency Trading (HFT) requires low latency and knowledge of UTC time in capital markets where a difference of better than one millisecond provides a competitive advantage to trading firms.  Better than 10-microsecond accuracy to UTC can be achieved using Code Division Multiple Access (CDMA) and IEEE-1588 Precision Time Protocol (PTP) without routing an external antenna. Presented at the 42nd Annual Precise Time and Time Interval Systems and Applications (PTTI) in November 2010.