Datum, the leading worldwide manufacturer of precision time and frequency products, supplies the timing components that are the heart of modern fiber-optic telecommunications. April Terreri clocks in with the story.

The average man on Main Street might think that his telephone conversations travel directly from his mouth to the ear of the person he’s talking to. Well, the reality is that our conversations travel not in a single stream of signals, but are broken up into fragments, or data packets. Ensuring that these packets are re-assembled properly to reach the listener’s ear is a matter of timing. “The main use of Datum time and frequency products is to provide this very precise timing in telecommunications networks,” says Robert Buckley, marketing communications manager for the Datum-Irvine division.

Founded in 1969 and headquartered in Irvine, Calif., Datum manufactures and markets a wide variety of high-performance time and frequency products used to synchronize the flow of information in today’s telecommunications networks. The company is a leading supplier of precise timing solutions for computing networks, satellite systems, electronic commerce and test and measurement applications.

Pioneers Around the Clock
Datum-Irvine is one of four divisions comprising the Datum group in the United States, and is one of the largest companies devoted solely to time and frequency technology in the world. Each group concentrates on specific segments of the time and frequency marketplace. Datum-Irvine was founded in 1971 as Efratom by Ernst Jechard and Gerhard Huebner, the pioneers who developed the world’s first miniature rubidium atomic oscillator. In 1973, the company moved to California, and in 1983 it was purchased by Ball Corporation of Muncie, Ind. It operated as one of the divisions of the Ball Aerospace Group until 1995, when it became part of Datum. Datum-Irvine now supplies more than 70 percent of the high-precision rubidium atomic clocks used in cellular and personal-communication-services network base stations.

Datum’s eBusiness Solutions group provides secure and auditable time-stamping technology for electronic transactions, time references for computer networks and encryption engines for the distribution and reception of confidential information. Datum-Austin, founded in 1962 and acquired by Datum in 1988, has been designing timing technologies for the military, navigation and telecommunications industries since its beginnings. It offers the NetSyncPlus® family and the TimePieces™ family, the latter a powerful chip-set family of embedded TimePieces™ including a variety of input, output, oscillator, SmarTiming™ and communications chips.

Datum’s Timing, Test & Measurement (TT&M) strategic business unit, headquartered in Beverly, Mass., is a global leader in a variety of applications including timing, testing, verification and/or the measurement of a time- and frequency-based signal. One of these technologies, cesium, forms the basis for the modern definition of time. The use of cesium technology to provide pure, accurate and stable signal outputs is a technical proficiency that few companies have achieved, but one that Datum TT&M has perfected. Datum TT&M is a leading supplier of cesium frequency standards to the global-positioning-system (GPS) satellite constellation. It also provides high-precision frequency and timing standards in a wide range of commercial, high-reliability, military and aerospace applications.

The Craft of Precision
Mass-producing a precision instrument like an atomic clock is no easy task. But in mid-1972, Datum-Irvine (as Efratom) put the first rubidium oscillator units into production, and they became an immediate commercial success. These devices have since been used in a variety of demanding applications for navigation, communication and other time and frequency systems. Government agencies, ground-station networks and the aerospace industry comprised the first customer base. The major applications at that time were communications systems such as Omega/VLF, Loran-C and NAVSTAR GPS; it also found its way into special applications such as instruments, test stations, calibration networks, laboratories, radar, signal generators and analyzers.

During this time, Datum manufactured rubidium oscillators with intensive handwork and the expert craftsmanship required of Swiss watch making. But the labor-intensive hand assembly, aging and testing processes required months to produce each unit. Recognizing these production limitations, Datum spent years refining its oscillator designs and manufacturing processes to simplify and accelerate each major step, while still adhering to incredible timing precision. The biggest benefit of the reworked design and manufacturing was to increase production from hundreds a year to many thousands a year, without any loss in precision.

Typically, the Datum rubidium gas cell atomic clock gains no more than one second every 10 years, and the Datum cesium atomic beam clock is accurate to fractions of a second over 300,000 years. When installed in a telecommunications base station, the rubidium oscillator is usually locked to a cesium GPS reference signal, and is thus disciplined to the same high accuracy of the cesium oscillator. The rubidium oscillator maintains excellent performance when these GPS signals cannot be received due to line-of-sight blockages or heavy interference.

A second hurdle Datum handled successfully is custom design. The majority of its customers are OEMs, which often require special timing-output frequencies, voltage inputs or unique operating temperature ranges. In the past, this meant a hardware redesign whenever a customer wanted a large order of a special configuration. But Datum’s engineering staff switched from a fully analogue architecture to digitally controlled designs with the new X72 rubidium oscillator. Now many features of the oscillator can be changed through firmware modifications. This is a major advance for Datum, and one of the many distinguishing features that separates the X72 from its competitors. This, the newest of Datum’s oscillator designs, includes many innovations: low power consumption, very low height and size, a wide range of operating temperatures from minus-40 degrees Celsius to 85 degrees Celsius and breakthrough pricing. The latter is the result of the imaginative new design, which significantly reduces the number of components and manufacturing steps. The X72 is designed to operate for 20 years before it needs tuning or calibration, which is the reliability and dependability the company’s customers — leading global telecommunications companies —require.

Quality Time
Datum-Irvine offers a complete line of precision frequency-generating components, all based on state-of-the-art, mass-producible technologies. These are sold as components or as part of the systems it designs. The company uses a formal supply-chain-management plan for key customers. This system categorizes components according to the degree of difficulty in obtaining them, and then takes corresponding actions to secure their availability. Ten years ago, Datum-Irvine began implementing quality initiatives, including the best of WCM, total quality management, just-in-time delivery and statistical process control. In 1995, it received ISO 9001 certification. Separate commercial and military production lines are maintained to assure proper adherence to quality standards and product reliability. The company is qualified to MIL-I-45208A and can manufacture to MIL-Q-9858.

Datum-Irvine continues to be actively engaged in research and development to further the technology of precision time and frequency devices, and to improve performance, decrease size and weight, lower costs and achieve even higher reliability. This research incorporates innovative design improvements in electronic circuits so that the company’s rubidium oscillators, test equipment products and systems continue to maintain a position of leadership in this technology. Datum-Irvine has developed and put in place automated equipment and processes to streamline the manufacture of core rubidium components and to provide the company with the greatest manufacturing capacity of rubidium oscillators in the world.

The X72 breakthrough atomic oscillator demonstrates the company’s significant advances in physics miniaturization and integration. As a free-running or disciplined precision reference oscillator, the X72’s low height, small footprint and extended upper operating temperature allow an entire synchronization package to fit into single-slot module. Datum-Irvine will continue to focus on its strength as a full-range supplier of oscillators and miniature atomic clocks. This strategy will maintain its position as the leader of the rubidium-oscillator and timing-solutions market.