Datum Introduces a Portable Ultra Stable VXIbus Rubidium Frequency Reference.

SAN JOSE, Calif.--(BUSINESS WIRE)--Aug. 24, 1998--Datum Inc. Monday announced the VXIbus Rubidium Frequency Reference module.

This double wide C-size VXI module offers an ultra stable frequency reference for automatic test systems, primarily those devoted to testing and calibrating RF systems. The module's internal rubidium oscillator is automatically calibrated to the orbital atomic clocks in the Global Positioning System (GPS) satellites.

The actual 10 MHz RF reference output signals are derived from a low phase noise quartz crystal oscillator that is phase locked to the master rubidium oscillator, and distributed as 10 MHz sine wave or TTL frequency outputs. The accuracy of the frequency reference signals is derived from GPS, while stability is a result of the master rubidium oscillator, and low phase noise is a product of the disciplined quartz tracking oscillator.

"Our customers have presented us with the seemingly conflicting requirements of an RF reference system with high accuracy, extreme stability and low phase noise, all in a modular portable package. Modem RF systems rely on very low phase noise components and, therefore, low phase noise test equipment. We are pleased we were able to meet all of these needs in this attractively priced VXI module," said Dave Robinson, president of Datum Inc. Bancomm-Timing Division.

The VXIbus Rubidium module provides eight sine wave or TTL 10 MHz isolated outputs. Frequency calibration is via GPS tracking (receiver and antenna supplied) or an external 10 MHz calibration input. In addition to the frequency reference functions, the module supports a wide variety of standard timing functions.

It acquires time from either GPS tracking or an input IRIG A or B time code. If the input time source is lost or unavailable, time is maintained in a flywheel state based on the internal rubidium oscillator.

The internal clock operates with 100 nanosecond resolution. Absolute accuracy is better than 1 microsecond relative to UTC/USNO (Universal Time Coordinated/U.S. Navy Observatory). A synchronous IRIG time code output is provided. External events, as defined by an input TTL pulse, can be time tagged with 10 nanosecond resolution.

Communication with the VXIbus Rubidium module is both message based and register based, preserving backwards compatibility with the Datum VRFS (VXIbus Rubidium Frequency Standard) predecessor module, while permitting low latency time transfers. The module generates user-enabled interrupts based on defined timing events from the module.

The VXIbus Rubidium Frequency Reference module is available now with prices starting around $9,950.

Founded in 1969, Datum designs, manufactures and markets a wide variety of high performance time and frequency products used to synchronize the flow of information in enterprise computing and telecommunications networks. In addition, Datum is a leading supplier of precise timing products for space, scientific and industrial test and measurement applications.

For additional information on the VXIbus Rubidium Frequency Reference module or Datum's family of precision time and frequency products, contact: Datum Inc. Bancomm-Timing Division, 6781 Via Del Oro, San Jose, Calif. 95119-1360, telephone [phone], fax [phone] or e-mail [e-mail].

For corporate or investor information on Datum, contact Datum, David A. Young, chief financial officer, telephone [phone] or Morgen-Walke Associates, Chris Danne, Todd Friedman or Doug Sherk on telephone [phone] or Josh Passman on telephone [phone] or 212/850-5698.

For editorial information on Datum Bancomm-Timing Division, contact: The Huffer Group Inc., Jennifer Huffer, 19700 Fairchild, Suite 380, Irvine, Calif. 92612, telephone [phone], fax [phone] or e-mail [e-mail].

    CONTACT:  The Huffer Group Inc.
               P. Jennifer Huffer, 949/251-9414
               E-mail: [e-mail]
                  or
               Datum Bancomm-Timing Division
               Mitch Stone, 408/578-4161
               E-mail: [e-mail]