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Precision GPS/GNSS based NTP Network Time Servers

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NFS-220 Precision Time & Frequency Standard

The NFS-220 / NFS-220 PLUS units are precision time and frequency standards that use a GPS disciplined precision oscillator from which industry standard time and frequency signals are derived. Applications include WI-FI, Wi-Max, satellite communications and military communication applications.

The NFS-220 / NFS-220 PLUS units are precision time and frequency standards that use a high performance 16 channel GPS receiver to define a precise time standard and hence means to discipline a precision oscillator from which industry standard time and frequency signals are derived. This is supplemented by an automatic position-averaging feature that enables the best use of GPS when operating in a fixed location.

The units are designed for use in WI-FI, Wi-Max, satellite communications, telecommunications and military communication applications requiring exceptional stability and low phase noise.  Both units provide an array of front panel real-time status indicators with the NFS-220 Plus version also incorporating a high visibility, Time of Year Display in the front panel.

An internal back up oscillator is continuously calibrated to GPS using an advanced algorithm, providing optimal frequency control of the oscillator, ensuring that the highest time and frequency accuracy is maintained if satellite tracking is lost.  

Base level units units provide a precision OCXO frequency standard, while TCXO and Rubidium oscillators are available to deliver a variety of price and performance options. A combination option employing a low noise OCXO phase locked to a  rubidium is also available, offering the low noise characteristic of an OCXO with the long term stability of a rubidium.

Typical Applications

The NFS 220 is commonly specified where precision, reliability and cyber security are key considerations. These precision units are thoroughly proven worldwide as reliable and accurate time and frequency references.

NFS-220 : GPS Referenced Precision Time & Frequency Standard

NFS-220 / NFS-220 Plus datasheet



Real time “at a glance” status indication is available via the front panel LED’s together with a large time, day and year display on the NFS-200 Plus variant. System configuration and status is readily integrated with other time management systems

using the Ethernet and serial ports.

The units are designed for simple integration into military platforms by allowing synchronization from Have Quick time codes, available on military SA-ASM GPS receivers such as the DAGR or PLGR. They also generate Have Quick and 1PPS signals compatible with ICD-GPS-060.

The integrated Ethernet interface provides Network Time Protocol (NTP) synchronization over a network with a built in web server that facilitates setup, control and logging using a standard web browser such as Internet Explorer. Simple Network Management Protocol (SNMP) allows straight forward integration with industry standard network management systems.

Three 1PPS time mark outputs are provided together with a unique feature that allows precisely controlled delays to be

inserted into these outputs to compensate for cable and other propagation delays. Compensation delay is independent for each output and has <1ns resolution.

Serial time code outputs are provided to allow time synchronization to be distributed to computers, displays, and other

equipment requiring precision time. Two outputs are dedicated to Have Quick time code.

Two outputs (one modulated, one DC level shift) may be user selected from IRIG A, IRIG B, IRIG E, IRIG G.

Four low phase noise 10 MHz sine wave outputs from the disciplined oscillator are provided. Signal amplitude is software programmable.  

All outputs are provided with activity detectors. Loss of any output is indicated by means of a individual front panel alarm LED as well as through the network interface or a discrete alarm output.

NFS220 Plus Precision Frequency Standard 10MHz Frequency Standard


•   16 Channel GPS Receiver or ICD-GPS-060 Have Quick/1PPS input references

•   20 Real-time Front Panel Status LEDs and optional high visibility Time of Year Display (NFS-220 Plus)

•   Choice of five disciplined oscillators : TCXO, OCXO, Rubidium, High Stability Rubidium, Rubidium & OCXO

•   High Stability Time and Frequency outputs - Advanced proprietary oscillator control algorithm

•   1U 19” rack mount

•   Network Interface for remote management and NTP server


•   3 x 1PPS outputs with propagation delay compensation

•   Multiple time code outputs (IRIG B, A, E, G) DCLS & Modulated

•   4 x 10 MHz Sine wave outputs

•   Have Quick time code

    •   NTP Time (NTP v3 with SNMP v1)

NFS-220 Military Frequency Standards NFS-220 Communications Frequency Standards