Cesium Time and Frequency References

Since 1967, the hyperfine transition frequency of the ground state of the cesium 133 atom has defined the unit second. Our cesium time and frequency references are the most accurate commercial atomic clocks available. Our state-of-the-art facilities manufacture cesium references with accuracies as low as 5E−13, with no systemic frequency drift during the operational life of the unit and no need for calibration. Cesium frequency references are widely deployed as the primary source of time and frequency in a broad range of applications, including timing and metrology, defense, Position Navigation and Time (PNT) systems, telecommunications, data centers and critical infrastructure.

5071A Cesium Primary Time and Frequency Standard

The 5071A is the most accurate commercial atomic clock available. It has an accuracy of less than 5E−13 under all environmental conditions and no deterministic frequency drift. The capabilities and reliability of the 5071A make it the single largest contributor of cesium clocks—more than half of all contributing clocks—to Coordinated Universal Time (UTC). The 5071A is the world’s leading timing solution for strategic defense assets and critical civilian and government infrastructure, with the ability to deliver submicrosecond holdover for months at a time during Global Navigation Satellite System (GNSS) denial.

Key Features
  • < 5E−13 accuracy high-performance models
  • < 1E−12 accuracy standard-performance models
  • Accuracy levels achieved within 30 minutes of startup
  • < 8.5E−13 at 100s high-performance models
  • < 2.7E−12 at 100s standard-performance models
  • < 1E−14 flicker floor high-performance models
  • < 5E−14 flicker floor standard-performance models
  • No deterministic frequency drift
  • 100 kHz, 1, 5 and 10 MHz RF sine wave outputs
  • Three 1 PPS outputs
  • Two 1 PPS inputs to steer to external GNSS receiver or other 1 PPS source
  • AC and DC operating voltages
  • Internal battery back-up for short-term power interruptions
CsIII Model 4310B Cesium Frequency Standard

Our 4310B cesium frequency standard is the smallest, lowest-power and most cost-effective cesium frequency reference available. It has a low-profile, 2U, 19-inch rack-mountable chassis and provides the same stability and accuracy as the standard-performance 5017A. Weighing less than 30 pounds, the 4310B is a portable solution for SATCOM applications and calibration services. The 4310B-R models are also fully CE compliant and provide a total of five 1 PPS outputs.

Key Features
  • < 1E−12 accuracy including environmental conditions
  • Accuracy levels achieved within 30 minutes of startup
  • < 2.7E−11 τ −1/2 Allan deviation (100 s < τ < 100,000 s)
  • < 5E−14 flicker floor
  • No deterministic frequency drift
  • 5 and 10 MHz RF sine wave outputs and 10 MHz 50Ω TTL output
  • Five 1 PPS outputs
  • 1 PPS input to steer to external GNSS receiver or other 1 PPS source
  • AC and DC operating voltages
  • Remote monitoring and control
TimeCesium Primary Reference Source (PRS-4000-4500)

Our autonomous TimeCesium PRSs—PRS-4400 and PRS-4500—are based on the latest cesium III technology. They are designed to generate superior and highly reliable synchronization signals for advanced network services that meet the G.811 and G.811.1 standards. The TimeCesium PRS produces accurate, spectrally pure and stable output signals using a cesium beam tube resonator. It delivers total control of your 5G network synchronization source, enhances network performance, reduces errors in the SONET/SDH payload and prevents upstream network clock errors from propagating across the network.

Key Features
  • State-of-the-art cesium III beam tube technology for 5G networks
  • Autonomous Stratum 1 primary reference source
  • No antenna installation required
  • Front-access ETSI shelf model: PRS-4400
  • Rear-access ANSI shelf model: PRS-4500
  • DS1, E1, 2048 kHz G.703/13, 10 MHz, 5 MHZ, 1.544 MHz and composite clock outputs
  • Enhanced Primary Reference Clock (ePRC) compliant per G.811.1
  • Enhanced Primary Reference Time Clock (ePRTC) compliant when used with TimeProvider® 4100 series and ePRTC license

Data Sheets

5071A Cesium Primary Time and Frequency Standard
4310B-Cesium Frequency Standard
4400-Cesium Primary Reference Source
4500-Cesium Primary Reference Source

Videos

Overview

Since 1967, the hyperfine transition frequency of the ground state of the cesium 133 atom has defined the unit second. Our cesium time and frequency references are the most accurate commercial atomic clocks available. Our state-of-the-art facilities manufacture cesium references with accuracies as low as 5E−13, with no systemic frequency drift during the operational life of the unit and no need for calibration. Cesium frequency references are widely deployed as the primary source of time and frequency in a broad range of applications, including timing and metrology, defense, Position Navigation and Time (PNT) systems, telecommunications, data centers and critical infrastructure.

5071A Cesium Primary Time and Frequency Standard

The 5071A is the most accurate commercial atomic clock available. It has an accuracy of less than 5E−13 under all environmental conditions and no deterministic frequency drift. The capabilities and reliability of the 5071A make it the single largest contributor of cesium clocks—more than half of all contributing clocks—to Coordinated Universal Time (UTC). The 5071A is the world’s leading timing solution for strategic defense assets and critical civilian and government infrastructure, with the ability to deliver submicrosecond holdover for months at a time during Global Navigation Satellite System (GNSS) denial.

Key Features
  • < 5E−13 accuracy high-performance models
  • < 1E−12 accuracy standard-performance models
  • Accuracy levels achieved within 30 minutes of startup
  • < 8.5E−13 at 100s high-performance models
  • < 2.7E−12 at 100s standard-performance models
  • < 1E−14 flicker floor high-performance models
  • < 5E−14 flicker floor standard-performance models
  • No deterministic frequency drift
  • 100 kHz, 1, 5 and 10 MHz RF sine wave outputs
  • Three 1 PPS outputs
  • Two 1 PPS inputs to steer to external GNSS receiver or other 1 PPS source
  • AC and DC operating voltages
  • Internal battery back-up for short-term power interruptions
CsIII Model 4310B Cesium Frequency Standard

Our 4310B cesium frequency standard is the smallest, lowest-power and most cost-effective cesium frequency reference available. It has a low-profile, 2U, 19-inch rack-mountable chassis and provides the same stability and accuracy as the standard-performance 5017A. Weighing less than 30 pounds, the 4310B is a portable solution for SATCOM applications and calibration services. The 4310B-R models are also fully CE compliant and provide a total of five 1 PPS outputs.

Key Features
  • < 1E−12 accuracy including environmental conditions
  • Accuracy levels achieved within 30 minutes of startup
  • < 2.7E−11 τ −1/2 Allan deviation (100 s < τ < 100,000 s)
  • < 5E−14 flicker floor
  • No deterministic frequency drift
  • 5 and 10 MHz RF sine wave outputs and 10 MHz 50Ω TTL output
  • Five 1 PPS outputs
  • 1 PPS input to steer to external GNSS receiver or other 1 PPS source
  • AC and DC operating voltages
  • Remote monitoring and control
TimeCesium Primary Reference Source (PRS-4000-4500)

Our autonomous TimeCesium PRSs—PRS-4400 and PRS-4500—are based on the latest cesium III technology. They are designed to generate superior and highly reliable synchronization signals for advanced network services that meet the G.811 and G.811.1 standards. The TimeCesium PRS produces accurate, spectrally pure and stable output signals using a cesium beam tube resonator. It delivers total control of your 5G network synchronization source, enhances network performance, reduces errors in the SONET/SDH payload and prevents upstream network clock errors from propagating across the network.

Key Features
  • State-of-the-art cesium III beam tube technology for 5G networks
  • Autonomous Stratum 1 primary reference source
  • No antenna installation required
  • Front-access ETSI shelf model: PRS-4400
  • Rear-access ANSI shelf model: PRS-4500
  • DS1, E1, 2048 kHz G.703/13, 10 MHz, 5 MHZ, 1.544 MHz and composite clock outputs
  • Enhanced Primary Reference Clock (ePRC) compliant per G.811.1
  • Enhanced Primary Reference Time Clock (ePRTC) compliant when used with TimeProvider® 4100 series and ePRTC license
Resources

Data Sheets

5071A Cesium Primary Time and Frequency Standard
4310B-Cesium Frequency Standard
4400-Cesium Primary Reference Source
4500-Cesium Primary Reference Source

Videos

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