Agilent 5071A Primary Frequency Standard

Unsurpassed Stability in the Lab or FieldProduct Overview

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Accuracy and stability• Standard Cesium Beam Tube

Accuracy: ±1 3 10 -12

Environmental Stability:

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Improved cesium beam tubeThe Agilent Technologies 5071A primary frequency standard includes animproved cesium beam tube design. The improved tube reduces the effects ofRamsey frequency pulling. Also, new beam optics use cesium more efficiently.The result is improved accuracy and stability, reduced power consumption,and increased tube life.

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The 5071A’s stability and reliability will keep your calibration lab services available. Satellite communications require stablefrequencies that are easily generated bythe 5071A.

The 5071A primary frequency stan-dard has the accuracy and stabilityyou need for both laboratory andfield applications. A stability specifi-cation for 30-day averaging timemeans the 5071A will keep extremelypredictible time and phase for longperiods. Further, the 5071A can beused for long-term averaging of noisysignals such as GPS.

The 5071A is easy to use. No moremanual start-up steps or complicatedadjustments—everything is automatic.A logical menu structure simplifiesfront panel operations, selections,and status reporting. Remote controlfeatures tailor the 5071A for completeoperation and manageability in virtu-ally any location.

The 5071A is a direct descendant of and replacement for the veteran5060A, 5061A and 5061E cesiumstandards. This innovative product is the result of Agilent’s more than 35 years of experience in the preci-sion frequency standard business.

The 5071A—meeting the needs ofleading-edge metrology and cali-bration labsTimekeeping and National StandardsLaboratories verify the stability andaccuracy of their in-house cesiumstandards to Coordinated UniversalTime (UTC), provided by the BureauInternational des Poids et Mesures(BIPM) in Paris. A standard’s accu-racy and reliability determine thequality of service these timekeepinglabs provide. Of even greater concernis the stability of a standard. Stabilitydirectly affects a laboratory’s abilityto deliver timekeeping and calibrationservices to its clients.

The 5071A offers exceptional stabilityand is the first cesium standard tospecify its stability for averagingtimes longer than one day. Theinstrument takes into account envi-ronmental conditions that can heavilyinfluence a cesium standard’s long-term stability. Digital electronics con-tinuously monitor and optimize theinstrument’s operating parameters.

Thus, the 5071A’s response to envi-ronmental conditions such as temper-ature and humidity are virtually elim-inated. The 5071A primary frequencystandard maintains its accuracy andstability, even in unstable environments.

Satellite communicationsStable frequency generation is requiredto transmit and receive signals prop-erly between ground terminals andcommunication satellites. Frequencyflexibility is also needed to adjust forsatellite-to-satellite carrier-frequencydifferences. The 5071A’s state-of-the-art technology produces offset andprimary frequencies with the sameguaranteed stability.

For secure communications, precisetiming synchronization ensures thatencrypted data can be recoveredquickly. Frequency-agile signals alsorequire exact synchronization betweentransmitter and receiver during chan-nel hops.

The 5071A automates the synchro-nization to any external 1-PPS signal,greatly simplifying this aspect ofsatellite communications.

Guaranteed stability keeps the Agilent 5071A working longer for you

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Telephone network synchronizationTelecommunication systems must besynchronized in time and have thesame data rates. If these require-ments are not met, entire frames ofdata may be lost. Data loss is mini-mized when cesium standards areintegrated as master system clocks atthe Stratum 1 and InternationalGateway interface levels. The unit-to-unit frequency accuracy (tracking) ofthe 5071A prevents data loss due todiffering transmission and receptionrates.

Unlike other technologies, the 5071Ahas the reliability required to maxi-mize telecommunication system up-time. Agilent’s record for uniquely-designed, high-quality products isunmatched.

Standard options available with the5071A allow the unit to operate fromredundant 48-V sources and produceeither DS1- or CEPT-compliant clocksignals. See “Telecommunicationsoptions” on page 7 for more details.

The 5071A and GPSThe 5071A primary frequency stan-dard can work very well with a GPStiming receiver to produce and main-tain highly accurate time and fre-quency.

The GPS system provides accuratetime, frequency, and location infor-mation worldwide by means ofmicrowave radio broadcasts from asystem of satellites. Timing accuracyfor the GPS system is based, in largepart, on the accuracy and stability ofa number of 5071A primary fre-quency standards. These standardsare maintained by the GPS system,the US Naval Observatory, and vari-ous timing laboratories around theworld which contribute to UTC, theworld time scale.

Because of their accurate time refer-ence, GPS signals processed by a goodGPS timing receiver, can providehighly accurate time and frequencyoutputs. However, since GPS receiversrely on very low level microwave sig-nals from the satellites, they some-times lose accuracy because of inter-fering signals, local antenna problems,or bad satellite data.

In spite of these problems, a GPS timing receiver can be an excellentbackup and reference to a local5071A primary frequency standard.The GPS receiver provides an inde-pendent reference that can be used to verify the accuracy of a cesiumstandard, or it can be used as a tem-porary backup should the cesiumstandard need repair. The local 5071Astandard has better short-term stabil-ity, better output signal quality, and isnot perturbed by interfering signals,intermittent signal loss, or bad satel-lite data.

With these characteristics, the syn-ergy created by combining a goodquality GPS timing receiver and a5071A primary frequency standardcan produce a highly robust, inex-pensive, and redundant frequencyand time system.

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Exceptional accuracyAn improved cesium beam tube andnew electronics design—known asCesium II Technology—make theAgilent 5071A six times more accuratethan its predecessor, the 5061B. Theintrinsic accuracy of the improvedcesium beam tube assures that any5071A Option 001 will power up towithin ±5 3 10 -13 of the acceptedstandard for frequency. This isachieved under full environmentalconditions in 30 minutes or less—and without the need for any adjust-ments or alignments.

Unsurpassed stabilityAgilent’s Cesium II technology bringsa new level of stability to the cesiumclock. The 5071A’s outstanding speci-fications are a result of this advancedtechnology. The 5071A Option 001high-performance cesium beam tubeguarantees stability to be better than1 part in 1014 for averaging times offive days or greater. The 5071A is thefirst cesium standard to specify sta-bility for averaging times longer than105 seconds (approximately one day).

The 5071A is also the first cesium stan-dard to specify and guarantee a flickerfloor. Flicker door is the point at whichthe standard’s stability (σy (2, τ)) doesnot change with longer averaging. The5071A Option 001 flicker door is guar-anteed to be 1 part in 1014 or better.Long-term measurements at theNational Institute of Standards andTechnology (NIST) show that theflicker floor is typically better than 5 3 10 -15.

Unstable environments are normalfor many cesium standard applica-tions. The 5071A features a numberof microprocessor-controlled servoloops. The 5071A has demonstated amean time between failures (MTBF)of over 100,000 hours, based onactual field repair data which allow itto virtually ignore changes in temper-ature, humidity, and magnetic fields.Under full environmental conditions,the 5071A Option 001 frequencyvaries less than 8 parts in 1014.

The 5071A delivers exceptional per-formance over very long periods oftime, greatly increasing the availabil-ity of critical time and frequencyservices.

Traditional reliabilityHewlett-Packard and AgilentTechnologies have been producingcesium frequency sources and relatedproducts since 1964. Over 100 millionfield operating hours in critical mili-tary and commercial applicationshave proven the reliability of cesiumstandards.

Cesium II technology, because ofadvancements in tube design, auto-mated maintenance, and extensiveuse of digital circuitry, offersimproved reliability over its predeces-sor, the 5061B. Backing up this relia-bility is a 10-year warranty on thestandard cesium beam tube and athree-year warranty for the optionalhigh-performance tube.

Complete repair and maintenanceservices are available at four strategi-cally located service centers world-wide.

Full traceability to NISTAgilent Technologies’ Santa Clara,California lab provides NIST trace-ability to the accuracy measurementsmade on every 5071A. Traceability toNIST is maintained through the NIST-supplied frequency measurement andanalysis system (FMAS). This serviceexceeds the requirements of MIL-STD-45662A and can be a valuabletool in demonstrating traceability toyour customers.

The 5071A’s enhanced cesium beam tubeand electronics package (Cesium II tech-nology) provide increased accuracy andstability.

Cesium II technology delivers unmatched accuracy and stability

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Straightforward operationInternal microprocessor controlmakes start-up and operation of the5071A extremely simple. Once con-nected to an ac or dc power source,the 5071A automatically powers up toits full accuracy specifications. Noadjustments or alignments are neces-sary during power-up or operation forthe life of the cesium tube.

An intuitive menu structure is acces-sible via the front panel LCD displayand keypad. These menus—InstrumentState, Clock Control, Instrument Con-figuration, Event Log, Frequency Offsetand Utilities—logically report statusand facilitate control of the instru-ment. These functions are describedbelow.

Instrument stateOverall status is displayed, includingany warnings in effect. Key instru-ment parameters such as C-field cur-rent, electron multiplier voltage, ionpump current, and cesium beam tubeoven voltage are available. You caninitiate a hard copy report of thisdata on your printer with the push ofa button.

Clock controlSet the time and date, scheduleleapseconds, adjust the epoch time(in 50-ns steps), and automaticallysynchronize the 1-PPS signal towithin 50 ns of an external pulseusing this menu.

Instrument configurationSet the instrument mode (normal orstandby) and assign frequencies (5 or10 MHz) to the two independentlyprogrammable output ports; config-ure the RS-232C data port.

Event logSignificant internal events (powersource changes, hardware failures,warning conditions) are automati-cally recorded with the time and dateof their occurrence. A single key-stroke produces a hard copy on yourprinter for your records.

Frequency offset (settability)Output frequencies may be offset byas much as 1 part in 109 in steps of6.3 parts in 1015. All product stabilityand output specifications apply to theoffset frequency.

UtilitiesThe firmware revision level andcesium beam tube identificationinformation can be displayed.

High-performance cesium beamtube (5071A Option 001)The 5071A Option 001 high-performance cesium beam tube is optimal for the most demandingoperations. The Option 001 tube offersa full-environment accuracy specifica-tion of ±5 3 10 -13—two times betterthan the specification for the standardtube. Stability is also significantlyimproved. The high-performance tubereaches a flicker door of 1 3 10 -14 orbetter, and long-term measurementsat NIST show that the flicker floor istypically better than 5 3 10-15.

Integrated systems and remoteoperationToday, cesium standards are oftenintegrated into telecommunication,satellite communication, or naviga-tion systems as master clocks. Toaccommodate these environments,the 5071A provides complete remotecontrol and monitoring capabilities.Instrument functions and parameterscan be interrogated programmati-cally. Communication is accom-plished via the standard commandsfor programmable instruments (SCPI)language and a dedicated RS-232Cport. Also, a rear panel logic outputcan be programmed to signal whenuser-defined “abnormal” conditionsexist.

For uninterruptible system service,an internal battery provides 45 min-utes of backup in case of ac powerfailure.

Thus, the 5071A can be managed eas-ily even in the most remote locations.

Telecomunications optionsThe 5071A primary frequency stan-dard may be optionally equipped toprovide output frequencies, imped-ances, and signal formats required ofa primary reference clock in moderntelecommunication networks.Configurations are available for bothDS1 and CEPT standards. The 5071Acan also be equipped to operate froma 48-Vdc central office battery.

Clock rates of 1.544 and 2.048 Mb/sare available. Impedance choices and signaling formats for all currentITU-T specifications are also avail-able. All features found in a standard5071A are retained when a 1.544- or2.048-Mb/s option is installed. Thisincludes both programmable 5/10-MHzoutputs and the 1-MHz and 100-kHzoutputs. The 1-PPS output and syncare only available on the front panelof the instrument.

The 5071A Option 048 equips the frequency standard to operate from48 Vdc power. Two independent 48-volt power sources may be sup-plied. The power sources must be ofthe same polarity, but either polaritymay be used.

Each power source in the 5071AOption 048 is isolated and fully fuse-protected. The frequency standarddraws power from the source withthe higher voltage. Upon source fail-ure the frequency standard will auto-matically switch to the good source—ensuring uninterrupted operation.

The 5071A Option 048 automaticallyuses a 48-Vdc source if one is present.The instrument will attempt to use acpower if no dc source is available.The internal battery normally sup-plied with the 5071A is not availablewhen Option 048 is installed.

For further details, see “Orderinginformation” on back page.

Ease of use and versatility

Sinusoidal output characteristics (all located on rear panel)

Parameter Ports 1 & 2 * 1 MHz, 100 kHz

Amplitude into 50 Ω load > 1 Vrms > 1 Vrms

Isolation2 between ports >110 dB (typical) not specified

Harmonic signals (typical)

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Time standardClock display24-hour red LED display of hours, minutes,and seconds

Clock 1-PPS outputsAll outputs are isolated from each other

Amplitude: ≥2.4 V into 50 Ω(output levels are TTL compatible)

Width: 20 µsRise time: 109 volts/second at 1.5 volts)Jitter:

EnvironmentalProduction units have passed type testingas follows: Temperature:

Operating: 0 to 55 °C Non-operating: -40 to +70 °C

Humidity: 0 to 95% relative humidity (at maximumtemperature of 45 °C)

Atmospheric pressure: < 1 x 10-13 change in frequency for pres-sure change down to 19 kPa (equivalentto an altitude of about 12.2 km)

Shock and vibration: MIL-T-28800D, Type III, Class 5; Hammer Blow Shock Test, MIL-S-901C,

Grade A, Class 1, Type A EMI: CISPR 22, Class A; CISPR 11, Group 1,

Class A; MIL-STD-461C, Part 7, Class B dc magnetic field: up to 7.8 Gauss

WeightNet weight: 30 kgShipping weight: 40 kg

DimensionsHeight133.4 mm

Width425.5 mm

Depth523.9 mm

This includes spacers which extend 25.4 mm beyond the rear panel.

WarrantyElectronics1 year

Cesium beam tubeStandard tube: 10 yearsHigh-performance tube(Option 001): 3 years

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Accessories furnishedPower cord:

180 cm detachable

dc input connector:part number 1251-0126(5 contact), Cannon MS3106E-14S-5S

(series ME)

Cabinet front handles kit

Accessories availableRack Slides: (see options for other rackmounting hardware)

Fixed slides: order part number 1494-0059

Application note availableApplication note 1289, The Science ofTimekeeping

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Agilent 5071A primary frequency standard options $58,167001 High-performance cesium beam tube $12,932

OB2 One extra set of operating and programming documentation $41

OBW Assembly-level service manual (Contact your local Agilent $111Sales Office for pricing and availability.)

908 Rack flange kit $42Use for mounting the 5071A when front handles are not to be used. Also available under part number 5062-3977. WARNING: Do not mount this product by the rack flanges alone. Always use a shelf, rails, or slides.

913 Rack flange kit $42Use with front handles supplied with 5071A. Also available under part number 5062-3983. WARNING: Do not mount this product by the rack flanges alone. Always use a shelf, rails, or slides.

W30 Warranty $1,653Two additional years of “Return to Agilent” service on the electronics (the cesium beam tube is warranted separately). This option adds to the basic electronics warranty to provide a total of three years of coverage.

W50 Warranty $3,306Four additional years of “Return to Agilent” service on the electronics (the cesium beam tube is warranted separately). This option adds to the basic electronics warranty to provide a total of five years of coverage.

Ordering information

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Product specifications and descriptions in thisdocument subject to change without notice.

Copyright © 1998, 2000 Agilent TechnologiesPrinted in U.S.A. 10/005968-1862EUS

Telecommunications options048 48-Vdc Power $528

This option equips the frequency standard to operate from 48-Vdc nominal power. The range that the frequency standard will accept is 40-58 Vdc. Maximum dc power consumption is 100 W. Two independent 48-volt power sources may be sup-plied. The power sources must be of the same polarity but either polarity may be used. The instrument automatically uses a 48-Vdc source if one is present. If no dc source is available, the instrument will attempt to use ac power. The internal battery normally supplied with the 5071A is not available when Option 048 is installed.

The telecom signal options all contain the following outputs:• 8 kHz frame sync in (TTL level into 50 Ω) • 8 kHz frame sync out (TTL level into 50 Ω) • Sync out (Telecommunications rate 1.544 or 2.048 Mbps)

(TTL level into 50 Ω) • Sync out (1.544 or 2.048 MHz), per G.703-10.

In addition, each option has a framed output whose characteristics are determined by the following option numbers. The telecommunications signal options comply with ITU recommendations G703 and G704 for electrical signal characteristics and formatted content.

104 1.544 Mbps, 100 Ω balanced, super frame (D4) $2,111105 1.544 Mbps, 100 Ω balanced, extended super frame (ESF) $2,111220 2.048 Mbps, 120 Ω balanced, common channel signaling $2,111221 2.048 Mbps, 120 Ω balanced, channel associated signaling $2,111222 2.048 Mbps, 120 Ω balanced, channel associated signaling

with CRC4 $2,111270 2.048 Mbps, 75 Ω unbalanced, common channel signaling $2,111271 2.048 Mbps, 75 Ω unbalanced, channel associated signaling $2,111272 2.048 Mbps, 75 Ω unbalanced, channel associated signaling

with CRC4 $2,111