Novatech 1450B User manual

NOVATECHINSTRUMENTS 1 1450B Manual, 3-Aug-2015
INSTRUMENTS
Model 1450B
Disciplined Rubidium FrequencyStandard
Section Page Contents
1.0. . . . . . . . . . . . . . . . . . . . . . . . . . .. . 2. . . . . . . . . . . . . . . . . . . . . . . . . Description
2.0. . . . . . . . . . . . . . . . . . . . . . . . . . .. . 2. . . . . . . . . . . . . . . . . . . . . . . Specifications
3.0. . . . . . . . . . . . . . . . . . . . . . . . . . .. . 3. . . . . . . . . . . . . . . . . . . . . . . . . .Installation
4.0. . . . . . . . . . . . . . . . . . . . . . . . . . .. . 3. . . . . . . . . . . . . . . . . . . . . . . . . . .Operation
5.0. . . . . . . . . . . . . . . . . . . . . . . . . . .. . 3. . . . . . . . . . . . . . . . . . . . . . 1pps Operation
6.0. . . . . . . . . . . . . . . . . . . . . . . . . . .. . 4. . . . . . . PerformanceTest and Calibration
7.0. . . . . . . . . . . . . . . . . . . . . . . . . . .. . 6. . . . . . . . . . . . . . . . . . . . . . . . . . .Warranty

NOVATECHINSTRUMENTS 2 1450B Manual, 3-Aug-2015
1.0 DESCRIPTION
1.1 The Model 1450B is arubidium frequency stan-
dard which can be disciplined toan external1pps
(one pulse persecond) referencesignal. This1pps is
commonly derived from primary, or otherstandards,
such as GPS(global positioning satellite).When dis-
ciplinedto 1pps, the1450B providesprimary stan-
dard accuracyand stability.
1.2 The1450B provides onefixedfrequencysine
wave output of 10MHz and up to 8additional auxil-
iary outputsthat can be fixed sine or TTL or synthe-
sized sine orTTL. The 1450B is particularly useful
in applications which requirenon-standard or cus-
tomerspecifiedfrequencies. The auxiliary outputs
arelocked to the internalrubidium oscillator.
1.3 The most recentversion of this manualcan be
found on Novatech Instruments, Inc. web site.
2.0 SPECIFICATIONS
2.1 FREQUENCYSTABILITY (∆f/f, Typical)
ShortTerm: t=1s <3x10-11
t=10s <1x10-11
t=100s <3x10-12
Aging: Monthly <±5x10-11 after1 month
Yearly <±5x10-10 after3 months
Holdover (24Hours, ±2oC):<±1x10-11 (<±1µs after
>10x 1pps tracking time constant)
Temperature:+5 to +45oC <±1x10-10
Line Voltage:±10% <±5x10-12
2.2 FREQUENCYACCURACY
At shipment: <=±5x10-11 at 20oC.
Retrace: <=±5x10-11 from last frequency after
1hour ON and 24hours OFF (constant environment).
2.3 FIXEDSINEWAVE OUTPUTS
10MHz, 1VRMS ±0.25VRMS into 50Ω.
2.4 SYNTHESIZEDSINEWAVE OUTPUT
Frequencyprogrammable from 100Hz to 50MHz in
0.1Hz steps.
Amplitude: 1VRMS±0.25VRMS at10MHz into 50Ω
(±3dB from100Hz to 50MHz,referencedto
10MHz).
Phase Noise: Typical, <-140dBc,10kHz offset,
1MHz output.
Harmonics: Typical <-45dBc, spurious: <-55dBc.
2.5 SPECTRAL PURITY (10MHzfixed output,
typical)
Harmonic<-25dBc.
Spurious/Non-Harmonic/Sub-Harmonic: <-45dBc.
2.6 PHASE NOISE (Typical, 10MHz output, 50Ω)
Frequency Offset dBc
1Hz -70
10Hz -90
100Hz -120
1kHz -140
10kHz -140
2.7 1pps IN and OUT
1pps IN:DC-coupled, acceptsTTL or CMOS. 1pps
OUT: TTL, 133µsnegativepulse width. Typical
outputjitter: 20ns peak-peak (1minute measure-
ment time).
2.8 ENVIRONMENTAL
Temperature:+0oC to +50oC operating.
Humidity: 80% to 31oC, decreasing linearlyto
50% at 40oC.
2.9 SIZE
3.47” H, 16.73”W, 12.0” D, standard 19” rack.
2.10 CONNECTORS
BNCson rearpanelforfixed10MHz sine output
1pps input, 1pps outputand eight auxiliary outputs.
2.11 LINE POWER
120/240VAC±10%,50/60Hz.30VA (50VAmax
during warmup <20minutes). (internal linevoltage
switch)
2.12 FRONT PANELINDICATORS
POWER OK: AC power is applied and on.
RUBIDIUM LOCK:Green:Oscillatoris locked.
Red: Warm-up.
1 PPS LOCK: Locked to and tracking a 1pps input.

NOVATECHINSTRUMENTS 3 1450B Manual, 3-Aug-2015
2.13 ACCESSORY
GPS1: Matching GPSsmartantenna system.
3.0 INSTALLATION
WARNING:
The 1450B line power input receptacleis provided
with a 3-wirecord. Do not defeat the grounded
conductor.
3.1 PowerConnection. Verifythat therearpanel
indicates your line power(120VAC or 240VAC
50Hz/60Hz). Connect theprovided 3-wireline cord
to your powersource. The power switchis built-in
to theinput moduleon the rearpanel. Linevoltage is
selected by an internalswitch and set at the factory.
3.2 1450BInstallation. The1450Brequires no user
setup beyond the application of line powerand con-
nection to your application. Connect your 50Ωcoax-
ial cables to theappropriate frontpanelBNC. See
below for1pps connections and use.
NOTE:
If you plan to use your 1450B as part of a
calibration systemor house standard, it is suggested
that it be powered from an uninterruptable power
supply(UPS) (along with your 1pps source, if used).
4.0 OPERATION
4.1 Poweron. Afterpower isapplied, the1450B
POWEROK LED will illuminate green. This indi-
catesthat the applied linepower is within tolerance
and the unit isfunctioning.
4.2 Rubidium Warm-up. Afterpoweris applied,
the 1450B willtakeup to 20 minutes to reach
Rubidium Lock. DuringRubidium warm-up time,
the frontpanel LED labelled RUBIDIUM LOCK
willilluminatered. Whenthe lock has been
achieved (∆f/f<±1x10-8), this LEDwillilluminate
green. This function is independent of 1pps tracking.
NOTE:
During the Rubidium locking process, thefront
panel RUBIDIUM LOCK LED may switchbetween
red and green. A steady green indicates LOCK.
4.3 Proper operation in stand-alone mode, without
a1pps connection, is indicated by agreen POWER
OK LED and agreen RUBIDIUM LOCK LED.
The 1pps LED will remain off.
NOTE:
The 1450B willmeet the specified accuracywithin a
fewhours after power-up. For applications
requiring verification of long-term stability, the
periods shown in the specifications will haveto be
met.
4.4 See thesection “1pps Operation,”below, for
details on 1pps connections and operation.
5.0 1pps OPERATION
5.1 1ppsIn andOut. The 1450B is equipped with
rear panel BNC receptacleswhich accept a1pps
inputand provide a1pps output. Use of 1pps allows
synchronization of multiple1450B, aswellas pro-
viding ameans of auto-calibration.
5.2 The1450B will accept along-termstable1pps
signal, typically derivedfrom aGPS(global posi-
tioning system)receiverorfrom anotherfrequency
standard.It will auto-adapt to the supplied 1pps and
adjust theinternal Rubidium Oscillator to match the
long term average frequency derivedfrom the1pps.
The auto-adaptivealgorithm selects thebest tuning
timeconstant based upon thestability of your sup-
plied 1pps.
5.3 For low-jitter 1pps inputs (<20ns),the approxi-
mate tuning time constant will be 1,000 seconds.A
typical timing receiver system, such as theGPS1
(with approximately 100ns peak-peak1pps jitter),
requires atimeconstant of approximately 10,000
seconds (about 3 hours) foroptimum tracking.
5.4 For noisier1pps inputs,thetime constant may
increase to 100,000 seconds. Ifthe input istoo
noisy, the 1 PPSLOCK light willnot illuminate.

NOVATECHINSTRUMENTS 4 1450B Manual, 3-Aug-2015
5.5 Proper operation whentracking a1pps signalis
indicated by allthree front panel LEDs illuminated
green.
NOTE:
Due to theselong time constants necessary to track
a 1pps input, temperature variationscan cause
fluctuations in the relative phase of the 10MHz
output and the 1pps output.
NOTE:
The ∆f/f tracking range of the internal Rubidium
oscillatoris approximately ±1x10-8. Ifyour 1pps
sourceis in error, but within theselimits, the 1450B
will adjust to your source.This allows multiple units
to be synchronized even in theabsenceofan abso-
lute reference.
NOTE:
The auto-adaptive frequency adjustment has a
resolution of ±5.12x10-13.
CAUTION:
Do notconnect the 1pps input and1pps outputon an
instrumenttogether. Thiswillforcetheinstrument to
tracka moving value and reach its adjustment limit.
5.6 The 1450B is configuredforautomatic self-cali-
bration. Whencontinuously connected to astable
1pps source, itwillauto-save thedisciplined fre-
quency value into non-volatile calibration memory
every24 hours. The last-saved valuewillbe used at
next power on or when 1pps islost. The1pps output
of acalibrated and tracking 1450Bhas lowerjitter
than atypical GPSreceiver makingitsuitablefor
use as amaster oscillator forfurther1pps systems.
6.0 PERFORMANCETEST&
CALIBRATION
6.1 The performance testdetailedbelow verifies
that the1450Baccuracyisequal to theaccuracy
achieved immediately aftercalibration. Prior to per-
forming this testit is recommended thatthe1450B
be calibrated.
NOTE:
Thereareno periodic user adjustments requiredfor
operation of the 1450B. When necessary, calibra-
tion should be performed “closed-case” using an
external 1pps source.
NOTE:
The unit under test orcalibration mustremain
undisturbedduring the calibration period. Changes
in environmental conditions(temperature, electric
field, magneticfield or physicalorientation) affect
the calibration. If possible, calibration should be
performed atthe application site.
6.2 Calibration: Calibration of the 1450B should
be performed “closed-case”using an external 1pps
source.Closed-case calibration is obtained by con-
necting the 1450B 1pps input toaknownstableand
accurate(betterthan 1 x10^11) 1pps source.Verify
that the three front panel LEDsareallilluminated
green. Astable 1pps source will allow this illumina-
tion within15 minutesafter connection. Leave the
unittracking the1pps external signalin astable
environment for aminimum of 5days. During this
timethe internal auto-adaptive algorithm will mea-
sure and qualify the1pps source, adjustingthe fre-
quencyto thelong term average ofthe 1pps source.
Whencontinuouslyconnected to astable 1pps
source,the 1450Bwill auto-save the disciplinedfre-
quencyvalue into non-volatile calibration memory
every 24 hours.
NOTE:
Calibration and verification ofthefrequencyand
frequency stability of the 1450B requires a
laboratoryenvironmentof 23oC ±3oC.

NOVATECHINSTRUMENTS 5 1450B Manual, 3-Aug-2015
6.3 See Table 3for alist of recommendedtest
equipment toperformthefollowing measurements.
6.4 Verify Frequency Accuracy. To verify the fre-
quency ofthe1450B,setthefrequency counterto
display12-digits of resolution. Thefrequency
countermust usean external time baseof accuracy
better than ±1x10-11.
6.5 Verifythat the frequency and amplitude of the
fixed 10MHz sinewave outputis within thetoler-
ancesas shown inTable 4. Allowthecounter to
averageseveral readings.Acountertimeconstant
of 1000seconds or longer is recommended. The
error limits shown do not include timebaseor
countererrors.
6.6 Amplitude Verification. Establish ameasure-
ment function of Volts RMS on theoscilloscope.
Connect a50Ωcoaxialcablefrom the1450Btothe
oscilloscope (set to 50Ωtermination) Verify an
amplitudeof 1.0Vrms±0.25Vrms on the fixed
10MHz sine wave output.
6.7 To verify the Auxiliary output signals seethe
option addendum for eachspecific1450B configu-
ration..
6.8 This concludestheverification test of the
1450B.
Table3:Recommended Test Equipment
Item Minimum Specification Recommended
Oscilloscope 300MHz,50Ω
termination Tektronix TDS3032B
Frequency
Counter 100MHz,12- digits. HP53132A
Counter Time
Base <±1x10-11 Novatech Instruments, Inc.
Model2965AR
with GPS1smart
antenna.
Table4: Frequency TestPoints
Frequency ∆f Voltage Tolerance
10MHz ±500µHz 1.0Vrms±0.25Vrms

NOVATECHINSTRUMENTS 6 1450B Manual, 3-Aug-2015
WARRANTY
NOVATECH INSTRUMENTSwarrantsthatallinstruments itmanufacturesarefreefrom defectsin
materialand workmanshipand agrees to replaceor repair any instrument found defective during a period
of oneyearfrom date ofshipment to original purchaser.
This warrantyis limited toreplacing orrepairing defectiveinstrumentsthat have been returnedby
purchaser,at thepurchaser's expense, to NOVATECH INSTRUMENTSand thathavenot been
subjectedto misuse,neglect, improper installation, repair alteration oraccident. NOVATECH
INSTRUMENTS shall have the sole right to final determination regarding the existenceand causeof a
defect.
This warranty is in lieu of any other warranty, either expressed or implied, including but not limited to
any warranty of merchantability orfitness foraparticular purpose. Inno eventshall seller beliable for
collateral or consequential damages. Some states do not allowlimitations or exclusion ofconsequential
damages so this limitation may not apply to you.
All instrumentsmanufacturedby NOVATECH INSTRUMENTS should be inspectedas soon as they are
receivedby the purchaser.If an instrument is damaged inshipment the purchasershould immediately file
aclaim withthetransportation company. Any instrumentreturnedtoNOVATECH INSTRUMENTS
should be shipped in its originalshipping containeror otherrigidcontainerand supportedwith adequate
shock absorbing material.
This warranty constitutesthe full understanding between NOVATECH INSTRUMENTSand the
purchaserand no agreement extending or modifying itwillbebinding on NOVATECH
INSTRUMENTS unlessmade in writing and signed by anauthorized official ofNOVATECH
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