Atec Fluke-910, Fluke-910R User Manual

910/910R GPS

GPS­Receiver

Phase
comparator

Local
oscillator
(VCO)

Reference Out (10 MHz)

Controlled Frequency Standards

The cesium controlled frequency standard that uses

GPS technology and connectivity to provide primary

standard traceability from any location

The 910 and 910R GPS-con­trolled frequency standards
deliver a precision frequency
and pulse-per-second time
“reference which, with its many
connectivity options, can be
installed, monitored and man­aged from virtually any location.
Both models receive their long­term frequency stability from
the built-in cesium standards in
the GPS-satellite array, yet can
also provide a very high short­term stability from the built-in
oven controlled crystal oscillator
(OCXO) or rubidium oscillator (Rb).
Both the 910 and 910R are
fully traceable and extremely
accurate frequency standards
and are ideally suited for use
in many applications, including
telecommunications, calibration
and automatic test systems.

Unique traceability feature
means no more re-calibrations

Off-air frequency standards
have existed for several years.
But until now, they all have had
the same internal architecture
(Figure 1). The unit is, in effect,
a “black box,” with an antenna
input and a frequency output.
The local oscillators con­trol process (disciplining) is

hidden from the user. Typically,
users have used another fre­quency reference (for example,
a rubidium standard), a timer/
counter and a PC for logging the
deviation between the “black
box” and the frequency reference.
The concept of traceability
requires an unbroken chain of
comparisons to international
standards, on a continuing basis,
where all comparisons produce
documented results with stated
uncertainty.
Now, for the first time, a docu­menting frequency comparator
and a very stable secondary
standard are united within the
same instrument together with
the GPS receiver.
The received GPS signal is
measured continuously against
the local oscillator. Phase and
frequency deviation is stored

Figure 1. A typical “black box GPS receiver” (antenna in - reference out). Internal oscillator
offset and adjustments are invisible to the user.

Technical Data

internally and can at any time
be transferred to any PC directly
from the 910/910R or, via the
optional Ethernet interface, from
or to almost anywhere. Then by
using the GPSViewTM software
supplied with every model, a
printout of the traceability record
can be obtained. The unbroken
calibration history chain—day
by day—is maintained in the
non-volatile memory for several
years, with the current 24-hour
mean offset being displayed con­tinuously on the front panels LCD
display.
Such unique traceability to
primary standards means that
the 910 and 910R never need
to be away for re-calibration.
Thanks to this design, the very
high stability built-in rubidium
or OCXO oscillator is continuously
calibrated to the primary freq­uency standards in the US
Observatory and ultimately
UTC, in both operating modes,
disciplined or manual hold-over.

Two high-stability models to
meet your application, and
fit your budget

Fluke Calibration offers two
standard models

in its controlled
frequency standards range; the
very-high stability 910R with its
built-in rubidium atomic clock
as the local oscillator, and the
affordable 910 with its high
stability local oven controlled
crystal oscillator.

Naval

to

GPS­Receiver

High resolution
counter

Measurement
storage

(Calibration data)

Microprocessor

Rubidium
or OCXO
oscillator

Front panel display of frequency offset

1 pps Out

Reference Out (10 MHz)

To PC (RS232)

1pps

Optional Ethernet
interface

Figure 2. The Fluke Calibration 910 and 910R have built-in comparison between the GPS receiver and the internal oscillator. The frequency
offset is displayed and stored and a traceability record can be produced at any time.

Up to 13 outputs, maximizing
cost efficiency

Both models come with one 5 MHz
and five 10 MHz sinewave
outputs as standard. A one
pulse-per-second output is also
included.
If your application requires
more outputs—for example, if
several other instruments need
to be supplied from the same
frequency standard—option 70
allows you to mount five more
10 MHz outputs. Alternatively,
option 72 allows you to expand
your instrument to give five
extra 2.048 MHz outputs, which
is particularly useful in many
telecoms applications. Option
73

provides five extra 13 MHz

outputs,

the standard frequency
for GSM base station master
clocks. Another variant on output
configuration is offered through
option 71, which gives the
instrument an additional four
sine wave outputs of 10 MHz,
5 MHz, 1 MHz and 0.1 Hz, plus a

0.1 MHz square wave output.
And finally, option 75 allows
you to define your own pulse
frequency output.

Central or remote monitoring,
management and data col­lection, using the 910/910R
Ethernet-port

The 910 and 910R can both be
fitted with an optional Ethernet
communication interface (option

76) which enables on-line
access

. Using the GPSView

software supplied, it is possible

TM

to monitor both instrument and
GPS status, or even collect cali­bration data, via the internet or
any Local Area Network.
With Ethernet interface con­nectivity, distances to which
data can be transmitted become
unlimited, unlike that of any
standard GPIB or RS-232 inter­terface, thereby allowing the
910/910R to be monitored from
practically anywhere.
This means that the metro­logist or lab technician no
longer

requires a ‘floating’
laptop PC to directly perform
instrument management tasks,
as this can now be achieved
from any desktop PC, from
any location inside or outside
the calibration laboratory. It
also allows data from multiple
instruments to be simultane­ously viewed in real time.

Two high-stability operating
modes to suit your application

Most users prefer automatic
adjustment (known as disciplin­ing) of their frequency standard,
to fully eliminate long-term
frequency changes (aging).
This disciplined mode is also
the default mode in the 910
and 910R. As long as there is a
valid satellite signal, the internal
local oscillator is monitored and
adjusted and the mean 24-hour
frequency offset is always
virtually zero. However, in this
mode, the inherent short-to­medium term stability of all local
oscillators,

except rubidium, is

compromised. This is true for all
GPS frequency

references. The
received GPS signal has rela­tively large short-term frequency
variations, due to variations in
atmospheric conditions. This
means that when using the
received GPS signal for disciplin­ing the 910 (OXCO), the stability
is reduced a little for

averaging
times of 100 s to 1000 s.
In this mode, the frequency
deviation between the inter­nal timebase oscillator and the
received GPS-signal is used to
continuously adjust the oscillator
(disciplining). The resulting fre­quency offset and adjustment data
is stored in non-volatile memory
every 24-hours, to enable print­out of the traceability record. The
actual frequency offset (24h mean
value) is calculated and displayed
on the front panel.
Some applications demand
superior short-medium term
stability, especially for jitter and
wander measurements in digital
telecommunication networks.
The unique manual hold-over
mode makes it possible to switch
over temporarily from disciplined
to hold-over mode during the
actual measurement, thereby
achieving a superior frequency
accuracy at the start of the mea­surement and a superior stability
through the measurement.
Here, the internal oscilla­tor is not adjusted. This mode is
normally automatically entered
when there is no usable received
GPS-signal. This mode can also

2 Fluke Calibration 910/910R GPS Controlled Frequency Standards

be selected manually by activat­ing the Manual Hold-Over Key. If
Manual hold-over is set together
with a valid received GPS signal,
the actual frequency offset is
calculated, displayed and stored
in non-volatile memory every
24-hours.
For the ultra-stable rubidium
oscillator in the 910R, there
is no measurable difference
between the stability in
plined and hold-over mode,

disci-

for

averaging times up to 1000 s.

Designed for portability too

When using manual hold-over
mode, the 910 or 910R act as a
stand-alone OCXO or rubidium
frequency standard. This means
that one typical drawback of
a GPS receiver, lack of porta­bility, is eliminated. A typical
GPS receiver needs hours to
lock after a change of location,
whereas the 910 and 910R are
up and running after just ten
minutes.

Figure 3. GPSView can print a calibration protocol at any time.

910/910R specications

GPSView Software

GPSView is a Windows
95/98/2000/NT program that
communicates with the GPS­controlled frequency standard.
Its main purpose is to provide a
traceable calibration document
based on the 24-hour frequency
offset values, internally stored
in the non-volatile memory of
model 910/910R

(Figure 3)

.

It is only necessary to
download data to a PC to the
910/910R once every second
year to obtain an unbroken
traceability chain since first use.
For performance analysis over a
shorter period and for short-term
phase variation, data can be
obtained over the latest forty­day period.

From GPSView, the user can
control the operating mode (Dis­ciplined or Hold-Over), and lock
the front panel to prevent unin­tended change via the Manual
Hold-Over Key. The user can also
set the optional pulse

output

frequency and duty cycle.

910R (GPS-Rb)

Frequency stability -
locked to GPS

Frequency offset (24h mean):

-12

< 1 x 10

Short term (Allan dev.):

< 1 x 10
< 3 x 10
< 1 x 10
< 3 x 10
Warm up (+25 °C): 20 mins to lock

*At temperature 23 °C ± 3 °C

Frequency stability -
Hold-Over

Aging/24h: < 2 x 10
Aging/month: < 5 x 10
Temp. (0 °C to + 50 °C): < 3 x 10
Temp. (23 °C ± 3 °C): < 2 x 10
Short term (Allan dev.):

< 3 x 10
< 1 x 10
< 3 x 10
Warm up (+25 °C): 10 minutes to 4 x 10

Phase noise

Offset Phase noise
1 Hz -80 dBc/Hz (typ.)
10 Hz -90 dBc/Hz (typ.)
100 Hz -130 dBc/Hz (typ.)
1 kHz -140 dBc/Hz (typ.)
10 kHz -140 dBc/Hz (typ.)
100 kHz -145 dBc/Hz (typ.)

*

-12

(τ = 1000 s)

-12

(τ = 100 s)

-11

(τ = 10 s)

-11

(τ = 1 s)

-12

(typ.)

-11

-12

(τ = 100 s)

-11

(τ = 10 s)

-11

(τ = 1 s)

-11

-10

(typ.)

910 (GPS-OCXO)

Frequency stability -
locked to GPS

*Frequency offset (24h mean):

-12

< 2 x 10

Short term (Allan dev.):

< 5 x 10
< 3 x 10
< 5 x 10
< 5 x 10
Warm up (+25 °C): 20 mins to lock

*At temperature 23 °C ± 3 °C

Frequency stability -
Hold-Over

Aging/24h: < 3 x 10
Aging/month: < 3 x 10
Temp. (0 °C to +50 °C): < 2.5 x 10-9

Temp. (23 °C ± 3 °C): < 4 x 10
Short term (Allan dev.):

< 1 x 10
< 5 x 10

-10

< 5 x 10
Warm up (+25 °C): 10 minutes to 5 x 10

Phase noise

Offset Phase noise
1 Hz -100 dBc/Hz (typ.)
10 Hz -120 dBc/Hz (typ.)
100 Hz -130 dBc/Hz (typ.)
1 kHz -135 dBc/Hz (typ.)
10 kHz -135 dBc/Hz (typ.)
100 kHz -135 dBc/Hz (typ.)

-11

(τ = 1000 s)

-11

(τ = 100 s)

-12

(τ = 10 s)

-12

(τ = 1 s)

-10

-9

-11

(τ = 100 s)

-12

(τ = 10 s)

-12

(τ = 1 s)

-10

(typ.)

-9

3 Fluke Calibration 910/910R GPS Controlled Frequency Standards

Common

Reference outputs (BNC)

10 MHz: Sine wave, 0.6 V rms into 50
5 MHz: Sine wave, 0.6 V rms into 50 Ω
1 pps: TTL-levels; low < 0.4 V,

high > 2 V into 50 Ω load.
Pulse output (opt. 75): TTL-levels;
low < 0.4 V, high > 2 V into 50 Ω load

10 MHz and 5 MHz outputs

Freq. stability: See frequency stability
specs for 910 and 910R

1-pps output (locked to GPS)

Duty cycle: Approx. 20 %
Jitter: < 60 ns rms relative to UTC

or GPS (position hold, SA on)

5 additional 10 MHz outputs
(option 70)

See specification for 10 MHz above

Multiple reference outputs
(option 71)

Sine wave outputs: 10, 5, 1 and 0.1
MHz > 1 Vrms into 50 Ω
Pulse output: 0.1 MHz; > 3 Vp-p into 50 Ω
0 V ≤ LO < 0.8 V, 3 V < HI ≤ 5 V

5 additional 2.048 MHz out­puts (option 72)

Frequency: 2.048 MHz square wave
Output level: -1.2 V to +1.2 V

into 75 Ω (G.703:10)
Jitter: < 0.01 UI

5 additional 13 MHz outputs
(option 73)

Output signal: TTL (symmetrical)
Typical levels into 50 Ω:

High voltage: 2.35 V
Low voltage: 0 V

Jitter: < 0.01 UI
Long term stability: Same as main

reference

Pulse output (option 75)

The frequency and duty cycle are set via
the included PC-program

Selectable frequency:

N is an integer

Factory default setting: 1 Hz
Jitter: < 500 ps rms
Freq. stability: See frequency stability

specs for 910 and 910R

Ethernet interface (option 76)

Communication port:
Connector: RJ45
Protocol: 10Base-T
Buffer RAM: 1 kbit
Configuration port:
Connector: Dsub9, RS-232

Internal data storage

24h-freq. offset: two-years data,
non-volatile memory
Adjustment data: two-years data,
non-volatile memory
Phase data (TIE): 40-days data,
volatile memory

4 Fluke Calibration 910/910R GPS Controlled Frequency Standards

N * 1 0

± 10 %

-7

1

Hz;

LED indicators

Locked to GPS, Alarm, Manual Hold-Over

Display indicators

Ω

7-segment area:
24h mean freq. offset (if valid data exist)
Time of day (if GPS gives valid time)
“910” or “910R” (if GPS contact not
sufficient)
Alarm text (plus Alarm LED)
REMOTE segment: Local lock-out
(from PC)
Analog bar graph: Satellite signal
strength

GPS-receiver

Antenna connector: Type N
Channels: 8, parallel tracking
Carrier, code: L1, C/A

Antenna (option 01)

Type: Active L1
Operating temp.: -40 °C to +70 °C
Height: 81 mm (3.2 in) (excl.connector)
Weight: 230 g (8 oz)
Gain: > 30 dB
Connector: TNC

Antenna cable
(option 02/20, option 02/50)

Type: RG213
Length: 20 m (02/20), 50 m (02/50)
Connectors: N-type and TNC (male)
Cable delay: 101 ns (02/20), 251 ns

(02/50)
Attenuation:
Approx. 8 dB at 1.6 GHz (02/20)
Approx. 20 dB at 1.6 GHz (02/50)

PC-connection

Interface: RS-232, DTE

Environmental

Temperature: 0 °C to +50 °C (operating)

-40 °C. to +70 °C (storage)
Safety: Compliant to CE: EN
61010-1 + A1 (1992) + A2 (1995)
EMI: Compliant to CE: EN 61326-1 (1997)

Power consumption

Line voltage: 100 V to 240 V (± 10 %)
Line frequency: 47 Hz to 63 Hz
Power 910R: < 75 W at warm-up

< 35 W continuous operation
Power 910: < 25 W at warm-up
< 12 W continuous operation

Dimensions (WxHxD)

315 mm x 86 mm x 395 mm
(12.4 in x 3.4 in x 15.6 in)

Weight

910R (net) 4.4 kg (9.7 lb)
910R (shipping) 7.4 kg (16.3 lb)
910 (net) 3.9 kg (8.6 lb)
910 (shipping) 6.9 kg (15.2 lb)

Ordering information

910 GPS-Controlled OCXO Frequency Standard. 5 x 10 MHz and 1
x 5 MHz outputs
910R GPS-Controlled Rubidium Frequency Standard. 5 x 10 MHz
and 1 x 5 MHz outputs

910X-70 5 additional 10 MHz outputs
910X-71 Multiple reference outputs – 0.1 MHz, 1 MHz, 5 MHz and

10 MHz sinewave outputs, plus a 0.1 MHz squarewave output

910X-72 5 additional 2.048 MHz outputs
910X-73 5 additional 13 MHz outputs
910X-75 1 additional pulse output 0.5 Hz to 5 MHz
910X-76 Ethernet interface

Included accessories

Operators manual,
GPSView Software

Optional accessories

PM9622/00 Rack Mount Kit
PM9627 Carrying Case
PM9627H Heavy Duty Aluminium Carrying Case
910X-01 GPS Antenna
910X-01/50 GPS Antenna Mounting Kit
910X-02/20 Antenna Cable, 20 m
910X-02/50 Antenna Cable, 50 m
910X-02/130 Antenna cable, 130 m

Fluke Calibration.

Precision, performance, confidence.

Fluke Calibration
PO Box 9090, Everett, WA 98206 U.S.A.

Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands

For more information call:
In the U.S.A. [phone] or
Fax [phone]
In Europe/M-East/Africa [phone] or
Fax [phone]
In Canada (800)-36-FLUKE or
Fax [phone]
From other countries [phone] or
Fax [phone]
Web access: http://www.flukecal.com

©2000-2013 Fluke Calibration.
Specifications subject to change without notice.
Printed in U.S.A. 7/2013 1567182D_EN
Pub_ID: 10780-eng Rev 03

Modification of this document is not permitted
without written permission from Fluke Calibration.

Various options for calibration
certificates are available; contact
your local Fluke Calibration sales

representative for details.

™