Atec Fluke-910-910R User Manual

Page 2

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 col-

lection, 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

to monitor both instrument and

GPS status, or even collect cali-

bration data, via the internet or

any Local Area Network.

With Ethernet interface con-

nectivity, distances to which

data can be transmitted become

unlimited, unlike that of any

standard GPIB or RS-232 inter-

terface, thereby allowing the

910/910R to be monitored from

practically anywhere.

This means that the metro-

logist 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 simultane-

ously viewed in real time.
Two high-stability operating

modes to suit your application

Most users prefer automatic

adjustment (known as disciplin-

ing) 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-to-

medium term stability of all local

oscillators, except rubidium, is

compromised. This is true for all

GPS frequency references. The

received GPS signal has rela-

tively large short-term frequency

variations, due to variations in

atmospheric conditions. This

means that when using the

received GPS signal for disciplin-

ing 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 inter-

nal timebase oscillator and the

received GPS-signal is used to

continuously adjust the oscillator

(disciplining). The resulting fre-

quency offset and adjustment data

is stored in non-volatile memory

every 24-hours, to enable print-

out 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 mea-

surement and a superior stability

through the measurement.

Here, the internal oscilla-

tor is not adjusted. This mode is

normally automatically entered

when there is no usable received

GPS-signal. This mode can also

GPS-

Receiver

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

2 Fluke Calibration 910/910R GPS Controlled Frequency Standards