Specifying Rubidium Oscillators

Questions Covered

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What is a rubidium oscillator?

How does a rubidium oscillator work?

Why use a rubidium clock?

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Our IQRB-1 rubidium oscillator is a sub-

miniature atomic clock exhibiting

rubidium oscillator performance in a

65cc OCXO style package at a standard

frequency of 10MHz.

It offers 100 times less drift than an

OCXO and has a short term stability of

0.008ppb/s at 100s, providing

significant improvements in

performance over OCXOs.

What is a rubidium oscillator?

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It is a type of “atomic clock”

These clocks are the most accurate

time standards known and are used as

time distribution services to control

things such as:

telecommunications infrastructure

TV broadcasts

global navigation satellite systems (GPS)

The part of the rubidium oscillator

which is responsible for providing the

output signal is actually a quartz crystal

oscillator (OCXO).

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The rubidium “physics-package” and its

associated control circuitry provides

the timing accuracy to control the

OCXO frequency.

In quartz oscillators, the device is

adjusted to frequency when it is made

but its frequency is never generally

checked again. Over time, its frequency

changes slightly, making the clock run

fast or slow.

The rubidium section of the oscillator

continually checks the frequency of the

quartz oscillator and adjusts it back

onto frequency.

How does a rubidium oscillator work?

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Simplistically, it’s the behaviour and

monitoring of rubidium particles at an

atomic level whereby this behaviour is

subsequently fed electronically to the

control input of a crystal oscillator so

that it’s output frequency can be

adjusted.

Rubidium is usually in the form of a soft

silvery metallic element.

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By using the rubidium as a gas held in a

glass cell and exposing it to light of the

correct frequency, its absorption

changes when the surrounding

microwave frequency is just right.

This absorption rate can be measured

and thus forms the basis of a very stable

clock.

Why use a rubidium clock?

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The advantage of a rubidium clock over

the other atomic devices such as

caesium clocks is that rubidium clocks

are much lower cost, small and portable.

More information can be found on our

website.

Standing out from the crowd

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