NPL research helps drive forward the creation of a Digital Britain

But with increased data comes the potential for increased frequency interference. This could mean data files and live "on-demand" TV services will be corrupted.

If the scientists at the National Physical Laboratory (NPL) have their way, however, the development of more accurate frequency standards technology will mean that this doesn't have to be the case.

Under a European Metrology Research Programme (EMRP) jointly supported by the European Commission and the European Association of National Metrology Institutes (EURAMET), a research team at NPL's laboratories in Teddington is planning to develop more accurate frequency standards technology.

Mixed Signals

Currently, data transmitted through optical fibres is sent down one of a number of internationally agreed channels operating at very specific optical frequencies.

Data providers need to make sure they adhere to these frequencies so that their transmitters never drift close to neighbouring channels, which could cause interference and crosstalk.

To check the long-term performance of these transmitters, manufacturers have to periodically calibrate these sources using frequency standard equipment.

But the relentless increase in data traffic is likely to lead to channel spacings moving closer together, increasing the demand for more accurate, on-site frequency standards technology.

Frequency Standards

Frequency standard systems that are accurate enough for industrial applications have already been developed at the NPL laboratories, but these instruments are generally too complex to be deployed in the field.

The problem is that the higher accuracy frequency standards are usually bulky and need to be operated by trained personnel. They are also not designed for extended operation in demanding industrial environments where there are often high levels of temperature fluctuations and vibration.

But if the user transmitter frequencies are going to be tested on-site at a manufacturer's premises, then the next generation of frequency standard technology needs to be able to operate in industrial environments.

The European Metrology Research Programme (EMRP)

The development of "user friendly" frequency stabilised laser sources is proposed over the next three years in a European Metrology Research Programme (EMRP) project which is being coordinated by NPL.

'We envisage an opto-electronic system within a 19 inch rack that provides an on-site frequency calibration service,' said Geoffrey Barwood, lead researcher on the project. 'We hope the system will be a turnkey standard for companies to use. If we do want to move to a Digital Britain this type of equipment becomes an essential part of the infrastructure.'

As well as NPL, this collaboration includes Spain, Denmark, Switzerland, Italy, France, Finland and Germany. The success of the project proposal was, in part, due to the large number of letters of support received from various European companies, government agencies and standards committees emphasising the need for this equipment.

'The project is not only vital for the telecommunications and broadcast industries, but also for calibrating frequencies in areas such as aerospace, defence, instrument manufacture, gas sensing, and navigation,' said Barwood.

Provided by National Physical Laboratory