Glossary: F


A teletext enhancement that automatically stores specific pages in a memory for quick access via coloured-coded buttons on the TV handset.


Forward Error Correction

A technique for improving the robustness of data transmission. Excess bits are included in the outgoing data stream so that error-correction algorithms can be applied upon reception. For the satellite standard the Viterbi code combined with the Reed Solomon code is used. Commercial use of transponders makes 3/4 the code rate most used for Viterbi, which means that three out of four bits contain useable information.

Flicker-free TV

Flicker-free or 100Hz televisions improve picture quality by doubling the normal scanning rate of a TV from 50 to 100Hz to reduce picture flicker.


Geographic area covered by a satellite transmission.

Forward path

The transmission path issued from the service provider and reaching the end user.

Free to air

Services that are free to everyone, with no need for a special decoder to receive them.


A free-to-air digital satellite service from the BBC and ITV offering over 130 TV and radio stations.


A national free-to-air digital terrestrial service offering over 70 TV and radio channels.

Frequency spectrum

A range of frequencies.


Flat square tube

A CRT TV tube that improves picture quality by having a flatter, less rounded surface and squarer corners than conventional CRT tubes: rapidly being replaced by flat-panel technologies.