Link Budget
A tabulated accounting of all gains and losses in a satellite communications path, from transmitter to receiver, used to determine whether a signal can be reliably received. The final result is typically expressed as link margin.
Full Definition
A link budget is a systematic calculation that tracks signal power as it travels from a source transmitter through free space and atmospheric effects to a destination receiver, listing every gain and loss along the path. Key inputs include EIRP, free-space path loss, atmospheric attenuation, G/T, and required Eb/N0 or C/N. The output—link margin—indicates how much headroom exists above the minimum acceptable threshold. Editors working on link budget documents must ensure consistent units (typically dBW or dBm) throughout all tables and that all parameters are defined at the same reference frequency and polarisation. The term is written as two words, unhyphenated, in most technical style guides.
Usage
Usage note: Two words, no hyphen: 'link budget'. Do not capitalise unless part of a proper document title. Distinguish clearly from 'link margin', which is the output of the link budget calculation.
In Context
- "The link budget confirmed a 3.2 dB margin under the worst-case rain-fade scenario at Ku-band." — System Design Document
- "Editors should flag any link budget table in which gains and losses are not expressed in a consistent unit system." — Editorial Style Guide