Upfade

This term is also used to describe a lighting cue in Stage lighting

Upfade is the term used in radio communications to describe a situation where multipath conditions (in which signals travel from the transmitter to the receiving antenna by two or more paths) cause a radio signal to gain strength.^[1] Some multipath conditions cause a signal's amplitude to be increased in this way because signals travelling by different paths arrive at the receiver in phase and become additive to the main signal. Hence, the total signal that reaches the receiver will be stronger than the signal would otherwise have been without the multipath conditions.

The effect is also noticeable in wireless LAN systems.^[2]

References

1. ↑ Harvey Lehpamer Microwave transmission networks: planning, design, and deployment,McGraw-Hill 2010 ISBN 0-07-170122-2 page 100
2. ↑ Barry D. Lewis, Peter T. Davis Wireless networks for dummies, For Dummies, 2004 ISBN 0-7645-7525-2, page 234