amplitude comparison relay
21Digital Radio Mondiale — (abbreviated DRM; mondiale being Italian and French for worldwide ) is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcasting, particularly shortwave. DRM can fit more channels than AM …
22FM broadcasting — See also: frequency modulation and FM broadcast band FM broadcasting is a broadcasting technology pioneered by Edwin Howard Armstrong which uses frequency modulation (FM) to provide high fidelity sound over broadcast radio. The term FM band… …
23Drum — For other uses, see Drum (disambiguation). The drum is a member of the percussion group of musical instruments, which is technically classified as the membranophones.[1] Drums consist of at least one membrane, called a drumhead or drum skin, that …
24Faster-than-light — (also superluminal or FTL) communications and travel refer to the propagation of information or matter faster than the speed of light. Science fiction style space travel, dubbed true FTL, defies known physics.Under the special theory of… …
25Variable-frequency oscillator — A variable frequency oscillator (VFO) in electronics is a oscillator with an oscillation frequency that can be electronically changed (hence, variable).cite book |title=The ARRL Handbook for Radio Amateurs, Sixty Eighth Edition |editor=Larry D.… …
26Mobile phone radiation and health — A man speaking on a mobile telephone The effect of mobile phone radiation on human health is the subject of recent interest and study, as a result of the enormous increase in mobile phone usage throughout the world (as of June 2009 …
27Amateur radio in India — Infobox amateur radio country country=India caption=Amateur radio operators at a foxhunt in Mumbai licensed=16,000 license year=1913 itu region=3 itu zone1=41 itu zone2=49 cq zone1=22 cq zone2=26 itu rep=WPC iaru rep=ARSI callsign1=VUA to VWZ… …
28Multipath propagation — This article is about the electromagnetic propagation phenomenon. For the computing storage term, see Multipath I/O. For the routing term, see Multipath Routing. In wireless telecommunications, multipath is the propagation phenomenon that results …
