Radio: Béda antarrépisi

Sanajan panimuan radio lila dikaitkeun jeung [[Guglielmo Marconi]], jatidiri [[invention of radio|panimu radio]] anu mimiti, anu dina mangsa harita disebut [[wireless telegraphy]], jadi bahan kontrovérsi [http://www.gutenberg.org/files/15207/15207-8.txt]. Kamajuan ti mimiti percobaan di laboratorium nepi ka radio jadi barang kaperluan komérsial ngabutuhkeun waktu sabababaraha dasawarsa sarta merlukeun usaha ti para panalitipanalungtik. Kontrovérsi ngeunaan saha anu nimukeun radio, bisa kapanggih ku cara merhatikeun kronologi ditimukeunna radio saperti di handap ieu:

Systems that need reliability, or that share their frequency with other services, may use "coded orthogonal frequency-division multiplexing" or [[COFDM]]. COFDM bréaks a digital signal into as many as several hundred slower subchannels. The digital signal is often sent as QAM on the subchannels. Modernmodérn COFDM systems use a small computer to maké and decode the signal with [[digital signal processing]], which is more flexible and far less expensive than older systems that implemented separate electronic channels. COFDM resists fading and ghosting because the narrow-channel QAM signals can be sent slowly. An adaptive system, or one that sends error-correction codes can also resist interference, because most interference can affect only a few of the QAM channels. COFDM is used for [[WiFi]], some [[cell phone]]s, [[Digital Radio Mondiale]], [[Eureka 147]], and many other local aréa network, digital TV and radio standards.