Radio: Béda antarrépisi

[[FM broadcasting|Radio siaran FM]] ngirimkeun musik jeung ucapan kalayan ''kehandalan'' (''fidelity'') anu leuwih hadé tibatan radio AM. Dina [[modulasi frékuénsi]], parobahan amplitudo dina [[mikropon]] nyababkeun frékuénsi ''transmitter'' fluktuasi. Lantaran sinyal audio ngamodulasi frékuénsi lain amplitudo, mangka sinyal FM henteu keuna ku gangguan statik sarta interférensi saperti halna sinyal AM. FM dipancarkeun dina spéktrum gelombang radio Frékuénsi Luhur Pisan atawa ''Very High Frequency'' (VHF—30 MHz nepi ka 300 MHz). <!-- FM merlukeun spéktrum frekuensi radio leuwih loba batan AM sedengkeun hal ieu bisa dicumponan dina frékuénsi luhur. Akibatna, dina siaran FM bisa aya leuwih loba stasiun, anu masing-masingna ngirim informasi leuwih loba. --> Gelombang radio VHF watekna leuwih mirupa cahaya, ngarambat dina garis anu lempeng, sahingga jarak panarimaan kawates antara 50-100 mil. Dina kondisi atmosfir bagian luhur anu henteu biasa, sinyal FM kadang dipantulkeun balik ka bumi ku [[ionosfir]], ngakibatkeun [[TV/FM DX|jarak pancar FM anu jauh]]. ''Receiver'' FM keuna ku [[capture effect]], anu nyababkeun radio ngan narima sinyal anu paling kuat mangsa aya leuwih ti hiji sinyal anu datang dina frékuénsi nu sarua. ''Receiver'' FM relatif kebal tina gangguan kilat jeung interférensi.

 

 

 

FM Sub-carrier services are secondary signals transmitted "[[piggyback]]" along with the main program. Special receivers are required to utilize these services. Analog channels may contain alternative programming, such as reading services for the blind, background music or stereo sound signals. In some extremely crowded metropolitan areas, the sub-channel program might be an alternate foreign language radio program for various ethnic groups. Sub-carriers can also transmit digital data, such as station identification, the current song's name, web addresses, or stock quotes. In some countries, FM radios automatically re-tune themselves to the same channel in a different district by using sub-bands.