Quantized radio modulation modes: Pulse-amplitude modulation, Phase-shift keying, Orthogonal frequency-division multiplexing

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 62. Chapters: Pulse-amplitude modulation, Phase-shift keying, Orthogonal frequency-division multiplexing, Frequency-shift keying, Radioteletype, Direct-sequence spread spectrum, Frequency-hopping spread spectrum, Automatic link establishment, Isochronous burst transmission, Pulse-position modulation, D-STAR, Pulse-code modulation, Olivia MFSK, WSJT, MT63, MDC-1200, PSK31, Amplitude-shift keying, Multiple frequency-shift keying, Hellschreiber, Binary offset carrier, SITOR, Very minimum-shift keying, PACTOR, Complementary code keying, Cyclic prefix, Constellation diagram, WSPR, Link adaptation, Guard interval, Error vector magnitude, Hierarchical modulation, PSK63, AMTOR, MPH, Modulation error ratio, Q15X25, XMax, Gaussian frequency-shift keying, Amplitude and phase-shift keying, On-off keying, CLOVER2000, MBOC, Wavelet modulation, TC-PAM, M-ary transmission, Higher-order modulation. Excerpt: Orthogonal frequency-division multiplexing (OFDM), essentially identical to coded OFDM (COFDM) and discrete multi-tone modulation (DMT), is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. A large number of closely-spaced orthogonal sub-carriers are used to carry data. The data is divided into several parallel data streams or channels, one for each sub-carrier. Each sub-carrier is modulated with a conventional modulation scheme (such as quadrature amplitude modulation or phase-shift keying) at a low symbol rate, maintaining total data rates similar to conventional single-carrier modulation schemes in the same bandwidth. OFDM has developed into a popular scheme for wideband digital communication, whether wireless or over copper wires, used in applications such as digital television and audio broadcasting, wireless networking and broadband internet access. The primary advantage of OFDM over single...