Radio Modulation Modes, Part 2
36 entries in the Radio Modulation Modes, Part 2 compendium.
ARQ-EA synchronous shortwave data system with automatic error correction.ARQ-MA duplex radio protocol for reliable telex over shortwave.Automatic link establishmentDigital standard for automatic HF radio linking and channel selection.Binary offset carrier modulationA split-spectrum modulation enabling satellite navigation system interoperability.CLOVER2000Higher-rate HF waveform developed in 1995.Complementary code keyingA modulation scheme for 802.11b at 5.5 and 11 Mbit/s.Constellation diagramA scatter diagram of digital modulation symbols in the complex plane.Constellation shapingModifies symbol probabilities to improve energy efficiency in digital modulation.Cyclic prefixPrefixing a symbol with its end to combat multipath interference.D-STARFirst digital voice protocol designed specifically for amateur radio.Direct-sequence spread spectrumSpreads signal bandwidth to reduce interference and enable multiple access.Error vector magnitudeA measure of deviation from ideal constellation points.FldigiFree sound-card modem software for amateur radio worldwide.Frequency-hopping spread spectrumA method of rapidly switching carrier frequencies to resist interference and eavesdropping.FT8A weak-signal digital mode for amateur radio using 15-second cycles.HellschreiberA facsimile teleprinter providing intelligible communication over poor links.Hierarchical modulationLayered modulation for graceful signal degradation in digital TV.Link adaptationDynamic matching of modulation and coding to radio link conditions.MDC-1200Motorola's 1,200 baud AFSK data system for two-way radio.Minimum-shift keyingA constant-envelope digital modulation with half-bit-rate frequency separation.Modulation error ratioA measure of digital modulation signal quality from ideal constellation points.MT63Robust digital mode for high-noise HF keyboard conversations.Multiple frequency-shift keyingMFSK uses multiple tones to transmit data with constant envelope.Non-orthogonal frequency-division multiplexingA multi-carrier modulation method using non-orthogonal subcarrier spacing.Olivia MFSKA robust amateur MFSK protocol for weak-signal shortwave communication.Orthogonal frequency-division multiple accessMulti-user OFDM variant assigning subcarriers to individual users.Orthogonal frequency-division multiplexingA digital modulation scheme using multiple orthogonal subcarriers.PACTORA digital mode combining AMTOR and packet radio for HF data transfer.Phase-shift keyingDigital modulation that encodes data by varying carrier phase.PSK31A narrowband digital mode for keyboard-to-keyboard amateur radio chat.Pulse-amplitude modulationPAM encodes message information in pulse amplitude.Pulse-frequency modulationA modulation method encoding analog signals by varying pulse frequency.Pulse-position modulationPPM encodes data via pulse timing, used in optical and RC systems.RadioteletypeRadioteletype connects teleprinters over radio using FSK or AFSK modulation.SITORA teletype system using error correction for reliable maritime and amateur radio text.Very minimum shift keyingUltra-narrow-band modulation method with disputed spectral efficiency claims.
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