[{"n": "Signal modulation", "u": "/e/radio-modulation-modes/signal-modulation/", "s": "Modulation varies a carrier wave to transmit information."}, {"n": "Ampliphase", "u": "/e/radio-modulation-modes/ampliphase/", "s": "Ampliphase: amplitude modulation via summing phase-modulated carriers."}, {"n": "Amplitude-companded single-sideband modulation", "u": "/e/radio-modulation-modes/amplitude-companded-single-sideband-modulation/", "s": "Narrowband modulation using companding and a pilot tone for improved range."}, {"n": "Armstrong phase modulator", "u": "/e/radio-modulation-modes/armstrong-phase-modulator/", "s": "Armstrong's 1933 method generated FM via phase-shifted double sideband suppressed carrier."}, {"n": "Beacon mode service", "u": "/e/radio-modulation-modes/beacon-mode-service/", "s": "CCSDS beacon mode relays spacecraft health via simple tones."}, {"n": "Carrierless amplitude phase modulation", "u": "/e/radio-modulation-modes/carrierless-amplitude-phase-modulation/", "s": "A QAM variant that avoids explicit carrier modulation."}, {"n": "Damped wave (radio transmission)", "u": "/e/radio-modulation-modes/damped-wave-radio-transmission/", "s": "Early radio transmission method using damped waves."}, {"n": "Double-sideband suppressed-carrier transmission", "u": "/e/radio-modulation-modes/double-sideband-suppressed-carrier-transmission/", "s": "DSB-SC transmits both sidebands but suppresses the carrier for efficiency."}, {"n": "E-VSB", "u": "/e/radio-modulation-modes/e-vsb/", "s": "Optional ATSC enhancement for weaker signal reception and mobile devices."}, {"n": "Envelope (waves)", "u": "/e/radio-modulation-modes/envelope-waves/", "s": "Smooth curve outlining the extremes of an oscillating signal."}, {"n": "Frequency modulation", "u": "/e/radio-modulation-modes/frequency-modulation/", "s": "Frequency modulation varies carrier frequency with message signal amplitude."}, {"n": "Keying (telecommunications)", "u": "/e/radio-modulation-modes/keying-telecommunications/", "s": "Digital modulation for transmitting digital signals over analog channels."}, {"n": "Modulated continuous wave", "u": "/e/radio-modulation-modes/modulated-continuous-wave/", "s": "Morse code telegraphy using an audio tone to modulate a carrier wave."}, {"n": "Phase-fired controller", "u": "/e/radio-modulation-modes/phase-fired-controller/", "s": "A method for power limiting by phase-angle switching of AC waveforms."}, {"n": "Phase modulation", "u": "/e/radio-modulation-modes/phase-modulation/", "s": "Angle modulation encoding message signal as carrier phase variations."}, {"n": "Polar modulation", "u": "/e/radio-modulation-modes/polar-modulation/", "s": "Polar modulation uses amplitude and phase to enable non-linear amplifiers."}, {"n": "Quadrature amplitude modulation", "u": "/e/radio-modulation-modes/quadrature-amplitude-modulation/", "s": "A family of modulation methods conveying two signals on orthogonal carriers."}, {"n": "Reduced-carrier transmission", "u": "/e/radio-modulation-modes/reduced-carrier-transmission/", "s": "AM transmission reducing carrier level to save power and boost sidebands."}, {"n": "Ring modulation", "u": "/e/radio-modulation-modes/ring-modulation/", "s": "Ring modulation multiplies two signals, outputting sum and difference frequencies."}, {"n": "Single-sideband modulation", "u": "/e/radio-modulation-modes/single-sideband-modulation/", "s": "A bandwidth- and power-efficient refinement of amplitude modulation."}, {"n": "Types of radio emissions", "u": "/e/radio-modulation-modes/types-of-radio-emissions/", "s": "ITU system for classifying radio emissions by signal characteristics."}, {"n": "Demodulation", "u": "/e/radio-modulation-modes/demodulation/", "s": "Demodulation recovers original information from a modulated carrier wave."}, {"n": "Detector (radio)", "u": "/e/radio-modulation-modes/detector-radio/", "s": "A circuit that extracts information from a modulated radio signal."}, {"n": "Envelope detector", "u": "/e/radio-modulation-modes/envelope-detector/", "s": "Circuit that extracts the envelope of a high-frequency signal."}, {"n": "Foster–Seeley discriminator", "u": "/e/radio-modulation-modes/foster-seeley-discriminator/", "s": "FM detector using a tuned transformer and rectifier diodes."}, {"n": "Product detector", "u": "/e/radio-modulation-modes/product-detector/", "s": "A demodulator that multiplies signal with a local oscillator."}, {"n": "Amplitude and phase-shift keying", "u": "/e/radio-modulation-modes/amplitude-and-phase-shift-keying/", "s": "APSK combines amplitude and phase modulation for lower error rates."}, {"n": "Amplitude-shift keying", "u": "/e/radio-modulation-modes/amplitude-shift-keying/", "s": "Digital data encoded as carrier amplitude variations."}, {"n": "ARQ-E", "u": "/e/radio-modulation-modes/arq-e/", "s": "A synchronous shortwave data system with automatic error correction."}, {"n": "ARQ-M", "u": "/e/radio-modulation-modes/arq-m/", "s": "A duplex radio protocol for reliable telex over shortwave."}, {"n": "Automatic link establishment", "u": "/e/radio-modulation-modes/automatic-link-establishment/", "s": "Digital standard for automatic HF radio linking and channel selection."}, {"n": "Binary offset carrier modulation", "u": "/e/radio-modulation-modes/binary-offset-carrier-modulation/", "s": "A split-spectrum modulation enabling satellite navigation system interoperability."}, {"n": "CLOVER2000", "u": "/e/radio-modulation-modes/clover2000/", "s": "Higher-rate HF waveform developed in 1995."}, {"n": "Complementary code keying", "u": "/e/radio-modulation-modes/complementary-code-keying/", "s": "A modulation scheme for 802.11b at 5.5 and 11 Mbit/s."}, {"n": "Constellation diagram", "u": "/e/radio-modulation-modes/constellation-diagram/", "s": "A scatter diagram of digital modulation symbols in the complex plane."}, {"n": "Constellation shaping", "u": "/e/radio-modulation-modes/constellation-shaping/", "s": "Modifies symbol probabilities to improve energy efficiency in digital modulation."}, {"n": "Cyclic prefix", "u": "/e/radio-modulation-modes/cyclic-prefix/", "s": "Prefixing a symbol with its end to combat multipath interference."}, {"n": "D-STAR", "u": "/e/radio-modulation-modes/d-star/", "s": "First digital voice protocol designed specifically for amateur radio."}, {"n": "Direct-sequence spread spectrum", "u": "/e/radio-modulation-modes/direct-sequence-spread-spectrum/", "s": "Spreads signal bandwidth to reduce interference and enable multiple access."}, {"n": "Error vector magnitude", "u": "/e/radio-modulation-modes/error-vector-magnitude/", "s": "A measure of deviation from ideal constellation points."}, {"n": "Fldigi", "u": "/e/radio-modulation-modes/fldigi/", "s": "Free sound-card modem software for amateur radio worldwide."}, {"n": "Frequency-hopping spread spectrum", "u": "/e/radio-modulation-modes/frequency-hopping-spread-spectrum/", "s": "A method of rapidly switching carrier frequencies to resist interference and eavesdropping."}, {"n": "FT8", "u": "/e/radio-modulation-modes/ft8/", "s": "A weak-signal digital mode for amateur radio using 15-second cycles."}, {"n": "Hellschreiber", "u": "/e/radio-modulation-modes/hellschreiber/", "s": "A facsimile teleprinter providing intelligible communication over poor links."}, {"n": "Hierarchical modulation", "u": "/e/radio-modulation-modes/hierarchical-modulation/", "s": "Layered modulation for graceful signal degradation in digital TV."}, {"n": "Link adaptation", "u": "/e/radio-modulation-modes/link-adaptation/", "s": "Dynamic matching of modulation and coding to radio link conditions."}, {"n": "MDC-1200", "u": "/e/radio-modulation-modes/mdc-1200/", "s": "Motorola's 1,200 baud AFSK data system for two-way radio."}, {"n": "Minimum-shift keying", "u": "/e/radio-modulation-modes/minimum-shift-keying/", "s": "A constant-envelope digital modulation with half-bit-rate frequency separation."}, {"n": "Modulation error ratio", "u": "/e/radio-modulation-modes/modulation-error-ratio/", "s": "A measure of digital modulation signal quality from ideal constellation points."}, {"n": "MT63", "u": "/e/radio-modulation-modes/mt63/", "s": "Robust digital mode for high-noise HF keyboard conversations."}, {"n": "Multiple frequency-shift keying", "u": "/e/radio-modulation-modes/multiple-frequency-shift-keying/", "s": "MFSK uses multiple tones to transmit data with constant envelope."}, {"n": "Non-orthogonal frequency-division multiplexing", "u": "/e/radio-modulation-modes/non-orthogonal-frequency-division-multiplexing/", "s": "A multi-carrier modulation method using non-orthogonal subcarrier spacing."}, {"n": "Olivia MFSK", "u": "/e/radio-modulation-modes/olivia-mfsk/", "s": "A robust amateur MFSK protocol for weak-signal shortwave communication."}, {"n": "Orthogonal frequency-division multiple access", "u": "/e/radio-modulation-modes/orthogonal-frequency-division-multiple-access/", "s": "Multi-user OFDM variant assigning subcarriers to individual users."}, {"n": "Orthogonal frequency-division multiplexing", "u": "/e/radio-modulation-modes/orthogonal-frequency-division-multiplexing/", "s": "A digital modulation scheme using multiple orthogonal subcarriers."}, {"n": "PACTOR", "u": "/e/radio-modulation-modes/pactor/", "s": "A digital mode combining AMTOR and packet radio for HF data transfer."}, {"n": "Phase-shift keying", "u": "/e/radio-modulation-modes/phase-shift-keying/", "s": "Digital modulation that encodes data by varying carrier phase."}, {"n": "PSK31", "u": "/e/radio-modulation-modes/psk31/", "s": "A narrowband digital mode for keyboard-to-keyboard amateur radio chat."}, {"n": "Pulse-amplitude modulation", "u": "/e/radio-modulation-modes/pulse-amplitude-modulation/", "s": "PAM encodes message information in pulse amplitude."}, {"n": "Pulse-frequency modulation", "u": "/e/radio-modulation-modes/pulse-frequency-modulation/", "s": "A modulation method encoding analog signals by varying pulse frequency."}, {"n": "Pulse-position modulation", "u": "/e/radio-modulation-modes/pulse-position-modulation/", "s": "PPM encodes data via pulse timing, used in optical and RC systems."}, {"n": "Radioteletype", "u": "/e/radio-modulation-modes/radioteletype/", "s": "Radioteletype connects teleprinters over radio using FSK or AFSK modulation."}, {"n": "SITOR", "u": "/e/radio-modulation-modes/sitor/", "s": "A teletype system using error correction for reliable maritime and amateur radio text."}, {"n": "Very minimum shift keying", "u": "/e/radio-modulation-modes/very-minimum-shift-keying/", "s": "Ultra-narrow-band modulation method with disputed spectral efficiency claims."}, {"n": "WSJT (amateur radio software)", "u": "/e/radio-modulation-modes/wsjt-amateur-radio-software/", "s": "Weak-signal amateur radio software for exotic propagation modes."}, {"n": "WSPR (amateur radio software)", "u": "/e/radio-modulation-modes/wspr-amateur-radio-software/", "s": "Weak-signal propagation testing protocol for amateur radio."}, {"n": "Software-defined radio", "u": "/e/radio-modulation-modes/software-defined-radio/", "s": "Radio communication system implemented via software on general-purpose hardware."}, {"n": "2G", "u": "/e/radio-modulation-modes/2g/", "s": "Digital cellular network that enabled encrypted voice and SMS."}, {"n": "3G adoption", "u": "/e/radio-modulation-modes/3g-adoption/", "s": "3G adoption was delayed by high costs and infrastructure needs."}, {"n": "4G", "u": "/e/radio-modulation-modes/4g/", "s": "All-IP packet-switched cellular generation with gigabit-speed capability."}, {"n": "Artemis Networks", "u": "/e/radio-modulation-modes/artemis-networks/", "s": "Software-defined radio creating individual virtual cells for each user."}, {"n": "DECT", "u": "/e/radio-modulation-modes/dect/", "s": "ETSI cordless telephony standard, evolved for IoT and 5G."}, {"n": "DECT-2020", "u": "/e/radio-modulation-modes/dect-2020/", "s": "ETSI 5G-compliant radio standard for DECT bands."}, {"n": "E-LynX", "u": "/e/radio-modulation-modes/e-lynx/", "s": "Digital military SDR family for simultaneous voice, data, and video."}, {"n": "Electra (radio)", "u": "/e/radio-modulation-modes/electra-radio/", "s": "A UHF relay payload for Mars communications and navigation."}, {"n": "Frontier Radio", "u": "/e/radio-modulation-modes/frontier-radio/", "s": "Family of software-defined radios from APL for near and deep space."}, {"n": "GNSS software-defined receiver", "u": "/e/radio-modulation-modes/gnss-software-defined-receiver/", "s": "A GNSS receiver implemented via software-defined radio on a general-purpose processor."}, {"n": "GNU Radio", "u": "/e/radio-modulation-modes/gnu-radio/", "s": "Free software toolkit for software-defined radio and signal processing."}, {"n": "HackRF One", "u": "/e/radio-modulation-modes/hackrf-one/", "s": "Open source SDR transceiver for 1 MHz to 6 GHz."}, {"n": "OpenHPSDR", "u": "/e/radio-modulation-modes/openhpsdr/", "s": "Modular open-source SDR project enabling experimentation with new radio techniques."}, {"n": "SpeakEasy", "u": "/e/radio-modulation-modes/speakeasy/", "s": "First large-scale software radio for military interoperability."}, {"n": "Wireless Innovation Forum", "u": "/e/radio-modulation-modes/wireless-innovation-forum/", "s": "A non-profit advancing spectrum innovation and critical communications technologies."}]