[{"n": "Radio electronics", "u": "/e/radio-electronics/radio-electronics/", "s": "Electronic circuits designed to receive or transmit radio signals."}, {"n": "2.4 GHz radio use", "u": "/e/radio-electronics/2-4-ghz-radio-use/", "s": "A shared radio band used by many wireless technologies, prone to interference."}, {"n": "Absorption wavemeter", "u": "/e/radio-electronics/absorption-wavemeter/", "s": "Simple resonant instrument for measuring radio wave frequency."}, {"n": "Alexanderson alternator", "u": "/e/radio-electronics/alexanderson-alternator/", "s": "Rotating machine generating continuous radio waves for longwave communication."}, {"n": "Impedance analyzer", "u": "/e/radio-electronics/impedance-analyzer/", "s": "Measures complex electrical impedance as a function of test frequency."}, {"n": "Antique radio", "u": "/e/radio-electronics/antique-radio/", "s": "Collectible radio receivers valued for age and rarity."}, {"n": "Arc converter", "u": "/e/radio-electronics/arc-converter/", "s": "Early continuous-wave radio transmitter using an electric arc."}, {"n": "Balun", "u": "/e/radio-electronics/balun/", "s": "An electrical device interfacing balanced and unbalanced lines."}, {"n": "Morris Beitman", "u": "/e/radio-electronics/morris-beitman/", "s": "Publisher of condensed radio and television servicing manuals."}, {"n": "Cavity perturbation theory", "u": "/e/radio-electronics/cavity-perturbation-theory/", "s": "Analytical method for resonant frequency and Q factor changes."}, {"n": "Cellular repeater", "u": "/e/radio-electronics/cellular-repeater/", "s": "A bi-directional amplifier that improves cell phone reception indoors or in vehicles."}, {"n": "Coherer", "u": "/e/radio-electronics/coherer/", "s": "Early radio detector using metal filings that cohered under radio signals."}, {"n": "Counterpoise (ground system)", "u": "/e/radio-electronics/counterpoise-ground-system/", "s": "A suspended wire network substituting for an earth ground in antenna systems."}, {"n": "Powel Crosley Jr.", "u": "/e/radio-electronics/powel-crosley-jr/", "s": "Inventor, industrialist, and radio broadcasting pioneer."}, {"n": "Crystal detector", "u": "/e/radio-electronics/crystal-detector/", "s": "Early semiconductor diode used to demodulate radio signals in crystal radios."}, {"n": "Crystal radio", "u": "/e/radio-electronics/crystal-radio/", "s": "A passive radio receiver powered solely by received radio waves."}, {"n": "Diplexer", "u": "/e/radio-electronics/diplexer/", "s": "A passive device that frequency-multiplexes two ports onto one."}, {"n": "Direct-conversion receiver", "u": "/e/radio-electronics/direct-conversion-receiver/", "s": "A single-conversion receiver that demodulates by synchronous detection at the carrier frequency."}, {"n": "Directivity", "u": "/e/radio-electronics/directivity/", "s": "Measure of concentration of radiated power in a single direction."}, {"n": "Distributed-element circuit", "u": "/e/radio-electronics/distributed-element-circuit/", "s": "Circuits using transmission lines to replace lumped components at microwave frequencies."}, {"n": "Edwin Howard Armstrong", "u": "/e/radio-electronics/edwin-howard-armstrong/", "s": "American inventor of FM radio and the superheterodyne receiver."}, {"n": "Dummy load", "u": "/e/radio-electronics/dummy-load/", "s": "A device that simulates an electrical load for testing without radiation or sound."}, {"n": "DYNAS", "u": "/e/radio-electronics/dynas/", "s": "Dynamic analog filtering and tuning for improved FM reception."}, {"n": "Electrolytic detector", "u": "/e/radio-electronics/electrolytic-detector/", "s": "Early rectifying detector used to demodulate AM radio signals."}, {"n": "Electromagnetic shielding", "u": "/e/radio-electronics/electromagnetic-shielding/", "s": "Barriers of conductive or magnetic material reduce or redirect electromagnetic fields."}, {"n": "Federal Telegraph Company", "u": "/e/radio-electronics/federal-telegraph-company/", "s": "Pioneering arc transmitters and early vacuum tube development."}, {"n": "Feed line", "u": "/e/radio-electronics/feed-line/", "s": "The cable connecting antenna to transmitter or receiver."}, {"n": "Frequency mixer", "u": "/e/radio-electronics/frequency-mixer/", "s": "A circuit that produces sum and difference frequencies from two inputs."}, {"n": "Luftwaffe and Kriegsmarine radar equipment of World War II", "u": "/e/radio-electronics/luftwaffe-and-kriegsmarine-radar-equipment-of-world-war-ii/", "s": "German WWII radar directed flak, searchlights, and fighters with increasing sophistication."}, {"n": "Wireless Communications of the German Army in World War II", "u": "/e/radio-electronics/wireless-communications-of-the-german-army-in-world-war-ii/", "s": "German Army FuG radios enabled coordinated armoured and infantry communications."}, {"n": "Ghosting (television)", "u": "/e/radio-electronics/ghosting-television/", "s": "A ghost is a replica of the transmitted image, offset in position."}, {"n": "Gilbert cell", "u": "/e/radio-electronics/gilbert-cell/", "s": "Balanced mixer providing accurate multiplication of differential input currents."}, {"n": "GoTenna", "u": "/e/radio-electronics/gotenna/", "s": "Mesh networking devices for off-grid peer-to-peer communication."}, {"n": "Grid-leak detector", "u": "/e/radio-electronics/grid-leak-detector/", "s": "Demodulates and amplifies AM signals using a vacuum tube."}, {"n": "Hot-wire barretter", "u": "/e/radio-electronics/hot-wire-barretter/", "s": "Early thermoresistive detector for amplitude-modulated signals."}, {"n": "Image response", "u": "/e/radio-electronics/image-response/", "s": "Measure of a superheterodyne receiver's ability to reject the image frequency."}, {"n": "In-phase and quadrature components", "u": "/e/radio-electronics/in-phase-and-quadrature-components/", "s": "Two orthogonal sinusoids that represent amplitude and phase modulation."}, {"n": "Intermediate frequency", "u": "/e/radio-electronics/intermediate-frequency/", "s": "A fixed intermediate frequency enables selective filtering and stable amplification."}, {"n": "Intermodulation", "u": "/e/radio-electronics/intermodulation/", "s": "Unwanted frequency components from nonlinear mixing of multiple signals."}, {"n": "International Radio Corporation", "u": "/e/radio-electronics/international-radio-corporation/", "s": "Pioneering radio manufacturer that created the first AC/DC and clock radios."}, {"n": "IQ imbalance", "u": "/e/radio-electronics/iq-imbalance/", "s": "IQ imbalance corrupts quadrature signals in direct conversion receivers."}, {"n": "Klotz Digital", "u": "/e/radio-electronics/klotz-digital/", "s": "German audio media manufacturer for broadcast and public address."}, {"n": "Lecher line", "u": "/e/radio-electronics/lecher-line/", "s": "Parallel wires used to measure radio wavelength via standing waves."}, {"n": "Load pull", "u": "/e/radio-electronics/load-pull/", "s": "Systematic impedance variation for nonlinear device characterization and design."}, {"n": "Local oscillator", "u": "/e/radio-electronics/local-oscillator/", "s": "Local oscillators enable frequency conversion in superheterodyne receivers and many communications systems."}, {"n": "Logic Trunked Radio", "u": "/e/radio-electronics/logic-trunked-radio/", "s": "Trunked radio system without a dedicated control channel."}, {"n": "Low IF receiver", "u": "/e/radio-electronics/low-if-receiver/", "s": "A receiver topology avoiding DC offset and 1/f noise issues."}, {"n": "Luftwaffe radio equipment of World War II", "u": "/e/radio-electronics/luftwaffe-radio-equipment-of-world-war-ii/", "s": "German Luftwaffe radio, IFF, and RDF equipment of World War II."}, {"n": "Magic eye tube", "u": "/e/radio-electronics/magic-eye-tube/", "s": "A vacuum tube that visually indicates signal strength for tuning."}, {"n": "Magnetic detector", "u": "/e/radio-electronics/magnetic-detector/", "s": "Early radio detector using iron hysteresis to receive Morse code."}, {"n": "Mobile phone signal", "u": "/e/radio-electronics/mobile-phone-signal/", "s": "Signal strength displayed as bars varies with environment and network."}, {"n": "Motorboating (electronics)", "u": "/e/radio-electronics/motorboating-electronics/", "s": "Low-frequency parasitic oscillation causing a pulsing 'put-put-put' sound."}, {"n": "Nanoradio", "u": "/e/radio-electronics/nanoradio/", "s": "A carbon nanotube device that acts as a radio transmitter and receiver."}, {"n": "Network analyzer (electrical)", "u": "/e/radio-electronics/network-analyzer-electrical/", "s": "Measures network parameters, commonly s-parameters, for electrical networks."}, {"n": "Neutrodyne", "u": "/e/radio-electronics/neutrodyne/", "s": "A TRF receiver that neutralized tube capacitance to stop howling."}, {"n": "Noise blanker", "u": "/e/radio-electronics/noise-blanker/", "s": "A circuit that reduces impulse noise in radio receivers."}, {"n": "Nyquist filter", "u": "/e/radio-electronics/nyquist-filter/", "s": "A receiver filter that equalizes video after VSB transmission."}, {"n": "Orthomode transducer", "u": "/e/radio-electronics/orthomode-transducer/", "s": "Waveguide component that separates or combines orthogonal microwave polarizations."}, {"n": "Phase-locked loop", "u": "/e/radio-electronics/phase-locked-loop/", "s": "A control system that locks output phase to input phase."}, {"n": "Phase-locked loop range", "u": "/e/radio-electronics/phase-locked-loop-range/", "s": "Frequency deviation intervals for PLL lock under varying conditions."}, {"n": "Plasma antenna", "u": "/e/radio-electronics/plasma-antenna/", "s": "Plasma replaces metal in antennas for stealth and reconfigurability."}, {"n": "PLL multibit", "u": "/e/radio-electronics/pll-multibit/", "s": "Multibit PLL improves performance by using more counter bits."}, {"n": "Power dividers and directional couplers", "u": "/e/radio-electronics/power-dividers-and-directional-couplers/", "s": "Passive devices that couple defined electromagnetic power between transmission line ports."}, {"n": "Predistortion", "u": "/e/radio-electronics/predistortion/", "s": "Predistortion improves amplifier linearity by cancelling non-linear distortion."}, {"n": "Preselector", "u": "/e/radio-electronics/preselector/", "s": "An adjustable band-pass filter that reduces interference before the receiver."}, {"n": "Q meter", "u": "/e/radio-electronics/q-meter/", "s": "Measures the quality factor of radio frequency circuits."}, {"n": "Q multiplier", "u": "/e/radio-electronics/q-multiplier/", "s": "A regenerative circuit that sharpens receiver selectivity via positive feedback."}, {"n": "Quasi-peak detector", "u": "/e/radio-electronics/quasi-peak-detector/", "s": "A detector with defined dynamics used in EMC and audio measurement."}, {"n": "Radiation efficiency", "u": "/e/radio-electronics/radiation-efficiency/", "s": "Ratio of radiated power to accepted power, frequency dependent."}, {"n": "Radio hat", "u": "/e/radio-electronics/radio-hat/", "s": "A pith helmet with a built-in AM radio, sold from coast to coast."}, {"n": "Radio receiver design", "u": "/e/radio-electronics/radio-receiver-design/", "s": "Design of receivers balancing gain, selectivity, sensitivity, and stability."}, {"n": "Radio repeater", "u": "/e/radio-electronics/radio-repeater/", "s": "A radio relay station that extends communication range over obstacles."}, {"n": "Radio spectrum scope", "u": "/e/radio-electronics/radio-spectrum-scope/", "s": "Measures signal magnitude versus frequency across radio bands."}, {"n": "Radio transmitter design", "u": "/e/radio-electronics/radio-transmitter-design/", "s": "Design of circuits that generate and modulate radio waves for communication."}, {"n": "Radio-frequency induction", "u": "/e/radio-electronics/radio-frequency-induction/", "s": "Energy transfer via radio frequency magnetic field in the near field."}, {"n": "Radiogram (device)", "u": "/e/radio-electronics/radiogram-device/", "s": "Furniture combining radio and record player, popular post-war."}, {"n": "Reflex receiver", "u": "/e/radio-electronics/reflex-receiver/", "s": "A single amplifier amplifies both RF and audio signals."}, {"n": "Regenerative circuit", "u": "/e/radio-electronics/regenerative-circuit/", "s": "Positive feedback amplifier circuit used to greatly increase gain."}, {"n": "Repeater", "u": "/e/radio-electronics/repeater/", "s": "A device that receives and retransmits a signal to extend range."}, {"n": "Return loss", "u": "/e/radio-electronics/return-loss/", "s": "Return loss quantifies signal reflection at impedance mismatches."}, {"n": "RF chain", "u": "/e/radio-electronics/rf-chain/", "s": "Cascade of RF components for signal processing from 100 kHz to 20 GHz."}, {"n": "RF front end", "u": "/e/radio-electronics/rf-front-end/", "s": "Circuitry between antenna and mixer in a superheterodyne receiver."}, {"n": "RF power amplifier", "u": "/e/radio-electronics/rf-power-amplifier/", "s": "Converts low-power RF signals into higher-power signals for transmission."}, {"n": "RF probe", "u": "/e/radio-electronics/rf-probe/", "s": "Device for measuring RF signals in electronic circuits."}, {"n": "Rolling code", "u": "/e/radio-electronics/rolling-code/", "s": "A rolling code changes each use to thwart replay attacks."}, {"n": "Roofing filter", "u": "/e/radio-electronics/roofing-filter/", "s": "Limits early IF passband to prevent overload distortion."}, {"n": "Short-range device", "u": "/e/radio-electronics/short-range-device/", "s": "License-free low-power transmitters for short-range wireless communication."}, {"n": "Signal reflection", "u": "/e/radio-electronics/signal-reflection/", "s": "Impedance mismatches cause signal echoes that degrade transmission quality."}, {"n": "Slotted line", "u": "/e/radio-electronics/slotted-line/", "s": "A precision transmission line with a movable probe for microwave measurements."}, {"n": "Spark-gap transmitter", "u": "/e/radio-electronics/spark-gap-transmitter/", "s": "The first type of radio transmitter, using electric sparks to generate waves."}, {"n": "Spiral antenna", "u": "/e/radio-electronics/spiral-antenna/", "s": "Spiral antennas provide broadband, circularly polarized performance in a compact form."}, {"n": "Squelch", "u": "/e/radio-electronics/squelch/", "s": "Squelch suppresses receiver output when no signal is present."}, {"n": "Standing wave ratio", "u": "/e/radio-electronics/standing-wave-ratio/", "s": "SWR measures impedance matching via standing wave amplitude ratio."}, {"n": "Stub (electronics)", "u": "/e/radio-electronics/stub-electronics/", "s": "A transmission line stub provides reactive impedance for RF circuits."}, {"n": "Harmonic mixer", "u": "/e/radio-electronics/harmonic-mixer/", "s": "A mixer using harmonic multiples to simplify high-frequency signal conversion."}]