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Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave.In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to that of the message signal, such as an audio signal.
Most amateur digital modes are transmitted by inserting audio into the microphone input of a radio and using an analog scheme, such as amplitude modulation (AM), frequency modulation (FM), or single-sideband modulation (SSB). Amateur teleprinting over radio (AMTOR) D-STAR (Digital Data) a high speed (128 kbit/s), data-only mode.
Frequency deviation is used in FM radio to describe the difference between the minimum or maximum extent of a frequency modulated signal, and the nominal center or carrier frequency. The term is sometimes mistakenly used as synonymous with frequency drift , which is an unintended offset of an oscillator from its nominal frequency.
The FM modulation and demodulation process is identical in stereo and monaural processes. FM is commonly used at VHF radio frequencies for high-fidelity broadcasts of music and speech. In broadcast services, where audio fidelity is important, wideband FM is generally used. Analog TV sound is also broadcast using FM.
PEP is also equal to average power in a steady FM, FSK, or RTTY transmission. Although average power is the same as PEP for complex modulation forms, such as FSK , the peak envelope power bears no particular ratio or mathematical relationship to longer-term average power in distorted envelopes, such as a CW waveform with power overshoot, or ...
AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmissions, but also on the longwave and shortwave radio bands.
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Wide FM, 20.0 kHz width, ±5 kHz deviation, still widely used for amateur radio, NOAA weather radio, marine, and aviation users and land mobile users below 50 MHz [2] 11K2 F3E Narrow FM, 11.25 kHz bandwidth, ±2.5 kHz deviation – In the United States, all Part 90 Land Mobile Radio Service (LMRS) users operating above 50 MHz were required to ...