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where is the highest frequency component present in the modulating signal x m (t), and is the peak frequency-deviation – i.e. the maximum deviation of the instantaneous frequency from the carrier frequency. For a sine wave modulation, the modulation index is seen to be the ratio of the peak frequency deviation of the carrier wave to the ...
The modulation index (or modulation depth) of a modulation scheme describes by how much the modulated variable of the carrier signal varies around its unmodulated level. It is defined differently in each modulation scheme. Amplitude modulation index; Frequency modulation index; Phase modulation index
Motorola T5320 FRS handheld radio. The Family Radio Service (FRS) is an improved walkie-talkie radio system authorized in the United States since 1996. This personal radio service uses channelized frequencies around 462 and 467 MHz in the ultra high frequency (UHF) band.
Low-frequency radio range audio signals: N stream, A stream and combined uniform tone (simulated sounds) The low-frequency radio range, also known as the four-course radio range, LF/MF four-course radio range, A-N radio range, Adcock radio range, or commonly "the range", was the main navigation system used by aircraft for instrument flying in the 1930s and 1940s, until the advent of the VHF ...
In the 25 kHz channel spacing scheme, an upper audio frequency of 12.5 kHz would be theoretically possible. [19] However, most airband voice transmissions never actually reach these limits. Usually, the whole transmission is contained within a 6 kHz to 8 kHz bandwidth, corresponding to an upper audio frequency of 3 kHz to 4 kHz. [19]
The International Telecommunication Union uses an internationally agreed system for classifying radio frequency signals. Each type of radio emission is classified according to its bandwidth, method of modulation, nature of the modulating signal, and type of information transmitted on the carrier signal.
Shortwave bands are frequency allocations for use within the shortwave radio spectrum (the upper medium frequency [MF] band and all of the high frequency [HF] band). Radio waves in these frequency ranges can be used for very long distance (transcontinental) communication because they can reflect off layers of charged particles in the ionosphere and return to Earth beyond the horizon, a ...
In Canada, the United States, Mexico, the Bahamas, etc., there are 101 FM channels numbered from 200 (center frequency 87.9 MHz) to 300 (center frequency 107.9 MHz), though these numbers are rarely used outside the fields of radio engineering and government. The center frequencies of the FM channels are spaced in increments of 200 kHz.