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Electronic Communications
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
The space that an AM signal occupies with its frequency is called a channel. The bandwidth of an AM channel is twice the highest modulating frequency. For our 1kHz modulating component, a 2-kHz bandwidth is needed, which would be 1 kHz above and below the carrier frequency of 1 MHz. In commercial AM broadcasting, a station is assigned a 10-kHz channel which limits the AM modulation component to a frequency of 5 kHz. Figure 7-19 shows the side-bands produced by a standard AM station.
Analog Radio
Published in Skip Pizzi, Graham A. Jones, A Broadcast Engineering Tutorial for Non-Engineers, 2014
In AM broadcasting, when the modulating signal (the audio program) is combined with the carrier, the varying-amplitude RF signal that results is made up of the original carrier frequency and additional frequencies known as the upper and lower sidebands (see Chapter 7). As described above, if the audio signal has frequencies extending to 10 kHz, then the sidebands will extend about 10 kHz above and below the carrier frequency, occupying at least 20 kHz of radio spectrum. In reality, transmitters may also produce additional energy in sidebands extending beyond these limits, which is referred to as splatter.
AM Considerations
Published in David P. Maxson, The IBOC Handbook, 2007
The term “legacy” is often used in technology circles to describe an old technology that has been eclipsed by modernity, but is still widely used. In “legacy” AM broadcasting, the information to be transmitted is simply a single audio-frequency waveform (0 to 10 kHz audio spectrum). Amplitude Modulation (AM) is a means of varying the power (amplitude) of a radio frequency carrier in order to transmit information while maintaining the frequency of the carrier constant.
The Changing Face of Public Broadcasting in India
Published in IETE Journal of Education, 2023
AM broadcasting remained as the mainstay for a long time and medium wave (MW) stations in the 550–1650 KHz frequency range formed the back bone of the regional services. Short wave stations in 3–30 MHz frequency bands, allocated by Wireless Allocation Radio Frequency Committee (WARC), were used for long distance broadcasting targeted at far flung corners of the world. The frequencies in the MW band had a restricted range during the daytime and SW stations had to change frequencies to take care of variations in the ionospheric conditions.