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| Need for Frequency Modulation |
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| (i) Various electrical machines and noises cause amplitude disturbance in the transmission of amplitude-modulated wave. This makes the reception noisy. So, there is a need for different type of modulation, which can reduce the noise factor. Frequency modulation (FM) was proposed as a means of improving the signals-to-noise ratio of a radio system. The first practical system was put forward in 1936 as an alternative to AM in an effort to make radio transmissions more resistance to noise. |
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| (ii) Fidelity or audio quality of amplitude-modulated transmission is poor. This types of transmission is also not good for musical programmes. There is a need to eliminate amplitude-sensitive noise. This is possible if we eliminate amplitude variations. In other words, there is a need to keep the amplitude of the carrier constant. This is precisely what we do in frequency modulation. |
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