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Digital modulation schemes are possible because the transmitter-receiver pair has prior knowledge of how data is encoded and represented in the communications system. In all digital communication systems, both the modulator at the transmitter and the demodulator at the receiver are structured so that they perform inverse operations.
These FM systems are unusual, in that they have a ratio of carrier to maximum modulation frequency of less than two; contrast this with FM audio broadcasting, where the ratio is around 10,000. Consider, for example, a 6-MHz carrier modulated at a 3.5-MHz rate; by Bessel analysis, the first sidebands are on 9.5 and 2.5 MHz and the second ...
When a digital signal is to be transmitted over an analogue baseband channel, the modulation technique is termed line coding. Several keying techniques exist, including phase-shift keying, frequency-shift keying, and amplitude-shift keying. Bluetooth, for example, uses phase-shift keying to exchange information between devices.
Many PAPR (or crest factor) reduction techniques have been developed, for instance, based on iterative clipping. [30] Over the years, numerous model-driven approaches have been proposed to reduce the PAPR in communication systems.
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 .
In digital modulation, minimum-shift keying (MSK) is a type of continuous-phase frequency-shift keying that was developed in the late 1950s by Collins Radio employees Melvin L. Doelz and Earl T. Heald. [1]
Phase modulation (PM) is a modulation pattern for conditioning communication signals for transmission. It encodes a message signal as variations in the instantaneous phase of a carrier wave . Phase modulation is one of the two principal forms of angle modulation , together with frequency modulation .
Angle modulation is a class of carrier modulation that is used in telecommunications transmission systems. The class comprises frequency modulation (FM) and phase modulation (PM), and is based on altering the frequency or the phase , respectively, of a carrier signal to encode the message signal.