Modulation using quasi-parallel to serial conversion to reduce bandwidth
Modulation using quadra-pole sideband keying to generate spread spectrum signals
Modulation using Fast Fourier Transforms to generate frequencies at the first, second, third, and fourth harmonics of the carrier frequency to improve noise immunity
Modulation in which digital data is transmitted using 0-, 90-, 180- and 270-degrees phase shift to represent pairs of bits✓Bonne réponse
Explication
Quadrature phase shift keying uses four carrier phase states 90 degrees apart, and four distinct states encode two bits per symbol, which is why each symbol represents a pair of bits.