| 摘要 |
FIELD: physics, communications. ^ SUBSTANCE: present invention relates to modulation and demodulation methods and can be used for multilevel quadrature amplitude modulation and demodulation. The modulation device includes a Gray coding circuit into which data (2n+1) bits (where n is a number greater than 1) are entered and which codes 2 bits of an input signal from (2n+1) bits into a Gray code as a signal for identifying four quadrants, a coding circuit which codes 3 bits of the input signal from (2n+1) bits as a signal which indicates one of eight subgroups presented in each of the four quadrants such that, the average Hamming distance between neighbouring subgroups inside a quadrant remains minimal, and a conversion circuit which displays binary data coded by the Gray coding network and the circuit for coding into four quadrants. ^ EFFECT: reduced frequency of errors. ^ 12 cl, 12 dwg |
