Pulse or digital communications – Systems using alternating or pulsating current – Plural channels for transmission of a single pulse train
Patent
1996-04-03
1998-10-06
Pham, Chi H.
Pulse or digital communications
Systems using alternating or pulsating current
Plural channels for transmission of a single pulse train
375283, 375298, 375308, 329304, 332103, H04L 512, H04L 2732
Patent
active
058188754
ABSTRACT:
A modulation and demodulation method for communication between a transmitting side and a receiving side includes a step of at the transmitting side, producing a modulating signal, an amplitude ratio of a current instantaneous amplitude of the modulating signal and an instantaneous amplitude at n symbols previously in time (n is a natural number) of the modulating signal being set to correspond to a code to be transmitted, a step of at the transmitting side, modulating a carrier with a radio frequency or an intermediate frequency by the modulating signal to provide and transmit a modulated signal, a step of at the receiving side, receiving the transmitted modulated signal to provide a received signal, and a step of at the receiving side, deciding the transmitted code from an amplitude ratio of an instantaneous amplitude of a signal point in a signal space and an instantaneous amplitude of the signal point in the signal space n symbols previously in time with respect to the received signal. A first amplitude ratio value equal to or smaller than 1 and a second amplitude ratio value equal to or greater than 1 are prepared. The amplitude ratio is selected one of the first and second amplitude values so as to prevent the modulating signal from converging to zero and from diverging.
REFERENCES:
patent: 5113415 (1992-05-01), Muto
patent: 5363410 (1994-11-01), Hayashi
patent: 5394110 (1995-02-01), Mizoguchi
"Modulation Methods for PCNs", WEBB, IEEE Communications Magazine, vol. 30, No.21, Dec. 1992, pp. 90-95.
"Bandwidth Efficient QAM Schemes for Rayleigh Fading Channels", WEBB et al, IEE Proceedings-I Solid-State and Electron Devices, vol. 138, No. 3, Jun. 1991, pp. 169-175.
"Differentially Amplitude and Phase Encoded QAM on Rayleigh Fading Channels", CHUNG, Proceedings of the Military Communications Conference, Nov. 6-8, 1995, pp. 1026-1030.
"Bandwidth Efficient QAM Schemes for Rayleigh Fading Channels", WEBB et al, IEE Proceedings-1, vol. 138. No. 3, Jun. 1991, pp. 169-175.
Shirato Tadashi
Suzuki Yoshifumi
Luther William
Nippon Telegraph and Telephone Corporation
Pham Chi H.
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