Pulse or digital communications – Receivers – Angle modulation
Patent
1995-10-17
1997-05-06
Chin, Stephen
Pulse or digital communications
Receivers
Angle modulation
375232, 375284, 375329, 375346, 375350, 329308, 3647242, H04L 2714
Patent
active
056278616
ABSTRACT:
A carrier phase estimation apparatus include a base band converter and a phase estimator. A received IF signal is converted to an in-phase component In and an quadrature component Qn of a digital base band signal in the base band converter. In the phase estimator, a non-linear circuit executes a non-linear operation of the components In and Qn to output non-linearly converted in-phase component In' and quadrature component Qn' of the digital base band signal and the components In' and Qn' are input to a pair of filters. In each filter, the components In' or Qn' are stored into shift registers at a predetermined timing and the signals stored in the shift registers are multiplied by respective weighting factors C.sub.k in respective multipliers. The multiplied values are summed by an adder and the obtained sum is divided by a stage number N of the shift register in a divider to obtain filtering signals Xn and Yn. That is, the weighted averaging of the components In' and Qn' is taken in the filters and then the filtering signals are transformed in a coordinate transformer to calculate an estimated carrier phase .THETA.n. By taking the weighted average, the carrier phase fluctuating due to fading can be more precisely estimated. In an alternate embodiment, a polynomial approximation is conducted using the components stored in the shift registers to generate filtering signals.
REFERENCES:
patent: 3935535 (1976-01-01), Motley et al.
patent: 4644562 (1987-02-01), Kavehrad et al.
patent: 4975927 (1990-12-01), Yoshida
patent: 5049830 (1991-09-01), Yoshida
patent: 5185764 (1993-02-01), Baier
patent: 5239273 (1993-08-01), Hedstrom et al.
patent: 5245611 (1993-09-01), Ling et al.
patent: 5307157 (1994-04-01), Kobayashi et al.
patent: 5321726 (1994-06-01), Kafadar
patent: 5434889 (1995-07-01), Baier
Shahid Qureshi, Adaptive Equalization, Mar. 1982, pp. 9-16, 1982 IEEE.
S. Yoshida & H. Tomita "A New Coherent Demodulation Technique for Land-Mobile Satellite Communications" pp. 622-627.
R. Harris & M. Yarwood "Carrier Recovery & Inter-Burst Interference in a Symbol-Synchronous TDMA System" International Journal of Satellite Communications, vol. 9, 1991 pp. 197-208.
A. Viterbi "Nonlinear Estimation of PSK-Modulated Carrier Phase with Application to Burst Digital Transmission" IEEE 1983 pp. 543-551.
Chin Stephen
Le Amanda T.
Mitsubishi Denki & Kabushiki Kaisha
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