Pulse or digital communications – Receivers – Particular pulse demodulator or detector
Patent
1997-05-06
2000-02-29
Vo, Don N.
Pulse or digital communications
Receivers
Particular pulse demodulator or detector
H04L 2706
Patent
active
060318821
ABSTRACT:
Method and apparatus for using a plurality of correlators to improve the estimate of direct signal arrival time by identifying detailed features of a correlation function at and adjacent to the correlation peak. The errors in location of the center point of a correlation function R(.tau.), formed by the received signal and a stored copy of the expected signal, are assumed to be strongly correlated for narrow sample spacing and wide sample spacing of the correlation function. Alternatively, the multipath signal strengths and phases are estimated by a least mean squares analysis, using multiple sampling of a correlation function of an expected signal and an arriving composite signal that includes the direct signal and one or more multipath signals. Times of arrival or path delays of the direct signal and the multipath signals are determined separately. Path delays can be determined by at least three approaches: (1) identification of slope transition points in the correlation function R(.tau.); (2) Cepstrum processing of the received signal, using Fourier transform and inverse transform analysis; and (3) use of a grid of time shift points for the correlation function, and identification of time shift values, associated with certain solution parameters for a least mean squares analysis that have the largest absolute values, as times of arrival of the direct and multipath signals. Separate identification of path delays reduces the least mean squares analysis to a solvable linear problem. A modified received signal is constructed, with multipath signal(s) approximately removed.
REFERENCES:
patent: 3537008 (1970-10-01), Lakatos
patent: 3542954 (1970-11-01), Flanagan
patent: 3566035 (1971-02-01), Noll et al.
patent: 3596182 (1971-07-01), Menard
patent: 3605018 (1971-09-01), Coviello
patent: 3662108 (1972-05-01), Flanagan
patent: 3869673 (1975-03-01), Close
patent: 3956585 (1976-05-01), Butler et al.
patent: 4053932 (1977-10-01), Yamaguti et al.
patent: 4127874 (1978-11-01), Iwasawa et al.
patent: 4314277 (1982-02-01), Pritchard et al.
patent: 4349915 (1982-09-01), Costas
patent: 4364093 (1982-12-01), Holmes
patent: 4457007 (1984-06-01), Gutleber
patent: 4669091 (1987-05-01), Nossen
patent: 4672638 (1987-06-01), Taguchi et al.
patent: 4797950 (1989-01-01), Rilling
patent: 5065242 (1991-11-01), Dieterich et al.
patent: 5081643 (1992-01-01), Schilling
patent: 5111298 (1992-05-01), Koo
patent: 5121211 (1992-06-01), Koo
patent: 5127051 (1992-06-01), Chan et al.
patent: 5142551 (1992-08-01), Borth et al.
patent: 5159708 (1992-10-01), Nakamura et al.
patent: 5164959 (1992-11-01), Cai et al.
patent: 5196936 (1993-03-01), Kobayashi et al.
patent: 5203016 (1993-04-01), Belcher et al.
patent: 5218359 (1993-06-01), Minamisono
patent: 5241317 (1993-08-01), Howard
patent: 5303264 (1994-04-01), Ohsawa
patent: 5402450 (1995-03-01), Lennen
patent: 5414729 (1995-05-01), Fenton
patent: 5465413 (1995-11-01), Enge et al.
patent: 5493588 (1996-02-01), Lennen
Enge Per
Farmer Dominic
Schipper John F.
Schipper John F.
Trimble Navigation Limited
Vo Don N.
LandOfFree
Adaptive equalization of multipath signals does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Adaptive equalization of multipath signals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Adaptive equalization of multipath signals will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-689877