Telephonic communications – Subscriber line or transmission line interface – Network interface device
Patent
1990-01-22
1991-03-19
Dwyer, James L.
Telephonic communications
Subscriber line or transmission line interface
Network interface device
379 3, 379406, H04B 324
Patent
active
050017470
ABSTRACT:
A method for estimating an amount of phase roll on a transmission channel. A signal of known frequency is transmitted over the channel by a near end modem. An average noise autocorrelation matrix is subtracted from an average signal plus noise autocorrelation matrix, both as received by a near end modem. The eigenvector of the resulting matrix is computed. The complex root of a quadratic with coefficients equal to the eigenvector elements is computed to solve for a difference between the frequency of the transmitted signal and the echoed receive signal to determine the phase roll.
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Dwyer James L.
Miller Jerry A.
Racal Data Communications Inc.
Shehata M.
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