All Products for US Patent 4727534 - Timing and carrier recovery in dual polarization communications systems

Inventor(s): Debus, Jr.; Walter (Nottingham, NH), Kavehrad; Mohsen (Holmdel, NJ)

Owner: American Telephone and Telegraph Company (New York, NY), Bell Telephone Laboratories (Murray Hill, NJ)

Filing Date: August 19, 1986

Issue Date: February 23, 1988

Abstract: A technique is disclosed for improving the recovery of data signals transmitted on orthogonally polarized carrier signals by creating redundancy with respect to timing and carrier information. In the receiver, the carrier and timing recovery circuitry, which controls the recovery of the data signals from the incoming orthogonally polarized carrier signals, operate in response to a selected one of the carrier signals or at least one data signal recovered from this selected carrier signal. This selection is based on an examination of the data signals recovered from each of the orthogonally polarized carrier signals. Use of the described technique advantageously lessens the possibility of the carrier and timing recovery circuits losing synchronous operation during fading as it is less likely that a fade will simultaneously affect both orthogonally polarized carrier signals. As a result, data signal recovery is improved.