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AssigneeAgere Systems Inc.
InventorsSomnath Banik, Joseph M. Cannon, Eric J. Diethorn, Jeffrey P. Grundvig, James A. Johanson, Richard L. McDowell, Philip D. Mooney, Jian Wu
Estimating the term…
A method and apparatus to perform a real-time drift correction of a remote handset's local oscillator in a digital cordless telephone. The remote handset begins in a standby (sniff) mode. The remote handset periodically wakes from a sleep mode and goes into a normal link verification mode. Once in the link verification mode, the remote handset enters a time division duplexing (TDD) mode and attempts to establish a link with a base unit based on the timing of the TDD data frame. After the remote handset establishes a link with the base unit, the remote handset requests a security word from the base unit. Upon receiving the requested security word, the remote handset determines if the requested security word matches a security word of the remote handset. The remote handset implements a software frequency adjustment of its local oscillator. Once per frame, the remote handset enters a timing recovery state where the current state of the frame is compared with a previous state. When the cumulative timing slip is greater than a designated threshold, a frequency adjustment is made. During this exchange of commands between the remote handset and base unit, the remote handset continuously adjusts its local oscillator to achieve frequency alignment within, e.g., 1 part per million (ppm). Alternatively, frequency alignment may be achieved to a specified value.
A method to frequency align a local oscillator of a remote handset with a clock signal of a base unit of a digital cordless telephone, said method comprising:
An apparatus to frequency align a remote handset with a base unit of a digital cordless telephone, said apparatus comprising:
A method to frequency align a local oscillator of a remote handset with that of a base unit of a digital cordless telephone, said method comprising:
An apparatus to frequency align a remote handset with a base unit of a digital cordless telephone, said apparatus comprising:
An apparatus to frequency align a local oscillator of a remote handset with that of a base unit of a digital cordless telephone, said method comprising:
Dependencies are inferred from the claim text.