Transmit filter
First Claim
1. A transmit filter for generating an oversampled signal from a stream of data symbols generated responsive to a symbol clock, comprising:
- circuitry for receiving the data symbol stream;
phase tracking circuitry, responsive to a reference clock generated independently from the symbol clock, for maintaining phase information relative to the symbol clock; and
sample generating circuitry for generating samples responsive to said phase information.
1 Assignment
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Accused Products
Abstract
A transmit filter (100) receives a stream of data symbols (DT_TX) at a baseband symbol clock rate. An available clock (FREF) is used to generate sample points for producing a generating an oversampled signal. The available clock is independent from the baseband symbol clock, and does not need to be an integer multiple of the clock. Upon identifying a start sequence in the data stream, a phase tracking circuit (106) is used to determine a current position relative to the baseband symbol clock. A state circuit (104) stores the last three, or more, data symbols. Based on the last three data symbols (which determines the shape of the curve for the current data symbol) and the current position (which determines the current position on the curve), a filter circuit (108) generates a sample point.
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Citations
36 Claims
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1. A transmit filter for generating an oversampled signal from a stream of data symbols generated responsive to a symbol clock, comprising:
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circuitry for receiving the data symbol stream; phase tracking circuitry, responsive to a reference clock generated independently from the symbol clock, for maintaining phase information relative to the symbol clock; and sample generating circuitry for generating samples responsive to said phase information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of generating an oversampled signal from a stream of data symbols generated responsive to a symbol clock, comprising the steps of:
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receiving the data symbol stream; maintaining phase information relative to the symbo in clock in response to a reference clock generated independently from the symbol clock; and generating samples responsive to said phase information and said reference clock. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A transmit filter for generating an oversampled signal from a stream of data symbols generated responsive to a symbol clock, comprising:
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circuitry for receiving the data symbol stream; phase tracking circuitry, responsive to a reference clock, for maintaining phase information relative to the symbol clock; and sample generating circuitry for selectively generating samples responsive to said phase information and said symbol clock. - View Dependent Claims (35, 36)
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Specification