초록 ▼

A linearizer for a non-linear transmitter includes a tap delay line that provides samples of an input signal at selected times. At least one Volterra tap is coupled to the tape delay line. The Volterra tap includes a lookup table representation of a polynomial. An adaptive controller is coupled to t

A linearizer for a non-linear transmitter includes a tap delay line that provides samples of an input signal at selected times. At least one Volterra tap is coupled to the tape delay line. The Volterra tap includes a lookup table representation of a polynomial. An adaptive controller is coupled to the Volterra tap for modifying values in the lookup table.

대표청구항 ▼

1. A linearized transmitter, comprising: a tap delay line operable to provide samples of an input signal at selected times;multiple Volterra taps coupled to the tap delay line, each Volterra tap comprising a lookup table representation of a polynomial; andan adaptive controller coupled to the Volter

1. A linearized transmitter, comprising: a tap delay line operable to provide samples of an input signal at selected times;multiple Volterra taps coupled to the tap delay line, each Volterra tap comprising a lookup table representation of a polynomial; andan adaptive controller coupled to the Volterra tap operable to add outputs from the Volterra taps and to modify values in the lookup table to provide a predistorted version of the input sample; anda non-linear amplifier coupled to the adaptive controller and operable to amplify the predistorted version of the input sample to provide an amplified and linearized output. 2. A transmitter as defined in claim 1, wherein the tap delay line comprises an array of delay elements with tap-spacing of N samples. 3. A transmitter as defined in claim 1, wherein the tap delay line comprises elements distributed across the Volterra tap inputs and outputs. 4. A transmitter as defined in claim 1, further comprising an error module coupled to an output of the non-linear amplifier and a delay compensated input signal, the error module being operable to provide an error signal to the adaptive controller. 5. A transmitter as defined in claim 4, further comprising a causality delay module operable to shift the location of the present tap by a desired number of samples back in time and virtually create non-causal inverse models which work on past, present and future input samples. 6. A transmitter as defined in claim 5, wherein the adaptive controller is operable to provide a sample-by-sample lookup table value optimization. 7. A transmitter as defined in claim 6, wherein the adaptive controller is operable to modify a lookup table Volterra tap location value by reading its current value, modifying it with a processed error, and writing the new value to the same lookup table location. 8. A transmitter as defined in claim 1, wherein main X-terms can be created by connecting Volterra tap inputs to different outputs from the tap-delay line. 9. A transmitter as defined in claim 1, wherein the tap delay line is operable to hold a history of the evolution of the input such that different polynomials may be applied across time. 10. A transmitter as defined in claim 1, wherein the adaptive controller is operable to use at least two Volterra taps for a sample to provide main X-terms for the sample. 11. A method of linearizing a transmitter, comprising: applying an input signal to a tap delay line to provide samples of the input signal at selected times;coupling multiple Volterra taps to the tap delay line, each Volterra tap comprising a lookup table representation of a polynomial; andadding outputs from the Volterra taps and modifying values in the lookup table to provide a predistorted version of the input sample; andapplying the predistorted version of the input signal to a non-linear amplifier to amplify the predistorted version of the input sample to provide an amplified and linearized output. 12. A method as defined in claim 11, wherein the tap delay line comprises an array of delay elements with tap-spacing of N samples. 13. A method as defined in claim 11, wherein the tap delay line comprises elements distributed across the Volterra tap inputs and outputs. 14. A method as defined in claim 11, further comprising comparing an output of the non-linear amplifier and a delay compensated input signal to provide an error signal to the adaptive controller. 15. A method as defined in claim 14, further comprising shifting the location of the present tap by a desired number of samples back in time to virtually create non-causal inverse models which work on past, present and future input samples. 16. A method as defined in claim 15, further comprising providing a sample-by-sample lookup table value optimization. 17. A method as defined in claim 16, further comprising modifying a lookup table Volterra tap location value by reading its current value, modifying it with a processed error, and writing the new value to the same lookup table location. 18. A method as defined in claim 11, further comprising creating main X-terms by connecting Volterra tap inputs to different outputs from the tap-delay line. 19. A method as defined in claim 11, further comprising holding a history of the evolution of the input in the tap delay line such that different polynomials may be applied across time. 20. A method as defined in claim 11, further comprising using at least two Volterra taps for a sample to provide main X-terms for the sample.