Pre-distortion architecture for compensating non-linear effects
First Claim
1. A method for reducing distortion in an output signal by applying pre-distortion to an input signal to generate a pre-distorted signal, such that, when the pre-distorted signal is applied to a non-linear system to generate the output signal, the pre-distortion reduces the distortion in the output signal, wherein the pre-distorted signal is generated by:
- (a) generating a first frequency-dependent pre-distortion signal corresponding to a product of (i) a derivative of a first pre-distortion function and (ii) the input signal;
(b) generating a second frequency-dependent pre-distortion signal corresponding to a product of (i) a derivative of a second pre-distortion function and (ii) the input signal;
(c) generating a third frequency-dependent pre-distortion signal corresponding to a product of (i) a third pre-distortion function and (ii) a derivative of the input signal;
(d) generating a fourth frequency-dependent pre-distortion signal corresponding to a product of (i) a fourth pre-distortion function and (ii) the derivative of the input signal; and
(e) generating the pre-distorted signal based on a combination of the first, second, third, and fourth frequency-dependent pre-distortion signals.
19 Assignments
0 Petitions
Accused Products
Abstract
An input signal is pre-distorted to reduce distortion resulting from subsequent signal amplification. Frequency-dependent pre-distortion is preferably implemented in combination with frequency-independent pre-distortion, where the frequency-dependent pre-distortion is generated by expanding the derivative of a product of a pre-distortion function and the input signal and then relaxing constraints on the pre-distortion function and/or on frequency-dependent filtering associated with the frequency-dependent pre-distortion. In one implementation, four different frequency-dependent pre-distortion signals are generated for the expansion using up to four different pre-distortion functions and up to four different frequency-dependent filters.
89 Citations
26 Claims
-
1. A method for reducing distortion in an output signal by applying pre-distortion to an input signal to generate a pre-distorted signal, such that, when the pre-distorted signal is applied to a non-linear system to generate the output signal, the pre-distortion reduces the distortion in the output signal, wherein the pre-distorted signal is generated by:
-
(a) generating a first frequency-dependent pre-distortion signal corresponding to a product of (i) a derivative of a first pre-distortion function and (ii) the input signal; (b) generating a second frequency-dependent pre-distortion signal corresponding to a product of (i) a derivative of a second pre-distortion function and (ii) the input signal; (c) generating a third frequency-dependent pre-distortion signal corresponding to a product of (i) a third pre-distortion function and (ii) a derivative of the input signal; (d) generating a fourth frequency-dependent pre-distortion signal corresponding to a product of (i) a fourth pre-distortion function and (ii) the derivative of the input signal; and (e) generating the pre-distorted signal based on a combination of the first, second, third, and fourth frequency-dependent pre-distortion signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 26)
-
-
14. Apparatus for reducing distortion in an output signal by applying pre-distortion to an input signal to generate a pre-distorted signal, such that, when the pre-distorted signal is applied to a non-linear system to generate the output signal, the pre-distortion reduces the distortion in the output signal, wherein apparatus comprises:
-
a first signal path configured to generate a first frequency-dependent pre-distortion signal corresponding to a product of (i) a derivative of a first pre-distortion function and (ii) the input signal; a second signal path configured to generate a second frequency-dependent pre-distortion signal corresponding to a product of (i) a derivative of a second pre-distortion function and (ii) the input signal; a third signal path configured to generate a third frequency-dependent pre-distortion signal corresponding to a product of (i) a third pre-distortion function and (ii) a derivative of the input signal; a fourth signal path configured to generate a fourth frequency-dependent pre-distortion signal corresponding to a product of (i) a fourth pre-distortion function and (ii) the derivative of the input signal; and a summer configured to generate the pre-distorted signal based on the first, second, third, and fourth frequency-dependent pre-distortion signals. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
-
Specification