Low power and low complexity adaptive self-linearization
View Patent ↗A digital signal processing system comprising: an input terminal to receive an input signal that includes a distorted component and an undistorted component, the input signal having a sampling rate of R; and an adaptive self-linearization module coupled to the input terminal, to perform self-linearization based at least in part on the input signal to obtain an output signal that is substantially undistorted, wherein: the adaptive self-linearization module is to generate a replica distortion signal that is substantially similar to the distorted component, the generation being based at least in part on a target component having a sampling rate of R/L, L being an integer greater than 1; the adaptive self-linearization module includes a first digital signal processor (DSP) that is adapted to obtain a filter transfer function that approximates a system distortion transfer function, and a second DSP that is configured using configuration parameters of the first DSP.
1. A method of signal processing, comprising:
receiving an input signal that includes a distorted component and an undistorted component, the input signal having a sampling rate of R; and
performing self-linearization based at least in part on the input signal to obtain an output signal that is substantially undistorted; wherein:
performing self-linearization includes:
generating a replica distortion signal that is substantially similar to the distorted component, the generation being based at least in part on a target component having a sampling rate of R/L, L being an integer greater than 1, and including adapting a first digital signal processor (DSP) to obtain a filter transfer function that approximates a system distortion transfer function; and
sending configuration parameters of the first DSP to a second DSP to configure the second DSP.
2. The method of claim 1 , wherein the second DSP is a nonlinear DSP.
3. The method of claim 1 , further comprising configuring the second DSP to duplicate the filter transfer function.
4. The method of claim 1 , further comprising, at the second DSP, receiving the input signal and generating the target component.
5. The method of claim 1 , wherein the undistorted component is band limited to a frequency band, and the method further comprises filtering the input signal with a band-specific filter to suppress signal components within the frequency band to generate a reference component.
6. The method of claim 1 , wherein performing self-linearization further includes separating from the input signal a reference component and the target component.
7. The method of claim 6 , wherein separating the reference component and the target component includes adapting a persistence filter.
8. The method of claim 6 , wherein separating the reference component and the target component includes adapting a persistence filter that comprises:
a first memory to store a plurality of input samples;
an input sample selector to select an input sample from the plurality of input samples;
a second memory to store a plurality of adaptable filter coefficients;
a coefficient selector to select an adaptable filter coefficient from the plurality of adaptable filter coefficients;
a shared operator coupled to the input sample selector and the coefficient selector, to perform an operation on the selected input sample and the selected adaptable filter coefficient; and
an update block coupled to the second memory, to update the plurality of adaptive filter coefficients.
9. The method of claim 6 , wherein the undistorted component is band limited to a frequency band, and the method further comprises filtering the input signal with a band-specific filter to suppress signal components within the frequency band to generate the reference component.
10. The method of claim 6 , wherein the undistorted component is band limited to a frequency band, and the method further comprises filtering the input signal with a band-specific filter that attenuates signal components outside the frequency band to generate the target component.
11. The method of claim 1 , wherein the input signal is an unknown signal.
12. A digital signal processing system comprising:
an input terminal to receive an input signal that includes a distorted component and an undistorted component, the input signal having a sampling rate of R; and
an adaptive self-linearization module coupled to the input terminal, to perform self-linearization based at least in part on the input signal to obtain an output signal that is substantially undistorted, wherein:
the adaptive self-linearization module is to generate a replica distortion signal that is substantially similar to the distorted component, the generation being based at least in part on a target component having a sampling rate of R/L, L being an integer greater than 1; and
the adaptive self-linearization module includes:
a first digital signal processor (DSP) to obtain a filter transfer function that approximates a system distortion transfer function; and
a second DSP that is configurable using configuration parameters of the first DSP.
13. The system of claim 12 , wherein the second DSP is a nonlinear DSP.
14. The system of claim 12 , wherein the second DSP duplicates the filter transfer function.
15. The system of claim 12 , wherein the second DSP is configured to receive the input signal and generate the target signal.
16. The system of claim 12 , wherein the undistorted component is band limited to a frequency band, and the adaptive self-linearization module further comprises a band-specific filter configured to filter the input signal to suppress signal components within the frequency band to generate a reference component.
17. The system of claim 12 , wherein the adaptive self-linearization module comprises a separation filter configured to separate from the input signal a reference component and the target component.
18. The system of claim 17 , wherein the separation filter includes a persistence filter configured to separate the reference component and the target component.
19. The system of claim 17 , wherein the separation filter includes a persistence filter configured to separate the reference component and the target component, and the persistence filter comprises:
a first memory configured to store a plurality of input samples;
an input sample selector configured to select an input sample from the plurality of input samples;
a second memory configured to store a plurality of adaptable filter coefficients;
a coefficient selector configured to select an adaptable filter coefficient from the plurality of adaptable filter coefficients;
a shared operator coupled to the input sample selector and the coefficient selector, to perform an operation on the selected input sample and the selected adaptable filter coefficient; and
an update block coupled to the second memory, to update the plurality of adaptive filter coefficients.
20. The system of claim 17 , wherein the undistorted component is band limited to a frequency band, and the adaptive self-linearization module further comprises a band-specific filter that is to attenuate signal components outside the frequency band to generate the target component.
21. The system of claim 12 , wherein the input signal is an unknown signal.