System and method for linear distortion estimation by way of equalizer coefficients

1. A method comprising:

normalizing one or more adaptive filter coefficients h 1 (n) associated with a signal by an adaptive equalizer to unit energy; and

differencing the normalized one or more adaptive filter coefficients h 1 (n) with an ideal response h 0 (n) of a communications channel, the differencing producing an error sequence h 2 (n).

2. The method of claim 1 , further comprising determining an energy of the error sequence h 2 (n).

3. The method of claim 1 , further comprising:

converting the error sequence h 2 (n) to frequency domain, the converting producing a frequency response H 2 (k) of the error sequence h 2 (n); and

removing a delay offset of the frequency response H 2 (k) to produce a delayed offset response H 3 (k).

4. The method of claim 3 , further comprising:

summing the delayed offset response H 3 (k) and an ideal channel frequency response and inverting the sum to produce an inverted response H 4 (k);

normalizing the inverted response H 4 (k) to unit power, thus producing a normalized inverted response H 5 (k); and

removing a phase offset from the normalized inverted response H 5 (k), the removing producing an estimated channel response H 6 (k).

5. The method of claim 4 , further comprising:

differencing the estimated channel response H 6 (k) with the ideal channel frequency response, the differencing producing an error filter response H 7 (k); and

determining an error power of the error filter response H 7 (k).

6. The method of claim 3 , wherein the converting is based upon a fast Fourier transform of the error sequence h 2 (n).

7. The method of claim 3 , wherein the converting is based upon padding the error sequence h 2 (n) with zeros and applying a fast Fourier transform (FFT) to the padded error sequence.

8. The method of claim 7 , wherein the FFT includes at least 4096 samples.

9. An apparatus for estimating channel distortion in a communications channel including an adaptive equalizer, comprising:

means for normalizing one or more adaptive filter coefficients h 1 (n) associated with a signal by the adaptive equalizer to unit energy; and

means for differencing the normalized one or more adaptive filter coefficients h 1 (n) with an ideal response h 0 (n) of the communications channel, the differencing producing an error sequence h 2 (n).

10. The apparatus of claim 9 , further comprising means for determining an energy of the error sequence h 2 (n).

11. The apparatus of claim 9 , further comprising:

means for converting the error sequence h 2 (n) to frequency domain, the converting producing a frequency response H 2 (k) of the error sequence h 2 (n); and

means for removing a delay offset of the frequency response H 2 (k) to produce a delayed offset response H 3 (k).

12. The apparatus of claim 11 , further comprising:

means for summing the delayed offset response H 3 (k) and an ideal channel frequency response and (ii) inverting the sum to produce an inverted response H 4 (k);

means for normalizing the inverted response H 4 (k) to unit power, thus producing a normalized inverted response H 5 (k); and

means for removing a phase offset from the normalized inverted response H 5 (k), the removing producing an estimated channel response H 6 (k).

13. The apparatus of claim 12 , further comprising:

means for differencing the estimated channel response H 6 (k) with the ideal channel frequency response, the differencing producing an error filter response H 7 (k); and

means for determining an error power of the error filter response H 7 (k).

14. A non-transitory computer readable medium having stored thereon computer executable instructions that, if executed by a processor, cause the computing device to perform a method comprising:

normalizing one or more adaptive filter coefficients h 1 (n) associated with a signal by an adaptive equalizer to unit energy; and

differencing the normalized one or more adaptive filter coefficients h 1 (n) with an ideal response h 0 (n) of a communications channel, the differencing producing an error sequence h 2 (n).

15. The non-transitory computer readable medium of claim 14 , further comprising determining an energy of the error sequence h 2 (n).

16. The non-transitory computer readable medium of claim 14 , further comprising:

converting the error sequence h 2 (n) to frequency domain, the converting producing a frequency response H 2 (k) of the error sequence h 2 (n); and

removing a delay offset of the frequency response H 2 (k) to produce a delayed offset response H 3 (k).

17. The non-transitory computer readable medium of claim 16 , further comprising:

summing the delayed offset response H 3 (k) and an ideal channel frequency response and inverting the sum to produce an inverted response H 4 (k);

normalizing the inverted response H 4 (k) to unit power, thus producing a normalized inverted response H 5 (k); and

removing a phase offset from the normalized inverted response H 5 (k), the removing producing an estimated channel response H 6 (k).

18. The non-transitory computer readable medium of claim 17 , further comprising:

differencing the estimated channel response H 6 (k) with the ideal channel frequency response, the differencing producing an error filter response H 7 (k); and

determining an error power of the error filter response H 7 (k).

19. The non-transitory computer readable medium of claim 16 , wherein the converting is based upon a fast Fourier transform of the error sequence h 2 (n).

20. The non-transitory computer readable medium of claim 16 , wherein the converting is based upon padding the error sequence h 2 (n) with zeros and applying a fast Fourier transform (FFT) to the padded error sequence.

21. The non-transitory computer readable medium of claim 20 , wherein the FFT includes at least 4096 samples.