Compensating for spectral attenuation

1. A method to compensate for spectral attenuation, comprising:

determining spectral attenuation for a communications channel;

creating a first filter for said attenuation; and

compensating for said attenuation using said first filter;

wherein said determining comprises;

receiving a L sequence signal; and

modeling spectral attenuation of said L sequence signal as a second filter.

2. The method of claim 1 , wherein said creating comprises determining a phase and magnitude for said first filter based on said second filter, with said phase identifying an attenuated frequency and said magnitude identifying a level of attenuation for said frequency.

3. The method of claim 2 , wherein determining said phase comprises:

performing an N point Fast Fourier Transform (FFT) on said L sequence signal;

identifying a minimal frequency component;

identifying a sampling frequency; and

determining said phase from said minimal frequency component and said sampling frequency.

4. The method of claim 3 , further comprising confirming said minimal frequency component.

5. The method of claim 4 , wherein said determining said phase from said minimal frequency component and said sampling frequency is performed in accordance with Ø=2*PI*f i /f s , where Ø represents said phase, f i represents said attenuated frequency, and f s represents a sampling frequency.

6. The method of claim 5 , wherein said determining said magnitude comprises:

normalizing said FFT;

determining an average power for said FFT;

identifying a minimal power for said FFT; and

determining said magnitude using said average power and said minimal power.

7. The method of claim 6 , wherein said determining said magnitude using said average power and said minimal power is performed in accordance with M=1−(P av −P min ), where M represents said magnitude, P av represents said average power, and P min represents said minimal power.

8. The method of claim 1 , wherein said first filter is a single pole filter.

9. The method of claim 1 , wherein said second filter is a single-zero filter.

10. A compensation module, comprising:

a filter design module to receive a L sequence signal and design a set of filter parameters to compensate for spectral attenuation of a communication channel; and

a filter connected to said filter design module to receive said filter parameters and use said filter parameters to compensate for said spectral attenuation;

wherein said filter parameters comprise a phase and magnitude for a single-zero filter.

11. The compensation module of claim 10 , wherein said filter is a single pole filter.

12. A modem comprising:

an encoder;

a transmitter connected to said encoder;

an analog front end connected to said transmitter;

a compensation module connected to said analog front end;

a receiver connected to said compensation module;

a decoder connected to said receiver; and

a channel estimator connected to said transmitter, said receiver and said compensation module;

wherein said compensation module comprises:

a filter design module; and

a filter connected to said filter design module;

wherein said filter design module receives a L sequence signal and designs a set of filter parameters using said L sequence signal, and sends said filter parameters to said filter; and

said filter receives said filter parameters and uses said filter parameters to compensate for said spectral attenuation;

wherein said filter parameters comprise a phase and magnitude for single-zero filter.

13. An article comprising:

a storage medium;

said storage medium including stored instructions that, when executed by a processor, result in determining spectral attenuation for a communications channel, creating a filter for said attenuation during said determination, and compensating for said attenuation using said filter, wherein said determining comprises receiving a L sequence signal and modeling spectral attenuation of said L sequence signal as a second filter.

14. The article of claim 13 , wherein the stored instructions, when executed by a processor, further result in determining a set of filter parameters for said filter, with a first parameter being a phase determined in accordance with Ø=2*PI*f i /f s , where Ø represents said phase, f i represents an attenuated frequency, and f s represents a sampling frequency, and a second parameter being a magnitude determined in accordance with M=1−(P av −P min ), where M represents said magnitude, P av represents an average power, and P min , represents a minimal power.