Method and apparatus for digitally equalizing a signal in a distributed antenna system
First Claim
1. A signal processing device within a distributed antenna system, the signal processing device comprising:
- a signal path within a signal processing board, the signal path having an uncompensated distortion function of G(ω
) with a system response represented by y(n); and
a compensator coupled to the signal path, the compensator having a finite impulse response (FIR) filter with an impulse response function represented by H(ω
), the compensator having an FIR filter parameter vector {right arrow over (h)} determined from an estimated system response y(n) of the signal path to an input comb signal x(n), wherein y(n) is estimated from interpolated measured output responses of the signal path to a plurality of frequency sweep signal test inputs.
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Abstract
Systems and methods for digitally equalizing a signal in a distributed antenna system are provided. In one embodiment, a signal processing device within a distributed antenna system comprises a signal path within a signal processing board, the signal path having an uncompensated distortion function of G(ω) with a system response represented by y(n); and a compensator coupled to the signal path, the compensator having a finite impulse response (FIR) filter with an impulse response function represented by H(ω), the compensator having an FIR filter parameter vector {right arrow over (h)} determined from an estimated system response y(n) of the signal path to an input comb signal x(n), wherein y(n) is estimated from interpolated measured output responses of the signal path to a plurality of frequency sweep signal test inputs.
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Citations
20 Claims
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1. A signal processing device within a distributed antenna system, the signal processing device comprising:
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a signal path within a signal processing board, the signal path having an uncompensated distortion function of G(ω
) with a system response represented by y(n); anda compensator coupled to the signal path, the compensator having a finite impulse response (FIR) filter with an impulse response function represented by H(ω
), the compensator having an FIR filter parameter vector {right arrow over (h)} determined from an estimated system response y(n) of the signal path to an input comb signal x(n), wherein y(n) is estimated from interpolated measured output responses of the signal path to a plurality of frequency sweep signal test inputs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for calibrating a signal processing board, the method comprising:
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setting a compensator within a first signal path of a signal processing board to have a flat response across a first pass band of the signal processing board; applying a plurality of test signals to an input of the signal processing board, the plurality of test signals spaced in frequency across the first pass band; determining a gain value for each of the plurality of test signals based on an output of the signal processing board; estimating a system response function y(n) for the signal processing board based on the gain value for each of the plurality of test signals; solving for coefficients of a vector h(n) based on a difference between a vector d(n) and a convolution h(n)*y(n), wherein d(n) represents an input to the system response function y(n) subject to a delay; and setting coefficients of a finite impulse response (FIR) filter within the compensator based on the coefficients of the vector h(n). - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A signal processing device within a distributed antenna system, the signal processing device comprising:
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a signal path within a signal processing board, the signal path having an uncompensated distortion function of G(ω
); anda compensator coupled to the signal path, the compensator having a finite impulse response (FIR) filter with an impulse response function represented by a vector {right arrow over (h)} and having filter coefficients h(n) of vector {right arrow over (h)} that are based on the relationship {right arrow over (Y)}{right arrow over (h)}={right arrow over (d)}, wherein {right arrow over (d)} is a vector representing an input to the signal path subject to a delay and {right arrow over (Y)} is a convolution matrix for an estimated response of the signal path to a comb signal, the estimated response based on interpolated measured output responses of the signal path to a plurality of frequency sweep signal test inputs. - View Dependent Claims (18, 19, 20)
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Specification