Method and system for temporal autocorrelation filtering
First Claim
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1. A spread spectrum receiver, comprising:
- an antenna for receiving a spread spectrum signal;
a lattice filter coupled to the antenna, wherein the lattice filter is configured to remove magnitude distortion from the spread spectrum signal to produce a lattice filter output;
an autocorrelation filter coupled to receive the lattice filter output, wherein the autocorrelation filter is configured to remove phase distortion from the lattice filter output;
a correlation stage included in the autocorrelation filter to receive the lattice filter output and perform a set of time-shifted correlations on the lattice filter output;
an array of correlators included in the correlation stage, each of the correlators coupled to receive delayed versions of the lattice filter output and generate a respective correlation output; and
an integration stage coupled to the correlation stage to integrate each output of the correlation stage, wherein the integrating of each output of the correlation stage over the period of time generates a running impulse response characterizing the phase distortion of the spread spectrum signal.
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Abstract
An autocorrelation filter for use with a spread spectrum receiver. The autocorrelation filter can be used as a prefilter stage to reduce phase distortion present in a spread spectrum signal. The autocorrelation filter can be used to process the output from a lattice filter. The lattice filter is configured to remove magnitude distortion from the spread spectrum signal. The autocorrelation filter performs a series of correlations on the output of the lattice filter. The results of these correlations are integrated over a period of time to generate a running impulse response for characterizing and removing the phase distortion in the spread spectrum signal.
80 Citations
20 Claims
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1. A spread spectrum receiver, comprising:
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an antenna for receiving a spread spectrum signal; a lattice filter coupled to the antenna, wherein the lattice filter is configured to remove magnitude distortion from the spread spectrum signal to produce a lattice filter output; an autocorrelation filter coupled to receive the lattice filter output, wherein the autocorrelation filter is configured to remove phase distortion from the lattice filter output; a correlation stage included in the autocorrelation filter to receive the lattice filter output and perform a set of time-shifted correlations on the lattice filter output; an array of correlators included in the correlation stage, each of the correlators coupled to receive delayed versions of the lattice filter output and generate a respective correlation output; and an integration stage coupled to the correlation stage to integrate each output of the correlation stage, wherein the integrating of each output of the correlation stage over the period of time generates a running impulse response characterizing the phase distortion of the spread spectrum signal. - View Dependent Claims (2, 3, 4)
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5. A spread spectrum receiver, comprising:
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an antenna for receiving a spread spectrum signal; an autocorrelation filter coupled to the antenna, wherein the autocorrelation filter is configured to remove phase distortion from the spread spectrum signal received by the antenna; an analog to digital converter coupled to the antenna for converting the spread spectrum signal to a digital signal and providing the digital signal to the autocorrelation filter; a correlation stage included in the autocorrelation filter to receive the spread spectrum signal from the antenna and perform a set of time-shifted correlations on the spread spectrum signal; an array of correlators included in the correlation stage, each of the correlators coupled to receive delayed versions of the spread spectrum signal received by the antenna and generate a respective correlation output; and an integration stage coupled to the correlation stage to integrate each output of the correlation stage, wherein the integrating of each output of the correlation stage over the period of time generates a running impulse response characterizing the phase distortion of the spread spectrum signal. - View Dependent Claims (6, 7)
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8. An autocorrelation filter for removing phase distortion from a spread spectrum signal, wherein the autocorrelation filter is configured to function with a digitized spread spectrum signal, comprising:
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a correlation stage included in the autocorrelation filter to receive the spread spectrum signal and perform a correlation on the spread spectrum signal; an array of correlators included in the correlation stage, each of the correlators coupled to receive the spread spectrum signal and generate a respective correlation output; an integration stage coupled to the correlation stage for integrating the outputs of the correlation stage; an array of correlators included in the correlation stage, each of the correlators coupled to receive the spread spectrum signal and generate respective correlation outputs; and a leaky integrator included in the integration stage, the leaky integrator coupled to receive the respective correlation outputs and integrate the respective correlation outputs over a time period, wherein the integrating of the output of the correlation stage over the period of time generates a running impulse response characterizing the phase distortion of the spread spectrum signal. - View Dependent Claims (9, 10, 11, 12)
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13. A method for filtering out phase distortion from a spread spectrum receiver, comprising:
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receiving a spread spectrum signal; digitizing the spread spectrum signal; removing magnitude distortion from the spread spectrum signal by using a lattice filter; removing phase distortion from the spread spectrum signal by using an autocorrelation filter; generating a plurality of correlation outputs by using an array of correlators, each of the correlators coupled to receive an output of the lattice filter; and integrating the plurality of correlation outputs by using an integration stage coupled to receive the plurality of correlation outputs, wherein the integrating of the plurality of correlation outputs over the period of time generates a running impulse response characterizing the phase distortion of the spread spectrum signal. - View Dependent Claims (14, 15, 16)
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17. A method for filtering out phase distortion from a spread spectrum receiver, comprising:
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receiving a spread spectrum signal; digitizing the spread spectrum signal; removing phase distortion from the spread spectrum signal by using an autocorrelation filter; generating a plurality of correlation outputs by using an array of correlators, each of the correlators coupled to receive a digitized spread spectrum signal; and integrating the plurality of correlation outputs by using an integration stage coupled to receive the plurality of correlation outputs, wherein the integrating of the plurality of correlation outputs over the period of time generates a running impulse response characterizing the phase distortion of the spread spectrum signal. - View Dependent Claims (18, 19, 20)
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Specification