Comb-assisted cyclostationary analysis
First Claim
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1. A signal analyzer for analyzing an input signal to remove noise, the signal analyzer comprising:
- a mutually coherent frequency comb pair comprising a first comb and a second comb, the second comb having a frequency pitch offset with respect to a frequency pitch of the first comb, each comb generating a plurality of optical tones, wherein the output of the first comb has mapped thereon the input signal, and wherein the comb pair generates a plurality of spectrally overlapping optical tone pairs, each overlapping optical tone pair comprising a single input signal copy from the first comb and a different optical tone from the second comb;
an optical demultiplexer configured for receiving the plurality of overlapping optical tone pairs and spectrally separating each overlapping optical tone pair into a plurality of sub-bands;
a detector array configured for receiving and converting each overlapping optical tone pair into an electrical frequency component of the input signal, wherein the detector array outputs a plurality of discrete Fourier transform (DFT) components corresponding to the plurality of overlapping optical tone pairs; and
a processor configured to determine a spectral correlation among the DFT components, wherein non-correlated DFT components represent noise and correlated DFT components represent signal, the processor further configured to average the correlated DFT components to generate a representation of the input signal with noise removed.
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Abstract
A photonically-assisted cyclostationary analyzer eliminates the need for high-bandwidth digitization and real-time Fourier processors by using mutually-coherent frequency combs to generate a Fourier representation of the received signal in a computation-free manner.
48 Citations
24 Claims
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1. A signal analyzer for analyzing an input signal to remove noise, the signal analyzer comprising:
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a mutually coherent frequency comb pair comprising a first comb and a second comb, the second comb having a frequency pitch offset with respect to a frequency pitch of the first comb, each comb generating a plurality of optical tones, wherein the output of the first comb has mapped thereon the input signal, and wherein the comb pair generates a plurality of spectrally overlapping optical tone pairs, each overlapping optical tone pair comprising a single input signal copy from the first comb and a different optical tone from the second comb; an optical demultiplexer configured for receiving the plurality of overlapping optical tone pairs and spectrally separating each overlapping optical tone pair into a plurality of sub-bands; a detector array configured for receiving and converting each overlapping optical tone pair into an electrical frequency component of the input signal, wherein the detector array outputs a plurality of discrete Fourier transform (DFT) components corresponding to the plurality of overlapping optical tone pairs; and a processor configured to determine a spectral correlation among the DFT components, wherein non-correlated DFT components represent noise and correlated DFT components represent signal, the processor further configured to average the correlated DFT components to generate a representation of the input signal with noise removed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 18)
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9. A method for cyclostationary (CS) analysis of an input signal, the method comprising:
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replicating the input signal onto a first optical frequency comb having a frequency pitch, the first optical frequency comb configured for generating a first plurality of optical tones, each optical tone of the first plurality having a replica of the input signal mapped thereon; generating a second plurality of optical tones using a second optical frequency comb having a pitch offset relative to the first optical frequency comb, the first and second optical frequency combs being frequency-locked by a common emission seed; splitting each replica from the first comb and at least one corresponding tone from the second comb into separate optical waveguides; receiving the output of each optical waveguide at a coherent receiver, each optical waveguide carrying a separated replica of the input signal and at least one corresponding tone from the second comb; converting each separated replica into an electrical sub-band of the input signal, wherein each electrical sub-band represents a discrete Fourier transform (DFT) component of the input signal; determining a spectral correlation among the DFT components, wherein non-correlated DFT components represent noise and correlated DFT components represent signal; and averaging correlated DFT components to generate a representation of the input signal with noise removed. - View Dependent Claims (10, 11, 12, 17)
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13. A method for cyclostationary (CS) analysis of an input signal, the method comprising:
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separating the input signal into a plurality of sub-bands by modulating the input signal onto a first optical frequency comb of a mutually-coherent optical comb pair, wherein the optical comb pair comprises a second optical frequency comb having a pitch offset relative to the first optical frequency comb, and wherein each sub-band corresponds to an optical tone in a spectral domain; and detecting and converting the optical tones into electrical subcomponents of the input signal, wherein each electrical subcomponent represents a discrete Fourier transform (DFT) component of the input signal; calculating a spectral correlation among the DFT components, wherein non-correlated DFT components represent noise and correlated DFT components represent signal; and averaging the correlated DFT components to reconstruct the input signal. - View Dependent Claims (14, 15, 16)
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19. A method for reconstructing an input signal, the method comprising:
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spectrally decomposing the input signal into a plurality of overlapping optical tone pairs by modulating the input signal onto a first optical frequency comb of a mutually-coherent optical comb pair, wherein the mutually-coherent optical comb pair comprises a second optical frequency comb having a pitch offset relative to the first optical frequency comb; detecting and converting the overlapping optical tone pairs into electrical subcomponents of the input signal, wherein each electrical subcomponent represents a discrete Fourier transform (DFT) component of the input signal; calculating a spectral correlation among the DFT components, wherein non-correlated DFT components represent noise and correlated DFT components represent signal; and averaging the correlated DFT components to reconstruct the input signal. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification