System and method for digital interference cancellation
First Claim
1. A receiver comprising:
- an input configured to receive an analog radio frequency input signal within a radio frequency band comprising a plurality of independently modulated signals;
a signal generator, configured to generate a nulling analog radio frequency signal which tracks a phase of an undesired signal of the plurality of independent signals over time;
a subtractor configured to receive a representation of the analog radio frequency signal and the nulling signal, and to produce a modified representation of the analog radio frequency signal with a diminished representation of the undesired signal; and
a digitizer having an instantaneous bandwidth of at least 10 MHz, receiving the modified representation, wherein the undesired signal of the representation of the analog radio frequency signal interferes with a representation of modulation information of at least one of the plurality of independently modulated signals in an output of the digitizer, and the modified representation of the analog radio frequency signal with a diminished representation of the undesired signal does not interfere with a representation of modulation information of at least one of the plurality of independently modulated signals in the output of the digitizer.
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Accused Products
Abstract
A system and method for receiving a signal, comprising an input adapted to receive a radio frequency signal having a strong interferer; a signal generator, adapted to produce a representation of the interferer as an analog signal generated based on an oversampled digital representation thereof; and a component adapted to cancel the strong interferer from radio frequency signal based on the generated analog signal to produce a modified radio frequency signal substantially absent the interferer. The system typically has a nonlinear component that either saturates or produces distortion from the strong interferer, which is thereby reduced. The system preferably employs high speed circuits which digitize and process radio frequency signals without analog mixers.
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Citations
20 Claims
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1. A receiver comprising:
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an input configured to receive an analog radio frequency input signal within a radio frequency band comprising a plurality of independently modulated signals; a signal generator, configured to generate a nulling analog radio frequency signal which tracks a phase of an undesired signal of the plurality of independent signals over time; a subtractor configured to receive a representation of the analog radio frequency signal and the nulling signal, and to produce a modified representation of the analog radio frequency signal with a diminished representation of the undesired signal; and a digitizer having an instantaneous bandwidth of at least 10 MHz, receiving the modified representation, wherein the undesired signal of the representation of the analog radio frequency signal interferes with a representation of modulation information of at least one of the plurality of independently modulated signals in an output of the digitizer, and the modified representation of the analog radio frequency signal with a diminished representation of the undesired signal does not interfere with a representation of modulation information of at least one of the plurality of independently modulated signals in the output of the digitizer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of receiving a signal, comprising:
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receiving an analog radio frequency input signal within a radio frequency band comprising a plurality of independently modulated signals; generating a nulling analog radio frequency signal which tracks a phase of an undesired signal of the plurality of independent signals over time; receiving a representation of the analog radio frequency signal and the nulling signal, and producing a modified representation of the analog radio frequency signal with a diminished representation of the undesired signal; and digitizing the modified representation of the analog radio frequency signal with a diminished representation of the undesired signal using a digitizer having an instantaneous bandwidth of at least 10 MHz, wherein; the undesired signal of the representation of the analog radio frequency signal interferes with a representation of modulation information of at least one of the plurality of independently modulated signals in an output of the digitizer, and the modified representation of the analog radio frequency signal with a diminished representation of the undesired signal does not interfere with a representation of modulation information of at least one of the plurality of independently modulated signals in the output of the digitizer. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A signal processor, comprising:
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a subtractor configured to receive an interference subtraction signal and a representation of an analog radio frequency signal having (a) an interferor, (b) a modulated information signal in a band having a bandwidth of at least 10 MHz and a frequency of at least 500 MHz, and (c) an intermodulation distortion product derived from the interferor having spurs within the band, to produce a subtractor output representing a combination of the analog radio frequency signal and the subtraction signal, having a ratio of the spurs within the band to the modulated information signal decreased by at least 20 dB; a digital signal generator, configured to produce the interference subtraction signal, comprising a synchronized representation of the interferor; and a digitizer having an instantaneous bandwidth of at least 10 MHz, configured to produce a digitized representation of the subtractor output.
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Specification