System and method for digital interference cancellation
AssigneeHypres, Inc.
InventorsDeepnarayan Gupta, Amol Inamdar
Life of this patent
Estimating the term…
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.
Claims20
A receiver comprising:
- a saturable component, configured to receive a signal having an amplitude, and to process the signal if the amplitude is below a threshold, and being subject to saturation if the received signal is above a threshold;
- an input configured to receive an analog radio frequency input signal within a radio frequency band comprising a modulated signal and an interfering signal, the interfering signal having an amplitude sufficient to exceed the threshold and saturate the saturable component;
- a signal generator, configured to generate a nulling analog radio frequency signal which tracks a phase of the interfering signal over time;
- a subtractor, ahead of the saturable component, 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 representation of the undesired signal having an amplitude below the threshold;
- and
- an output of the saturable component which corresponds to the modulated signal without saturation interference by the interfering signal.
A method of receiving a signal using a demodulator having an instantaneous bandwidth of at least 10 MHz and a maximum dynamic range of a received signal for effectively demodulating information of a modulated signal, comprising:
- receiving an analog radio frequency input signal within a radio frequency band having a bandwidth of at least 10 MHz, comprising a modulated signal and an interfering signal, the interfering signal causing a dynamic range of the analog radio frequency input signal to be greater than the maximum dynamic range of the demodulator;
- generating a nulling analog radio frequency signal which tracks a phase and amplitude of the interfering signal;
- producing a modified representation of the analog radio frequency input signal dependent on the analog radio frequency signal and the nulling signal, with a diminished amplitude of the interfering signal, such that the dynamic range of the modified representation of the analog radio frequency input signal has a dynamic range lower than the maximum dynamic range of the demodulator;
- and
- demodulating the modified representation of the analog radio frequency signal with a diminished representation of the interfering signal using the demodulator having an instantaneous bandwidth of at least 10 MHz.
A signal processor, comprising:
- a canceller configured to receive an interference cancelling 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 of the interferor, having spurs present within the band, to produce a canceller output representing a difference of the analog radio frequency signal and the cancelling signal, having a ratio of the spurs present within the band to the modulated information signal decreased by at least 20 dB, wherein the interferor is not limited to being within the band;
- a cancelling signal generator, configured to produce the interference cancelling signal, comprising a time synchronized amplitude corresponding representation of the interferor;
- and
- a signal processing element having a maximum dynamic range, and an instantaneous bandwidth of at least 10 MHz, configured process the subtractor output, and demodulate information from the modulated information signal when the maximum dynamic range is not exceeded,
- wherein the digital canceling signal generator is configured to produce the interference cancelling signal having an amplitude sufficient, absent a corresponding interferor to cancel, to exceed the maximum dynamic range.
Dependencies are inferred from the claim text.