US 12,132,446 B1Granted

System and method for phase locked loop (PLL) based removal of modulated interference

AssigneeRockwell Collins, Inc.

InventorStephen A. Ganje

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Abstract

A system and method for removing modulated interference (e.g., FSK, MSK, CW) from an input signal demodulates the input signal into a tracking bitstream via a set of phase locked loop (PLL) filters, one PLL filter for each modulated interference component (e.g., signal) known or suspected to be interfering with the input signal. Each PLL filter estimates, based on an estimated modulation frequency and center frequency associated with its target modulated interference component, a peak magnitude, phase, and updated center frequency and, based on these parameters, approximates the target interference component. Each re-created modulated interference component is subtracted from the original input signal to produce an output signal from which the known or suspected modulated interference components have been substantially removed.

Claims18

Dependent claims

A receiver system for removing modulated interference from an input signal, comprising:

a signal receiver configured for receiving an input signal comprising a modulated carrier wave interfered with by one or more modulated interference components, each modulated interference component associated with one or more modulation schemes;
and
a set of one or more phase locked loop (PLL) filters coupled to the signal receiver, each PLL filter corresponding to a modulated interference component of the one or more modulated interference components and configured to:
demodulate the input signal into a tracking bitstream;
estimate a modulation frequency and a center frequency associated with the corresponding modulated interference component;
estimate, by sampling the tracking bitstream:
a peak magnitude of the corresponding modulated interference component;
a phase of the corresponding modulated interference component;
and
an updated center frequency of the corresponding modulated interference component;
produce an estimated interference signal approximating the associated modulated interference component by re-modulating the tracking bitstream based on one or more of the modulation frequency, estimated peak magnitude, the estimated phase, the estimated center frequency, or the updated center frequency;
and
wherein the signal receiver is configured to produce an output signal by subtracting from the input signal the one or more estimated interference signals.

10 more elements

A method for removal of modulated interference signals, comprising:

receiving, via a removal engine of a signal receiver, an input signal comprising of a modulated carrier wave interfered with by one or more modulated interference components, each modulated interference component associated with one or more modulation schemes;
demodulating the input signal into a tracking bitstream via each of a set of one or more phase locked loop (PLL) filters of the removal engine, the one or more PLL filters corresponding to the one or more modulated interference components;
estimating, via each of the set of PLL filters, a modulation frequency and a center frequency associated with each corresponding modulated interference component;
sampling, via each of the set of PLL filters, the tracking bitstream to estimate:
a peak magnitude of the corresponding modulated interference component;
a phase of the corresponding modulated interference component;
and
an updated center frequency of the corresponding modulated interference component;
generating, via each of the set of PLL filters, an estimated interference signal by demodulating the tracking bitstream based on one or more of the modulation frequency, the estimated peak magnitude, the estimated phase, the estimated center frequency, or the updated center frequency;
and
producing, via the removal engine, an output signal by subtracting from the input signal the one or more estimated interference signals.

8 more elements

Dependencies are inferred from the claim text.