Physical Devices, LLC

North Carolina State University

Charley Theodore Wilson, Iii

Frederick Vosburgh

Brian Allan Floyd

Jonathan Ryan Wilkerson

Jeffrey Franklin Bonner-Stewart

Tunable filters, cancellers, and duplexers based on passive mixers. A tunable delay cell includes passive mixers electrically coupled together for receiving an input signal and outputting a delayed signal, each passive mixer comprising a plurality of mixer switches. The tunable delay includes a control circuit for providing, to each passive mixer, a respective plurality of local oscillator (LO) signals, one to each mixer switch of each passive mixer. The control circuit is configured to vary the LO signals to cause a target frequency band of the input signal to be delayed by a target delay time in propagating through the passive mixers.

Tunable filters, cancellers, and duplexers based on passive mixers

Methods, systems, and computer readable media for a tunable filter employing feedforward cancellation are disclosed. According to one aspect, the subject matter described herein includes a tunable transmissive filter that includes a splitter for splitting an input signal into a first signal and a second signal, a first modifier circuit for modifying a characteristic of the first signal to produce a modified first signal, a second modifier circuit for using feedforward cancellation to modify a characteristic of the second signal to produce a modified second signal, the second modifier circuit including an N-path filter, N being an integer greater than 0; and a combiner for combining the modified first signal and the modified second signal to produce a filtered output signal having a bandpass response.

Tunable filter employing feedforward cancellation

Methods, systems, and computer readable media for mitigation of interference of GPS signals are disclosed providing selective mitigation of in-band interference implementing deterministic phase control. In one embodiment, a system for mitigating interference of GPS signals includes a pair of antennas, each receiving GPS signals that include both a desired signal component and a jammer signal component. The signal from one antenna is phase-shifted as needed to make it anti-phase with the signal from the other antenna, so that when the two signals are combined, the jammer signal components substantially cancel each other, leaving the desired signal components. Determining the phase shift required involves deterministically calculating the phase shift based on the amplitudes of the two input signals and the amplitude of the combined signal instead of the iterative techniques used in conventional systems.

Methods, systems, and computer readable media for mitigation of in-band interference of global positioning system (GPS) signals

Methods, systems, and computer readable media for wideband frequency and bandwidth tunable filtering are disclosed. According to one aspect, the subject matter described herein includes a wideband frequency and bandwidth tunable filter that splits a filter input signal into first and second input signals, modifies the first input signal to produce a first output signal, modifies the second input signal to produce a second output signal having an intermediate frequency response, and combines the first and second output signals while adjusting their relative phases and/or amplitudes to produce a filter output signal with the target frequency response. Adjustment includes splitting the second input signal into third and fourth input signals, which are modified and then combined to produce the second output signal having the intermediate frequency response.

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Raleigh, NC, United States of America

Charley Theodore Wilson, Iii