Northrop Grumman Systems Corporation

Max Earl Nielsen

Joshua A Strong

Alexander Louis Braun

Haitao O Dai

Kurt Pleim

Charles Ryan Wallace

Daniel George Dosch

Bouchaib Cherif

Vladimir Vladimirovich Talanov

Jose M Acevdeo

Alexander K Sirota

Temitope Olumuyiwa Ogunnika

Peter John Andrews

Phillip Henry Fischer

Robert John March, Iii

Vladimir V Talanov

Phase detectors are provided. In one example, The phase detector may include a first transistor leg and a second transistor leg. Each of the first transistor leg and the second transistor leg may include a pair of transistors coupled together at a plurality of common nodes. The phase detector may include an input at the first transistor leg. The input may be configured to receive a first input signal and a second input signal. The phase detect may include an output coupled to the second transistor leg. The output may be configured to provide an output signal. The output signal may include a component indicative of a phase difference between the first input signal and the second input signal.

Low power phase detector

An output-amplifier-based reciprocal quantum logic (RQL) bias-level sensor is used to measure and/or calibrate bias parameters of AC and/or DC bias signals provided to RQL circuitry. The bias signals can include an output amplifier output bias current. The bias-level sensor includes a stack of DC SQUIDs that are supplied their inputs from outputs of respective Josephson transmission lines (JTLs) to which the SQUIDs are transformer-coupled. Staging relative strengths of the bias taps of the JTLs, or the critical currents of the Josephson junctions in the DC SQUIDs, allows an output voltage signal of the bias-level sensor to be indicative of whether a provided bias value is an improvement or optimization of the bias value when varied over a range. The outputs of two such bias-level sensors driven by I and Q clocks can be compared to adjust AC bias amplitudes of the clocks. Relative clock phase can be similarly adjusted.

Squid stack pulse height bias-level sensor for reciprocal quantum logic

Pulse-generator-based reciprocal quantum logic (RQL) bias-level sensors are fabricated on an RQL integrated circuit (IC) to sample AC or DC bias values provided to operational RQL circuitry on the RQL IC. The bias-level sensors include pulse generators having strengthened or weakened bias taps (transformer couplings to RQL AC clock resonators or DC bias lines) as compared to bias taps of Josephson transmission lines in the operational RQL circuitry, or Josephson junctions (JJs) with larger or smaller critical currents as compared to JJs in the operational RQL circuitry. Pulse generators with weakened bias taps or larger JJs can have lower limits of their operational ranges placed near an optimal bias point at the centroid of the operating region of the operational RQL circuitry. The bias-level sensors can be staged by relative strength to indicate whether a provided bias value is an improvement when varied over a range.

Pulse-generator-based bias-level sensors for reciprocal quantum logic

Shift register elements of a phase-mode bit-addressable sensing register sample varied AC or DC bias values provided to operational RQL circuitry on the RQL IC via clock resonators or DC bias lines. The shift register can be constructed of phase-mode D flip-flops and JTLs as data and clock lines. A method of using the sensing register includes shifting in a data bit pattern while a bias parameter (e.g., AC amplitude, DC value, or phase) is set to a nominal value; stopping the logical clock that controls the shifting of values through the sensing register, varying the bias parameter value, inputting one assertion SFQ pulse or reciprocal pulse pair into the logical clock, restoring the bias parameter to the nominal value, restarting the logical clock to shift out an output data bit pattern, and observing the output data bit pattern to determine the effect of the bias parameter value change.

Phase-mode bit-addressable sensing register

One example includes a clock distribution system. The system includes a resonator feed network comprising a plurality of resonant transmission lines that each propagate a clock signal. The system also includes at least one resonator spine. Each of the at least one resonator spine can be conductively coupled to at least one of the resonant transmission lines, such that each of the at least one resonator spine propagates the clock signal. The system further includes at least one resonator rib conductively coupled to at least one of the at least one resonator spine. Each of the at least one resonator rib can be arranged as a standing wave resonator to propagate the clock signal.

Clock distribution system

One example includes a clock distribution resonator system. The system includes a clock source configured to generate a clock signal having a predefined wavelength. The system also includes a plurality of transmission line branches each coupled to the clock source to propagate the clock signal. The system also includes a plurality of clock distribution networks coupled to the respective plurality of transmission line branches and being configured to provide the clock signal to each of a plurality of circuits. The system further includes at least one damping resonator. Each of the at least one damping resonator can be coupled to a respective at least one of the transmission line branches and configured to propagate the clock signal. The at least one damping resonator can have at least one resonator characteristic that is different relative to a respective resonator characteristic(s) associated with the transmission line branches and/or the clock distribution networks.

Clock distribution resonator system

One embodiment includes a clock distribution system. The system includes at least one resonator spine that propagates a clock signal and at least one resonator rib conductively coupled to the at least one resonator spine and being arranged as a standing wave resonator. At least one of the at least one resonator rib has a thickness that varies along a length of the respective one of the at least one resonator rib. The system also includes at least one transformer-coupling line. Each of the at least one transformer-coupling line can be conductively coupled to an associated circuit and being inductively coupled to the at least one resonator rib to inductively generate a clock current corresponding to the clock signal to provide functions for the associated circuit.

One embodiment includes a clock distribution system. The system includes at least one resonator spine that propagates a sinusoidal clock signal and at least one resonator rib conductively coupled to the at least one resonator spine and arranged as a standing wave resonator. The system further includes at least one coupling capacitor. Each of the at least one coupling capacitor can interconnect at least one of the at least one resonator rib and a respective circuit to capacitively provide a clock current corresponding to the sinusoidal clock signal to the respective circuit to provide functions for the respective circuit.

Capacitive clock distribution system

One embodiment includes a clock distribution resonator system. The system includes a clock source configured to generate a clock signal having a predefined wavelength, and a main transmission line coupled to the clock source to propagate the clock signal and comprising a first predetermined length defined as a function of the wavelength of the clock signal. The system also includes a plurality of transmission line branches each coupled to the main transmission line to propagate the clock signal. Each of the plurality of transmission line branches includes a second predetermined length different from the first predetermined length. The system further includes a plurality of clock distribution networks coupled to the respective plurality of transmission line branches and being configured to provide the clock signal to each of a plurality of circuits to provide clock synchronization for the associated plurality of circuits.

One embodiment includes a clock distribution system. The system includes at least one resonator spine that propagates a sinusoidal clock signal and at least one resonator rib conductively coupled to the at least one resonator spine and arranged as a standing wave resonator. The system also includes at least one transformer-coupling line. Each of the at least one transformer-coupling line is conductively coupled to an associated circuit and has a plurality of inductive couplings to the at least one resonator rib to inductively generate a clock current corresponding to the sinusoidal clock signal via each of the plurality of inductive couplings in an additive manner to provide functions for the associated circuit.

One embodiment includes a clock distribution system. The system includes a first resonator spine that propagates a first clock signal and a second resonator spine that propagates a second clock signal that is out-of-phase relative to the first clock signal. The system also includes at least one resonator rib each conductively coupled to at least one of the first and second resonator spines and being arranged as a standing wave resonator with respect to a respective at least one of the first and second clock signals to inductively provide the respective at least one of the first and second clock signals to an associated circuit via a respective transformer-coupling line. The system further includes an isolation element configured to mitigate at least one of inductive and capacitive coupling between the first and second clock signals.

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Odenton, MD, United States of America

Max Earl Nielsen