Massachusetts Institute of Technology

Merck Sharp + Dohme Corp.

Benjamin A Miller

Joel Irwin Goodman

Helen Haeran Kim

Andrew K Bolstad

James Edwin Vian

Merlin Green

Matthew A Herman

Gurudatt Ajay Chandorkar

Daniel D Santiago

Gopal Krishna

Elham Hershberger

Karen Gettings

Alan Xiao

Mathias Kolle

Andrew Raymond Chen

Jason R Thornton

Kevin Kyung Nam

Marianne A Deangelus

Michael N Ericson

The present disclosure describes photonic materials that reversibly change color in response to the material being stretched or otherwise mechanically deformed.

Deformable photonic materials and related methods

Disclosed are methods of administering cephalosporin/tazobactam to human patients with end stage renal disease undergoing hemodialysis and suffering from a complicated intra-abdominal infection or a complicated urinary tract infection.

Treating infections with ceftolozane/tazobactam in subjects having impaired renal function

Exemplary embodiments include a system and method for Automatic Customization of Content Filtering (ACCF). The method includes receiving a search string from a user, creating a first filter based on the search string and searching different types of content stored in different content locations based on the first filter. The search returns a first subset of results to the user based on the first filter. The method further receives an indication of relevance for each one of the results in the first subset from the user. The method dynamically creates a second filter based on the received indications of relevance for the first subset of results. Based on the second filter, a second subset of more relevant results is returned to the user.

Systems and methods for automatic customization of content filtering

Receiver design techniques are provided that are capable of producing relatively efficient, linear radio frequency (RF) receivers. During a design process, components of an analog receiver chain and digital nonlinearity compensation techniques are considered together to achieve reduced power consumption in the receiver.

Analog/digital co-design methodology to achieve high linearity and low power dissipation in a radio frequency (RF) receiver

A radio frequency (RF) receiver includes an analog receiver chain followed by digital circuitry for reducing nonlinear distortion components within an output signal of the analog receiver chain. In at least one embodiment, the digital circuitry includes a digital equalizer that is configured with a sparse set of Volterra series coefficients. In this manner, a desired level of linearity performance may be achieved in the receiver with relatively low power consumption.

Method and apparatus for sparse polynomial equalization of RF receiver chains

Complex polyphase nonlinear equalizer (cpNLEQs) mitigate nonlinear distortions generated by complex in-phase/quadrature (I/Q) time-interleaved analog-to-digital converters (TIADCs). Example cpNLEQs upsample the digital waveform emitted by the TIADC, e.g., by a factor of two, then separate the upsampled digital waveform into upsampled in-phase and quadrature components. Processors in the cpNLEQs create real and imaginary nonlinear compensation terms from the upsampled in-phase and quadrature components. The nonlinear compensation terms are downsampled, and the downsampled imaginary nonlinear compensation term is phase-shifted, then combined with the downsampled real component to produce an estimated residual distortion. Subtracting the estimated residual distortion from the digital waveform emitted by the TIADC yields an equalized digital waveform suitable for further processing.

Method and apparatus for complex in-phase/quadrature polyphase nonlinear equalization

A method for digital compensation of a nonlinear system comprises identifying a plurality of circuit parameters of a nonlinear system. Each circuit parameter determines a nonlinear response of the nonlinear system. A first circuit parameter is chosen from the plurality of circuit parameters. The first circuit parameter determines a first effect on the nonlinear response. The first effect is at least as large a second effect from a second circuit parameter from the plurality of circuit parameters. At least one stimulus is applied to the nonlinear system. The nonlinear response of the nonlinear system is measured in response to the at least one stimulus. A compensation architecture is synthesized to substantially linearize the nonlinear response. The compensation architecture receives the nonlinear response of the nonlinear system and provides a substantially linear response.

Digital compensation of a nonlinear system

Polyphase nonlinear digital predistorters (pNDPs) mitigate nonlinear distortions generated by time-interleaved digital-to-analog converters (TIDACs). Processors in an example pNDP compute nonlinear and linear compensation terms representative of channel mismatches and other imperfections in the TIDAC based on the digital input to the TIDAC. The pNDP subtracts these compensation terms from a delayed copy of the digital input to yield a predistorted digital input. The TIDAC converts on the predistorted digital input into a fullband analog output that is substantially free of nonlinear distortion.

Polyphase nonlinear digital predistortion

Described is a space-time digital power amplifier that can be used to generate an arbitrary waveform for a carrier signal. The space-time digital power amplifier employs temporal modulation of transmit signals generated by an array of transmitter modules. The RF signals transmitted from the array are spatially combined through free space propagation to generate the desired waveform. Advantageously, no digital-to-analog conversion is required and upconversion is unnecessary. The digital power amplifiers for the transmitter modules can be combined in a single chip package. The space-time digital power amplifier enables high power efficiency to be realized using pulse-shaped waveforms thus eliminating any need for the power amplifiers to operate over a wider bandwidth with a spectrally unconfined waveform.

Space-time digital power amplifier

A method or corresponding apparatus relates to a mathematical approach to efficiently search for and localize regions in a multi-dimensional signal space to enable inversion of power amplifier nonlinearities with a significant reduction in computational complexity and an efficient hardware implementation. To linearize a wideband power amplifier, an example embodiment of the present invention may represent a response of the wideband power amplifier using coefficients in a cube coefficient subspace, and search over the full multi-dimensional subspace according to an optimization criterion in order to identify a vector of cube coefficient subspace coefficients. The vector of coefficient subspace coefficients may be used to linearize the wide-band power amplifier.

Growing community of inventors

Allston, MA, United States of America

Benjamin A Miller