2054 results about "Reflection coefficient" patented technology

A high-frequency power supply system includes an anomaly detector 3 which detects an anomaly occurring in a circuit on the side of a load L as from an outputting end A of a high-frequency power source 1. The anomaly detector 3 includes a first detector 21 which detects a voltage value Vf of a high-frequency forward wave, a second detector 22 which detects a voltage value Vr of a high-frequency reflected wave, a reflection coefficient calculator 23 and a differentiator 24 which calculate a reflection coefficient differential value dΓ/dt from the forward wave voltage value Vf and the reflected wave voltage value Vr, and an anomaly determiner 25 which determines of an occurrence of an anomaly based on the reflection coefficient differential value dΓ/dt. When the anomaly detector 3 outputs an anomaly detection signal to the high-frequency power source 1, high-frequency power source 1 stops its power output operation.

A wireless mobile terminal includes an antenna, a power amplifier coupled to the antenna, a power detector coupled to an output of the power amplifier, a phase shifter coupled between the output of the power amplifier and the antenna, and a controller coupled to the phase shifter. The power detector is configured to detect a power of a signal provided by the power amplifier. The controller is configured to adjust the phase shifter responsive to the detected signal power. More particularly, the controller may be configured to adjust the phase shifter to modify a phase component of a reflection coefficient of a load impedance at the power amplifier output without substantially altering a magnitude of the reflection coefficient. Related methods and computer program products are also discussed.

A transceiver front end circuit includes an antenna terminal capable of being coupled to an antenna. A first balun circuit has a single input that is coupled to the antenna terminal, and a pair of balanced outputs coupled to a corresponding pair of balanced receiver inputs. The first balun circuit matches an input impedance of the pair of balanced receiver inputs and substantially phase shifts the input reflection coefficient of the pair of balanced receiver inputs by about 180-degrees. A second balun circuit has a single output coupled to the antenna terminal and a pair of balanced inputs coupled to a corresponding pair of balanced transmitter outputs. The second balun circuit matches an output impedance of the pair of balanced transmitter outputs and substantially phase shifts the output reflection coefficient of the pair of balanced transmitter outputs by about 180-degrees. The first balun circuit and the second balun circuit can be contained within a single package. A first shunt switch can be coupled across the pair of receiver inputs. A second shunt switch can be coupled across the pair of transmitter outputs.

Classifying a portion of an electrical signal propagating through a conductor includes digitizing the electrical signal to provide a digitized signal, providing a plurality of stored digitized signals, wherein each stored digitized signal corresponds to a type of fault for the conductor, comparing the digitized signal to each of the stored digitized signals to determine a score therefore, if the score is less than a predetermined value for a particular one of the stored digitized signals, classifying the portion of the electrical signal as a fault corresponding to the particular one of the stored digitized signals, and, if none of the scores are less than the predetermined value, classifying the portion of the electrical signal as having no fault. Classifying a portion of an electrical signal may also include converting the digitized electrical signal to reflection coefficients.

The present invention is an adaptable pre-matched tuner system and calibration method for measuring reflection factors above Gamma=0.85 for a DUT. The system includes a first and second large-band microwave tuners connected in series, the first and second large-band tuners being mechanically and electronically integrated; and a controller for controlling the two large-band tuners. The first tuner is adapted to act as a pre-matching tuner and the second tuner is adapted to investigate an area of a Smith Chart that is difficult to characterise with a single tuner, so that the combination of the first and second large-band tuners permits the measurement of reflection factors above Gamma=0.85. The pre-matched tuner system allows the generation of a very high reflection factor at any point of the reflection factor plane (Smith Chart). The pre-matched tuner must be properly calibrated, such as to be able to concentrate the search for optimum performance of the DUT in the exact location of the reflection factor plane where the DUT performs best, using a pre-search algorithm.

An up-going wavefield and a down-going wavefield are calculated at a sensor position from a pressure sensor signal and a particle motion sensor signal. Then, an up-going wavefield is calculated at a water bottom position substantially without water bottom multiples from the up-going and down-going wavefields at the sensor position. In one embodiment, the up-going wavefield at the sensor position is backward propagated to the water bottom, resulting in an up-going wavefield at the water bottom. The down-going wavefield at the sensor position is forward propagated to the water bottom, resulting in a down-going wavefield at the water bottom. The up-going wavefield at the water bottom without water bottom multiples is calculated from the backward propagated up-going wavefield at the water bottom, the forward propagated down-going wavefield at the water bottom, and a reflection coefficient of the water bottom.

The invention relates to a detection method of standing-wave ratio of a time division duplex communication system, which comprises the following steps: a forward signal is sampled by switching a switch at a time interval of standing-wave ratio measurement; a reverse signal is sampled by switching the switch at the next time interval of standing-wave ratio measurement; the forward and the reverse signals is coupled and delivered to a digital-to-analog converter through a coupling passage, the delivered signal is sampled and quantized by using an AD sampler and processed by means of digital down-conversion to obtain a sampled data of baseband; a reflection coefficient |gamma_AD| is obtained by calculating, the transmission characteristic difference CF_R(Omega 0) between a forward detection channel and a reverse detection channel is obtained at the current frequency after table lookup process; and the standing-wave ratio VSWR is calculated based on the reflection coefficient |gamma_AD| and the transmission characteristic difference CF_R(Omega 0). Therefore, the invention realizes the multiplexing of a normal reception channel and the reverse and the forward standing-wave ratio channels, enables the normal reception channel to be used in standing-wave ratio detection, and ensures the equivalency of front/reverse power samplings by measuring the front and the reverse powers of the pilot frequency.

A method for modeling optical scattering includes an initial step of defining a zero-th order structure (an idealized representation) for a subject including a perturbation domain and a background material. A Green's function and a zero-th order wave function are obtained for the zero-th order structure using rigorous coupled wave analysis (RCWA). A Lippmann-Schwinger equation is constructed including the Green's function, zero-th order wave function and a perturbation function. The Lippmann-Schwinger equation is then evaluated over a selected set of mesh points within the perturbation domain. The resulting linear equations are solved to compute one or more reflection coefficients for the subject.

Aspects of this invention include a downhole tool having first and second radially offset ultrasonic standoff sensors and a controller including instructions to determine at least one of a drilling fluid acoustic velocity and a drilling fluid attenuation coefficient from the reflected waveforms received at the standoff sensors. The drilling fluid acoustic velocity may be determined via processing the time delay between arrivals of a predetermined wellbore reflection component at the first and second sensors. The drilling fluid attenuation coefficient may be determined via processing amplitudes of the predetermined wellbore reflection coefficients. The invention advantageously enables the acoustic velocity and attenuation coefficient of drilling fluid in the borehole annulus to be determined in substantially real-time.

In order to make a reflection coefficient in boundary surface between materials to be zero and permeate 100% of a light independent of a polarization direction, an optical device made of an optical material composed of a metamaterial prepared by arranging a plurality of at least either of electrical resonators or magnetic resonators each being smaller than a wavelength of a light wave in only a predetermined plane, and at least either of the electrical resonators and the magnetic resonators arranged functioning with respect to s-polarization, whereby at least either of the dielectric constant or the magnetic permeability is controlled in response to the function to induce a Brewster phenomenon in the s-polarization wherein the incident plane of a light wave being set out at a Brewster's angle with respect to the p-polarization and further at least either of the dielectric constant and the magnetic permeability of the optical material being controlled with respect to the s-polarization of the optical material, whereby the Brewster condition is independently satisfied in both the p-polarization and the s-polarization at the same time.

Real-time calibration of a tunable matching network that matches the dynamic impedance of an antenna in a radio frequency receiver system. The radio frequency receiver system includes two non-linear equations that may be solved to determine the reflection coefficient of the antenna. The tunable matching network is repeatedly perturbed and the power received by the antenna is measured after each perturbation at the same node in the matching network. The measured power values are used by an optimizer in converging to a solution that provides the reflection coefficient of the antenna. The reflection coefficient of the antenna may be used to determine the input impedance of the antenna. The elements of the matching circuit are then adjusted to match the input impedance of the antenna.

The invention provides increased structural monitoring systems that have sensitive continuous coaxial cable sensors. A preferred embodiment sensor cable of the invention includes an inner conductor, a dielectric jacket, and an outer conductor that is configured to passively deform responsively to strain in an associated structure. The deformation can be aided by the physical structure of the dielectric jacket, the outer conductor, or a combination of both. The deformation translates strain into a measurable change in a reflection coefficient associated with the outer conductor.

A calibration system is provided for calibrating frequency domain reflectometers in the field by using both the scattering parameters of the multi-port junction determined at the factory and changing the offset and gain terms used in generating a complex reflection coefficient by using internal calibrated loads so that heavy, cumbersome external calibrated transmission lines are not required. In one embodiment the internal calibrated loads include RLC circuits and in another embodiment the internal calibrated loads include attenuators. Further, retesting or recalibration does not necessitate reconnecting the cable under test, which may remain connected to the reflectometer's test port throughout the procedure.

An apparatus and method for measuring coefficients of retroreflectance of retroreflective surfaces such as road signs involves use of a modified light based range finder. The apparatus includes a power attenuation factor data base which relates pulse width of received pulses to power attenuation of the transmitted pulses. The range finder calculates target range based on time of flight of light pulses. The apparatus automatically calculates the absolute coefficient of retroreflectance for an unknown reflective surface being measured by comparison of the measurement to a reading with the same instrument of a known reflectance standard. The method involves either recalling a stored standard reference reflectance factor or determining a reflectance factor via the range finder for a sample of retroreflective material with a predetermined coefficient of retroreflectance, and then measuring the distance to an unknown target, determining a power attenuation factor from the received pulse width from the unknown target and then calculating the absolute coefficient of retroreflectance based upon these determined values of power attenuation factor, distance and the reference reflectance factor.