7709results about "Pulse shaping" patented technology

A wireless communication system can comprise two or more antennas that interfere with one another via free space coupling, surface wave crosstalk, dielectric leakage, or other interference effect. The interference effect can produce an interference signal on one of the antennas. A cancellation device can suppress antenna interference by generating an estimate of the interference signal and subtracting the estimate from the interference signal. The cancellation device can generate the estimate based on sampling signals on an antenna that generates the interference or on an antenna that receives the interference. The cancellation device can comprise a model of the crosstalk effect. Transmitting test signals on the communication system can define or refine the model.

A method of operating a master/slave system includes the step of identifying a master receive data phase value to coordinate the transfer of data from a slave device without phase alignment circuitry to a master device with a universal phase aligner. Data is transferred from the slave device to the master device in accordance with the master receive data phase value. The master device characterizes a master transmit data phase value to coordinate the transfer of data from the master device to the slave device. Subsequently, the master device routes data to the slave device in accordance with the master transmit data phase value.

Fabrication methods for capacitive-micromachined ultrasound transducers (“cMUT”) and cMUT imaging array systems are provided. cMUT devices fabricated from low process temperatures are also provided. In an exemplary embodiment, a process temperature can be less than approximately 300 degrees Celsius. A cMUT fabrication method generally comprises depositing and patterning materials on a substrate (400). The substrate (400) can be silicon, transparent, other materials. In an exemplary embodiment, multiple metal layers (405, 410, 415) can be deposited and patterned onto the substrate (400); several membrane layers (420, 435, 445) can be deposited over the multiple metal layers (405, 410, 415); and additional metal layers (425, 430) can be disposed within the several membrane layers (420, 435, 445). The second metal layer (410) is preferably resistant to etchants used to etch the third metal layer (415) when forming a cavity (447). Other embodiments are also claimed and described.

A wireless communication system, and method using multiple antennas, includes a base station that applies predetermined weight vectors to multi-user signals and transmits the multi-user signals through a plurality of transmission antennas, and a plurality of mobile stations that receive and process the multi-user signals, wherein each mobile station includes a signal reception unit that processes the multi-user signals, and a feedback signal generation unit that estimates channel characteristics, over which the multi-user signals have been transmitted, from the multi-user signals, classifies a plurality of weight vectors to be applied to the estimated channel characteristics into a plurality of sets such that vectors orthogonal to one another are classified into a single set, selects a set maximizing a transmission capacity from among the classified sets, and feeds back weight indexes of weight vectors included in the selected set and weighted channel information to the base station.

Systems and methods are herein disclosed for efficiently allowing current to bypass a group of solar cells having one or more malfunctioning or shaded solar cells without overwhelming a bypass diode. This can be done using a switch (e.g., a MOSFET) connected in parallel with the bypass diode. By turning the switch on and off, a majority of the bypass current can be routed through the switch, which is configured to handle larger currents than the bypass diode is designed for, leaving only a minority of the current to pass through the bypass diode.

A double-gated low power active clamp circuit for digital circuits includes a first double-gated MOSFET serially connected between an upper power supply voltage and an input terminal to be clamped, and a second double-gated MOSFET serially connected between a lower voltage power supply and the input terminal. The voltages at the gates of the first and second double-gated MOSFETs are held at constant reference voltages by a single or double reference circuits. The clamping action can be switched on or off. The double-gated active clamping network can be implemented with a single power supply voltage, or with multiple power supply voltages. The use of the back gates of the double-gated active clamping network enables additional clamping and ESD protection for smaller generations of transistors, such as, those having dimensions below 0.1 micron. The device is particularly suited for use with dynamic threshold double-gated silicon-on-insulator, FINFET, and bulk triple well technologies.

The present invention is directed to the selective provision of interference canceled signal streams to demodulating fingers in a communication receiver. According to the present invention, potential interferer signal paths are identified. Signal streams having one or more potential interferer signals removed or canceled are created, and a correlation is performed to determine whether the strength of a desired signal path increased as a result. If the correlation indicates that the strength of a desired signal path was increased by the signal cancellation, the interference canceled signal stream is provided to the demodulation finger assigned to track the desired signal path. If the correlation determines that the strength of the desired signal path did not increase as a result of performing interference cancellation, the raw or a different interference canceled signal stream is provided to the demodulation finger.

This invention describes a wireless system comprising a plurality of transmitters and receivers, wherein each transmitter has between 1 and n antennas and each receiver has between 1 and m antennas wherein one of said transmitter is arranged to transmit to one of the receivers, said one transmitter is controlled in dependence on at least one of at least one parameter of said transmitters, at least one parameter of said receiver, and at least one parameter of a wireless environment between said transmitter and said receiver.

Techniques for calculating the system characteristic of the adaptive filtering used for equalization and echo-suppression in a digital communications receiver, such as one used for receiving over-the-air broadcast digital television signal, are described. In these techniques, the system characteristic of the adaptive filtering is calculated from the discrete Fourier transform of successive portions of the input signal supplied to the adaptive filtering and from the discrete Fourier transform of corresponding portions of the transmitted signal, as estimated in the receiver. Receivers for implementing these techniques in various ways are also disclosed.

The equalizer of the present invention operates on input multipath signal samples, preferably at chip or sub-chip resolution, to remove or substantially cancel the effects of one or more secondary signals from the main path signal. Using predetermined path information for one or more of the secondary path signals, including magnitude, phase, and time offset relative to the main path signal, the equalizer compensates input multipath signal samples by subtracting estimated secondary signal values from the input samples. For each input sample, the equalizer forms a sliced sample, where the sliced sample represents a nominal phase value defined by the modulation scheme used in the original chip or symbol transmission that is closest in value to the actual phase of the input sample. These sliced samples are held in a running buffer and used, in combination with the predetermined path information and scaling logic, to form the estimated secondary signal values for compensating the input samples.

Systems and methods for providing notifications to players of a gaming console of messages and system notifications. A controller and the gaming console include a four quadrant LED indicator. Each quadrant of the ring may be illuminated individually or together using an LED to indicate the messages and notifications. The quadrants may be illuminated in one of three colors and/or in patterns to indicate different types of notifications. Onscreen displays may be used to supplement the LED indicators to convey information to users. A method of binding and discovering a controller is also provided where the controller may be bound to a gaming console. After a controller is bound to a console, the controller may be discovered by the gaming console where it is assigned a virtual port and enabled for game play.

A system and method are described for compensating for frequency and phase offsets in a multiple antenna system (MAS) with multi-user (MU) transmissions (“MU-MAS”). For example, a method according to one embodiment of the invention comprises: transmitting a training signal from each antenna of a base station to one or each of a plurality of wireless client devices, one or each of the client devices analyzing each training signal to generate frequency offset compensation data, and receiving the frequency offset compensation data at the base station; computing MU-MAS precoder weights based on the frequency offset compensation data to pre-cancel the frequency offset at the transmitter; precoding training signal using the MU-MAS precoder weights to generate precoded training signals for each antenna of the base station; transmitting the precoded training signal from each antenna of a base station to each of a plurality of wireless client devices, each of the client devices analyzing each training signal to generate channel characterization data, and receiving the channel characterization data at the base station; computing a plurality of MU-MAS precoder weights based on the channel characterization data, the MU-MAS precoder weights calculated to pre-cancel frequency and phase offset and/or inter-user interference; precoding data using the MU-MAS precoder weights to generate precoded data signals for each antenna of the base station; and transmitting the precoded data signals through each antenna of the base station to each respective client device.

A pulse-width-modulation control circuit of a switching-mode power converter with a primary-side feedback control is disclosed. The switching-mode power converter includes a transformer, a power switch, a current sensing resistor and the pulse-width-modulation control circuit. The transformer includes a primary-side winding, a secondary-side winding and an auxiliary winding. The pulse-width-modulation control circuit includes a sample and hold circuit, a transconductor circuit, an error amplifier and a pulse-width-modulation generator.

A novel and useful apparatus for and method of Gaussian Minimum Shift Keying (GMSK) single antenna interference cancellation (SAIC) for use in a digital receiver. The invention comprises an interference mitigation module that treats the problem of GMSK SAIC in a blind manner. The interference mitigation mechanism is operative to compensate for the co-channel interference added in the communications channel which is subject to multipath propagation and fading, receiver filter and any pre-channel estimation filtering. The interference mitigation module takes advantage of the spatial diversity making up multiple branches of the received signal. The branches comprise the in-phase and quadrature elements of the received signal, the sampling phases if over sampling is applied (i.e. T/m sampling) and/or multiple antennas. The invention utilizes the spatial diversity of these multiple representations of the received signal and combines (i.e. collapses) the information in the plurality of branches into a single branch that is input to the equalizer.

A delay locked loop (DLL) circuit having a structure in which a method of performing duty cycle correction (DCC) using two DLLs and an intermediate phase composer and a method of performing DCC by forming a closed loop using a negative feedback are combined with each other is provided. The DLL circuit includes a first DLL for receiving an external clock signal and generating a first clock signal and a second DLL for receiving an external clock signal and generating a second clock signal. The first clock signal and the second clock signal are synchronized with an external clock signal. The DLL circuit further includes an intermediate phase generation circuit for receiving the first and second clock signals and generating an intermediate phase clock signal and a DCC loop for receiving the intermediate phase clock signal and generating an output clock signal. The intermediate phase clock signal has an intermediate phase between the phases of the first and second clock signals. The output clock signal is generated through correction of the duty cycle of the intermediate phase clock signal using a value obtained by integrating the output clock signal.

A multistage interference canceller and method for removing interference between users and multipath interference from received signals in multiple stages includes a plurality of despreading units which produce a received symbol vector and an estimated channel value, a synthesis unit which synthesizes the received symbol vector, an amplitude of the received symbol vector and the amplitude of the estimated value from each reverse spreading unit, and a decision unit which executes a hard decision and a soft decision according to a result of comparing the total amplitude of the received symbol vector and the total amplitude of the estimated channel value.

A method and apparatus for spatial multiplexing and demultiplexing of radio signals. A multichannel transmitter and receiver is integrated in a base station and coupled to an antenna array. Using digital radio signals containing previously known or non-Gaussian sequences and arranged in frames, the spatial information about each mobile unit is estimated on the basis of the signal received by the receiver for the reception and transmission frequencies. This is done by known sequences or by blind source separation methods. The respective paths of each mobile unit with the power above a predetermined threshold is isolated by spatial filtering in the presence of multiple channel paths in order to provide spatial demultiplexing. Simultaneously, the intended signal is transmitted in the direction of the main path of each mobile unit while protecting each mobile unit from signals transmitted in the direction of other mobile units by spatial filtering with cancelling constraints in order to provide spatial multiplexing.

The present invention relates to a blind adaptive filter for narrowband interference cancellation, which includes an adaptive filter, a delay unit coupled to the adaptive filter for generating a delayed signal with a predetermined delay length from the output signal of the adaptive filter, and an error calculation unit coupled to the adaptive filter and the delay unit. The error calculation unit compares the output signal from the adaptive filter and the delayed signal from the delay unit to extract error information, and feedback the first error information to the adaptive filter. The first error information is formed of a transfer function including a number of coefficients, and used to adjust the adaptive filter and remove interference in the next input signal. The disclosed technique is also applicable in wideband receivers, as well as resisting multiple strong narrowband interferences having a frequency sweep rate of tens of milliseconds.

A communication system uses analog and digital circuits along the same data path in a manner that permits the analog circuitry to avoid adverse affects caused by the digital circuitry. Consistent with one embodiment directed to a signal processing system that detects faint incoming signals, the analog and digital circuits are implemented on a single piece of silicon. In such signal processing systems, noise generated by digital processing blocks can degrade the performance of sensitive analog portions. The effective noise is reduced by causing the analog and digital portions of the system to function during separate time intervals. The noise-generating portions of the system may then be turned off during a first data-communication interval while the analog block operates. The data acquired during this period is stored for subsequent processing by the digital portion during a second shorter data-communication interval. Other aspects are applicable to reception arrangements in which part of the incoming signal may be disregarded without significant degradation in performance of the rest of the system, and other aspects are directed to transmission arrangements in which the inverse of the above reception arrangement is used.