摘要:
A filter circuit enhances a deficient Q-value in a filter stage and buffers the filter stage from subsequent filter stages using a common active device. A filter circuit includes a first buffered filtering stage including a first Q-deficient filter stage to receive an input signal and a first Q-enhancement buffer stage. The first Q-enhancement buffer stage is coupled to the first Q-deficient filter stage, wherein the first Q-enhancement buffer stage includes a single active device to increase a Q-value of the first Q-deficient filter stage and isolate the first Q-deficient filter stage from any subsequent filter stage. A filtering method includes filtering an input signal in a first Q-deficient filter stage and enhancing a deficient Q-value of the first Q-deficient filter stage with an active device. The method further includes buffering the first Q-deficient filter stage from any subsequent filter stage with the active device.
摘要:
A screwdriver assembly includes a detachable handle, a fixed non-rotatable socket and a dual ratcheting socket extending transverse to the axis of the handle to the screwdriver with the dual sockets to obtain reversal of the screwdriver rotation.
摘要:
Techniques for correcting for memory effects of a transmitter are described. In an exemplary design, a receiver obtains input samples including a desired signal transmitted by a transmitter having memory effects. The receiver performs nonlinear equalization on the input samples to obtain first equalized samples, performs linear equalization on the input samples to obtain second equalized samples, and determines output samples based on the first and second equalized samples. The nonlinear equalization corrects for the memory effects and nonlinearities of the transmitter and possibly nonlinearities and memory effects of the receiver. The receiver may jointly determine coefficients for both linear and nonlinear equalization based on an adaptive algorithm. The receiver processes (e.g., demodulates and decodes) the output samples to recover data sent in the desired signal by the transmitter.
摘要:
A novel mobile unit which communicates with a new and advantageous base station. The mobile unit includes a system for generation of position information and a transceiver for transmitting the position information. In the preferred embodiment, the transceiver is a CDMA system and the system for generating position information includes an arrangement for receiving a GPS signal. In the preferred embodiment, a GPS assisted arrangement is employed which is adapted to receive a signal from an airborne platform as well as from a satellite based platform. The inventive base station is adapted to receive position information from a remote unit and provide a received position signal in response thereto. The novel base station is further equipped with a mechanism for directing a beam in response to the received position signal. In the illustrative embodiment, the mechanism for directing the beam is a smart antenna system including an antenna array and a beamforming network for driving the array to output the directed beam.
摘要:
A “time multiplexed” transmission scheme capable of reducing the amount of interference from other cells operated at the same frequency band. Each cell in a system transmits in designated time intervals (e.g., time slots) during which other interfering cells may be prevented from transmitting. By temporarily “blanking” transmissions from interfering cells during the designated time slots, the amount of interference from these cells is reduced. The improved signal quality may support transmission at a desired or higher data rate, which may not be possible without cell blanking. In one variant, transmissions from the cells are staggered over different time slots. A set of one or more cells may be designated to transmit in each of a number of slot phases. The cells transmit in a staggered manner on these phases to reduce interference. The transmission scheme may be used for a various channel types (e.g., a control channel) and applications.
摘要:
In a CDMA data communication system capable of variable rate transmission, utilization of beam switching techniques decreases the average interference caused by transmissions of a base station to subscriber stations within a cell, and in neighboring cells. Base stations utilize multiple transmit antennas, each transmitting signals at controlled amplitudes and phases, to form transmit signal corresponding to sector divisions. Data and reference signals are transmitted along sector division beams that alternate according to fixed time slots in order to increase system capacity and data rates by maximizing carrier-to-interference ratios (C/I) measured at subscriber stations.
摘要:
In a CDMA data communication system capable of variable rate transmission, utilization of beam switching techniques decreases the average interference caused by transmissions of a base station to subscriber stations within a cell, and in neighboring cells. Base stations utilize multiple transmit antennas, each transmitting signals at controlled amplitudes and phases, to form transmit signal corresponding to sector divisions. Data and reference signals are transmitted along sector division beams that alternate according to fixed time slots in order to increase system capacity and data rates by maximizing carrier-to-interference ratios (C/I) measured at subscriber stations.