238 results about "Approximation error" patented technology

An RMS-to-DC converter implements the difference-of-squares function by utilizing two identical squaring cells operating in opposition to generate two signals. An error amplifier nulls the difference between the signals. When used in a measurement mode, one of the squaring cells receives the signal to be measured, and the output of the error amplifier, which provides a measure of the RMS value of the input signal, is connected to the input of the second squaring cell, thereby closing the feedback loop around the second squaring cell. When used in a control mode, a set-point signal is applied to the second squaring cell, and the output of the error amplifier is used to control a variable-gain device such as a power amplifier which provides the input to the first squaring cell, thereby closing the feedback loop around the first squaring cell. Accurate square law approximation at microwave frequencies can be achieved by implementing the squaring cells as series-connected three-transistor multi-tanh transconductance cells. By using carefully balanced squaring cells and a well-balanced error amplifier, approximation errors are cancelled and accurate RMS measurement is realized at high frequencies. A feedforward bootstrapping feature uses an op amp to balance the voltages at the common nodes of the transconductance squaring cells and also provides a balanced differential input drive to one of the squaring cells. A base current compensation circuit for providing accurate base compensation current to both of the squaring cells prevents errors due to DC offset voltages.

Systems and methods for generating check node updates in the decoding of low-density parity-check (LDPC) codes use new approximations in order to reduce the complexity of implementing a LDPC decoder, while maintaining accuracy. The new approximations approximate the standard sum-product algorithm (SPA), and can reduce the approximation error of min-sum algorithm (MSA) and have almost the same performance as sum-product algorithm (SPA) under both floating precision operation and fixed-point operation.

A regional progressive mesh provides support for real-time rendering of large-scale surfaces with locally adapting surface geometric complexity according to changing view parameters. The regional progressive mesh is constructed by subdividing an initial detailed mesh one or more times into multiple sub-regions as an iterative or recursive process. Each sub-region is separately simplified, and the localized transformations recorded in separate segments in a sequence of mesh refinement transformations that form the progressive mesh representation. The resulting regionalized organization of mesh refinement transformations reduces the working set of memory pages containing progressive mesh data needed for real-time view-dependent adaptation and rendering of the mesh surface. An exact approximate error measurement of a vertex split transformation also is defined as the maximum height deviation at enumerated vertices in the open neighborhood of the transformation relative to a regular triangulation of grid points, where the enumerated vertices include the grid points internal to the faces adjacent the split vertex and the grid line crossings internal to edges adjacent the split vertex.

A trajectory planning method according to the present invention is one for obtaining a trajectory for controlling a state of an object toward a goal state by a trajectory planning system. The method includes the steps of dividing, by a cell generating section for dividing a state space of the object into cells, the state space into cells in such a way that approximation error due to discretization is minimized for a predetermined number of cells; generating, by a search tree generating section, a search tree which corresponds to state transition of the object in such a way that each cell does not contain more than one of nodes of branches of the search tree; and determining, by a trajectory generating section, a path from the current state to the goal state of the object using the search tree.

Systems and methods are provided for optimizing a parametrization scheme in accordance with information about the surface signal. A surface parametrization is created to store a given surface signal into a texture image. The signal-specialized metric of the invention minimizes signal approximation error, i.e., the difference between the original surface signal and its reconstruction from the sampled texture. A signal-stretch parametrization metric is derived based on a Taylor expansion of signal error. For fast evaluation, the metric of the invention is pre-integrated over the surface as a metric tensor. The resulting parametrizations have increased texture resolution in surface regions with greater signal detail. Compared to traditional geometric parametrizations, the number of texture samples can often be reduced by a significant factor for a desired signal accuracy.