Showing papers on "Inverse trigonometric functions published in 1997"

A computer system performing an inverse cosine transfer function for use with multimedia information

Abstract: A computer system (100) for performing a two-dimensional inverse Discrete Cosine Transform includes multimedia input devices (125, 126), a memory (104) and a processor (109). The processor (109) implements the transform by executing SIMD mathematical and SIMD shift instructions. Shifting is used to preserve accuracy.

Inverse cosine transform method and inverse cosine transformer

Abstract: PROBLEM TO BE SOLVED: To reduce the total operation volume of inverse cosince transform operation and to attain inverse cosine transform operation even when increasing the number of pixels without sharply increasing operation frequency and arrang ing processing blocks in parallel. SOLUTION: In the case of inverse cosine transform operation for executing inverse cosine transform for the coefficient data of a two-dimensional(2D) block processed by 2D cosine transform, the positions of zero data (shown in black star mark) and non-zero data () in the 2D block of coefficient data are detected and the operation of rows R or columns C in which the coefficient data of all rows R or columns C in the 2D block are zero (space) is omitted.

Estimator of direction of desired signal

Abstract: A desired signal is received at first and second antennas. Output signals of the first and second antennas are orthogonal-detected by first and second signal conversion circuits and thereby converted into first and second baseband signals. A complex conjugation circuit generates a complex conjugation signal by calculating a complex conjugation of the second baseband signal. The first baseband signal and the complex conjugation signal are multiplied by a multiplier. A direction estimation circuit estimates a direction of the desired signal by effecting an inverse tangent calculation and an inverse cosine calculation on an output signal of the multiplier.

Block and convolutional codes decoding method for digital communication

Abstract: The method involves using a decoder comprising a nonlinear network, which is derived from the code or parity equations, in which all bit or symbols in an equation are represented by their log-likelihood values as real values. In the network, all symbols connected by code or parity equations are connected by a boxplus element, while all symbols are stored in a circuit element and represented as currents, charges, or voltages. These values can also be represented as real fixed-point or floating-point variables, e.g. in a processor or circuit. Conversion tables and nonlinearities such as tangent hyperbolic and inverse tangent hyperbolic functions are also used.

Fast convergent quasipower series for some elementary and special functions

Abstract: The aim of this paper is to prove that many functions having infinitely many poles can be expanded in quasipower series which is convergent in the whole complex plane. These new series, based on a simple general transformation, are given here for numerous elliptic (and other similar) functions, some trigonometric functions, some polygamma functions and Beta function.

Basic analog of Fourier series on a {\large $\que$}-quadratic grid

Abstract: We prove orthogonality relations for some analogs of trigonometric functions on a $q$-quadratic grid and introduce the corresponding $q$-Fourier series. We also discuss several other properties of this basic trigonometric system and the $q$-Fourier series.

Method and device for filtering a speech signal by equalisation, implemented by a statistical signal model

Abstract: The method involves using a spectral energy calculation module (10) in which a fast Fourier transform (FFT) processor (12) is followed by a filter bank (14). Typically 24 critical bands are distributed according to a non-linear scale which gives higher spectral resolution at low frequencies. A smoothed spectrum (S(f)) is forwarded to another module (16) which calculates the logarithm of the spectral energy for an inverse FFT (18). This is implemented by an inverse cosine transform and produces the cepstrum AC(n)U of the speech signal. in the form of a set of frequency-based cepstral coefficients.