Showing papers on "Inverse trigonometric functions published in 1982"

A direct relation between a signal time series and its unwrapped phase

Abstract: A noniterative method for phase unwrapping a real, finite-length, discrete-time signal is described. We use an operator which counts sign changes in a Sturm sequence generated from the real and imaginary parts of the DFT. The number of sign changes is related to the number of multiples of π which must be added to the principal value arctan to produce unwrapped phase. Except for the evaluation of trigonometric and inverse trigonometric functions, the unwrapped phase at any frequency can be computed in a finite number of steps. The approach is illustrated with an example, and a Fortran program implementation of the algorithm is included in the Appendix.

Approximation of periodic functions of several variables with bounded mixed difference

Abstract: This paper studies questions concerning the approximation of functions of several variables by trigonometric polynomials whose harmonics lie in a "hyperbolic cross" and also properties of functions which do not have harmonics lying in a "hyperbolic cross." Analogues of H. Bohr's inequality are obtained for such functions. Estimates of optimal order are obtained for the upper bounds of best approximations of certain classes of functions, defined using mixed differences, by trigonometric polynomials whose harmonics lie in a "hyperbolic cross." The diameters of certain classes are found.Bibliography: 13 titles.

Flap position measuring tool

Abstract: A flap position measuring system (Figure 4) including three servo inclinometers (20, 22, 24) for providing a voltage proportional to the sine of the tilt angle. The flap position measuring system (Figure 4) provides the inverse sine of the voltage proportional to the sine of the tilt angle and displays the relative angle in degrees on a digital readout utilization device (100). The inverse sine of the voltage is provided through signal processing including analog circuitry (54, 56)( utilizing the first two terms of the Taylor series expansion of Sin-1x.

The theory of inverse boundary problems for analytic functions and its applications

Abstract: Questions of the well-posedness of inverse boundary problems on the plane and on Riemann surfaces, results on the univalent solvability of inverse boundary problems and on the corresponding parts of the geometric theory of functions of a complex variable, various inverse problems of hydroaeromechanics, and also inverse problems of pressured and unpressured filtration, mathematical and applied aspects of inverse problems on change of contours are presented.

A universal trigonometric function generator

Abstract: A synthesis principle applied to a monolithic circuit capable of generating trigonometric functions (sine, cosine, tangent, cosecant, secant and cotangent, plus arctangent) will be Presented. Analog inputs represent angle and amplitude. Law conformance is as close as ∓ 0.02%.