Abstract: The circuit arrangement for determining an angle (.alpha.) from analog signals (C,S) proportional to the sine and cosine of the angle (.alpha.) to be determined includesa circuit device for multiplying an analog signal (S) with a digital value (Cs) for obtaining a first product value (S*Cs), the digital value (Cs) being proportional to the cosine of an estimated angle value (.alpha..sub.s) for the angle (.alpha.) to be determined;a circuit device for multiplying another analog signal (C) with another digital value (Ss) to obtain a second product value (C*Ss), the another digital value (Ss) being proportional to the sine of the estimated angle value (.alpha..sub.s) for the angle (.alpha.) to be determined;a circuit device for adding the first and second product values (S*Cs; C*Ss) to obtain a sum value (Su);a circuit device for equalizing proportionality factors of the one and/or the other digital value (Ss; Cs) so that the sum value (Su) formed is proportional to sin (.alpha.-.alpha..sub.

Abstract: A differential detection receiver with a reduced power consumption is provided by simplifying constituent circuits of the differential detection receiver. An arctangent calculator is realized without using a multiplier of a conversion table. Without using a D/A converter, a level adjusting circuit for adjusting the absolute value of a vector (Ax, Ay) given as input signals Ax and Ay so as to make it one. The power consumption of a differential detection demodulator is reduced by eliminating power consuming circuits such as a multiplier and a large conversion table from the system.

Abstract: Disclosed is a phase angle data-trigonometric function value converter circuit for computing a trigonometric function value corresponding to an angle that an angle of 360 degrees is divided into n equal parts, where n is an integer, which has: means for converting the integer n into angle data represented by binary system; a sine value data memory which stores sine values corresponding to the angle data from zero degree to 90 degrees and outputs sine values corresponding to the angle data to be input thereto; a cosine value data memory which stores cosine values corresponding to the angle data from zero degree to 90 degrees and outputs cosine values corresponding to the angle data to be input thereto; a selector to which the sine values output from the sine value data memory and the cosine values output from the cosine value memory are input and which selects the sine values or the cosine values according to the angle data and outputs them; and means for adding a polarity sign to the sine values or cosine val

Abstract: A method using replication of distributed arithmetic logic circuits and recursive interpolation of reduced angular increments of sine and cosine sum constants in logic look-up tables, permits the computation of vector rotation and large FFTs in a unitary field programmable gate array chip without required off-chip memory for storing constants.