again becomes so large in the next stage or in one of the next stages that a reliable decision 34 positive 34 or 34 negative 34 is possible decision errors concerning the sign of z i 39 due to the ambiguity region u would therefore be impossible the iteration stages not implemented given a 34 zero decision 34 would then however also have to be taken into consideration in the calculation of correction factor k instead of a simple multiplication of the outputs x n and y n by the constant correction factor k an extremely involved multiplier logic would therefore have to be introduced in order to obtain a correction factor k that is constant for all rotational angles z o the 34 zero decision 34 can be replaced by a doubling of all iteration stages when due to the ambiguity region u an incorrect decision concerning the sign is made in an angle iteration stage for example the stage iz 1a then the amount of the residual angle is enlarged instead of being reduced in the following double up angle iteration stage for example iz 1b a reliable sign decision is then guaranteed so that the preceding iteration step is in turn canceled the result across two stages then corresponds to the result of one stage having a 34 zero decision 34 with a difference that all stages are always executed and the factor k therefore remains constant for arbitrary input angles z o this solution however leads to a considerable added expense for hardware due.