Segment-wise approximation of envelope curve logarithm - feeding direct and delayed quadrature signals to amplitude comparator with individually variable weighting factors

摘要

Segment-wise approximation of the logarithm of the envelope of bandpass signals in differential form involves separating an input signal into a direct component and one delayed by the transition time, regulating their phase difference in a quadrature unit and feeding the direct and delayed quadrature signals to an amplitude comparison unit with individually variable comparator weighting factors. A first approximation to a section of the logarithm is formed from the phase difference arising in the amplitude comparison and the quadrature error is corrected. A null point computation is performed to improve the approximation and a systematic approximation error is derived. ADVANTAGE - Increased accuracy of approximation of logarithmic characteristics is achieved over greater dynamic range.