Analysis of mismatch impact on image rejection ratio for passive polyphase filters

Passive polyphase filters (PPFs) are useful symmetric RC networks for processing analog quadrature signals. Passive polyphase filters are also used to implement differential-quadrature or quadrature-differential converters. The quality of these quadrature signals is essential to achieve good performance in modern communication systems. However, mismatch effects can produce notable degradation in the PPF frequency response, and this results in an important reduction in quadrature signal quality, being amplitude balance and phase offset notably affected. Both these errors could be summarized and evaluated together considering image rejection ratio as a figure of merit. This work deepens in the analysis of mismatch impact on PPF, studying image rejection ratio degradation for 2 PPF types, and a systematic method is proposed to obtain the worst case of mismatch in PPFs with any number of stages. It has been validated in a 65-nm CMOS technology

Analysis of time delay difference due to parametric mismatch in matched filter channels

This paper presents an analysis of the time delay difference between the outputs of two matched filter channels, in the presence of parametric mismatch. A theorem for computing the cross-correlation value between two signals is developed. From the cross-correlation theorem, expressions are developed that estimate the effect of parametric mismatch in the differential time delay (DTD) for filters of arbitrary type and order and input signals of arbitrary form. The accuracy of these expressions is simulated and then demonstrated experimentally using a carefully designed setup. Filter design considerations that attempt to minimize spurious DTD in high-precision time delay estimation systems are presented.Fil: Julian, Pedro Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación en Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; ArgentinaFil: Stuarts, Guillermo Héctor. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación en Ingeniería Eléctrica; Argentin