New active RC-networks for the generation and detection of single-sideband signals

A class of polyphase active coupled networks for quadrature signal generation is presented. These networks employ resistors, lowprecision capacitors, and commercial integrated operational amplifiers. The sequence discrimination approach implemented in the analysis of these networks is very promising in single-sideband (SSB) generation and detection. It has the advantage of achieving both frequency translation and filtering in a single step. Consequently, the iteration problems associated with active filters at high frequencies are solved. It is shown that by applying feedback between the input and output terminals of these networks, both the gain and phase sensitivities to the component variations are improved. The performance of the proposed networks is analyzed and compared to that of the well-established all-pass realization. The superiority of the proposed networks, due to their relative insensitivity to the component variations, in comparison with the all-pass technique is also verified experimentally.