Low power consuming, low noise, zero-IF direct conversion receiver for digital audio system DAB

This paper describes the systematic investigation of a universal, broadband direct conversion quadrature front-end for L-band systems. Starting with a comparison of the advantages and disadvantages of homodyne and heterodyne receivers, the required components for a direct conversion system are discussed in detail. The digital broadcasting system DAB is chosen as a practical application of such a concept. The baseband low noise design concept is explained. The theoretical results are verified experimentally and compaired with the requirements of today's receivers. Especially the effects of imbalance within the quadrature front-end and the bit error ratio are investigated.