De-interleaved direct down-conversion receiver for SDR applications

This paper proposes a low complexity subsampling based direct down-conversion architecture suitable for software defined radio (SDR) receivers. The proposed topology only needs a single branch to down-convert and extract the in-phase (I) and quadrature (Q) baseband signals. Using a single branch down-conversion eliminates the I/Q mismatch issue of the traditional direct down-conversion receivers. Furthermore, the proposed receiver requires only simple circuit components compared to the well-known subsampling low-IF receiver architectures, especially in designing the RF band-pass filter. The simplicity of the proposed receiver architecture makes it appropriate for low-cost low-power applications. Moreover, the potential use over a wide range of frequencies makes the proposed receiver a suitable solution for multi-standard and multi-band applications.