3rd Order Complex Delta-Sigma Modulator with Arbitrary Poles and Zeros Placement

A third-order complex delta-sigma modulation (CDSM) structure with cross-coupling paths is proposed and analysed. Although the conventional CDSM can reduce circuits complexity in digital transmitter systems, it suffers from other shortcomings like increasing algorithm complexity. This structure imports cross-coupling paths both at output and interstage, which realises decorrelation between zeros and poles. The advantage is that complex zeros can be arbitrarily placed, and thus, the reconfigurable digital wireless transmitter application can be satisfied; and the poles are not affected by zeros placement, which improves the flatness of signal transfer function.