Direct upconversion of transmission signal employing a notch filter

摘要

A direct upconversion system communication semiconductor integrated circuit (200) includes a frequency converter circuit (233) for up-converting a transmission signal and a notch filter 236 (NTF) located at a subsequent stage of the frequency converter circuit 233. The notch filter NTF 236 cuts off at least third-order harmonics of a local signal. A further filter may additionally cut off second and fifth-order harmonics.