We discuss noise analysis techniques for large-size RF integrated circuits, possibly driven by multi-tone excitations. The steady-state solution of the system can be quasi-periodic and the size of the system can be huge. Advantages of the mixed frequency/time (MFT) method for quasi-periodic noise analysis is discussed. To do the noise analysis efficiently for large circuits, advanced numerical techniques such as sparse matrix, iterative solver, and preconditioning techniques are applied in our circuit simulator.