7 Impact of Imperfections on the Performance of M-phase Filters
Although a high-Q M-phase filter has a simple structure, there are numerous implementation-related imperfections that must be scrutinized carefully and evaluated for their impact on the filter. The phase noise of the LO clocks, the second-order nonlinearity of the switches, the phase error between the LOs, and the harmonic downconversion and thermal noise of switches are examples of some of these imperfections. We will examine the impact of these imperfections in this chapter. For the sake of simplicity, we will discuss the effects of these imperfections in the four-phase bandpass filter but will apply our findings to the M-phase high-Q bandpass filters.