Offset, Flicker Noise, and Ways to Deal with Them

After almost one century of research into flicker noise, we still do not know as much about it as we would like to: we do not know enough about its origin, nor do we know everything about its behaviour, nor has the last word about good methods to fight it been spoken: effectively, we still are like Alice standing in front of the rabbit hole, before she enters the Wonderland . . . So the intent of this chapter is to give the reader an idea of what flicker noise is, how it is connected to other low-frequency noise effects, and what today’s designers do to fight it. This chapter will just give a broad overview, focusing on concepts and design philosophy, providing just as much mathematics as is strictly necessary. Interested readers will have to follow the literature references to find out details about mathematics and design. In this chapter, a section on the nature of flicker noise is followed by a section on switched-capacitor techniques and noise sampling. Three more sections deal with the three main techniques used against flicker noise, which are large-scale excitation, chopping, and correlated double sampling. An appendix contains information on how to simulate flicker noise in Matlab, and finally, a short annotaded literature list is given, inviting the reader to find out by herself or himself how deep the rabbit hole really is.