Nonlinear circuits are considered to be either memoryless or with memory. In memoryless circuits, the output of the circuit at time t depends only on the instantaneous input values at time t and not on any of the past values of its input. The output of such a circuit can be expressed in the form of a power series:

The output of a nonlinear circuit with memory at time t, on the other hand, depends on the input signal at time t as well as inputs that occurred in previous instances before t. The largest time delay on which the output depends determines the memory of the circuit. In the event where the output signal has infinite memory, that is a system with infinite nonlinear impulse response, the output signal may be best represented using integrals and differentials of the input signal. Generally speaking, a nonlinear circuit with memory with reactive elements can be modeled using a Volterra series, which is a power series with memory. In this chapter, the system requirements addressed can be sufficiently modeled with memoryless polynomials.

This chapter is divided into nine sections. In Section 5.1, the 1-dB compression point in the context of memoryless circuits is introduced. Section 5.2 discusses signal degradation due to desensitization and blocking, whereas Section 5.3 introduces intermodulation distortion and analysis. Cross modulation distortion is presented in 5.5 and harmonics generated by nonlinear circuits are discussed in Section 5.6. Section 5.7 discusses the phase noise implication...