Analysis of the small signal behaviour of MOS-transistors using the Fast Fourier Transform

The switching behavior of a p-MOS-transistor is analyzed with a computer program using the Fast Fourier Transform (FFT) as subroutine. With the known output signal of a linear system, the small behavior of a MOSFET in this case, the locus of the complex samples in the frequency domain can be computed. In this way a simple small signal equivalent circuit of a MOSFET could be derived using an inductance to simulate the delay caused by the channel formation, and which supplies the same results as a physical model described earlier.