Hi guys,
  Recently I have a doubt about one expression in one document in Analysis Column, named by "Simulating Switched-Capacitor Filters with SpectreRF". There is some difficultly in understanding it.
  On Page 6, there is a formula without any derivation (Expr. 6). Conventionally when we analysis the noise we treat it as continuous time random signal. But here Dr. Kun took it as discrete-time case. As far as I know, that the definition of PSD in continuous time domain is quite different from that in discrete time domain.  So how to bridge the gap between DTFT and continuous-time FT? Thank you all guys.


B.R
Q.L