manodipan wrote on Jun 24th, 2008, 12:51am:Definitely this is not a continuous time filter,but a switched capacitor filter.Moreover it is not opamp based,rather comparator based,
and it has transients before settling to final value.Also it does not have any steady state
As far as clock and input signal are periodic and circuit is stable(this means circuit is never oscillative), circuit always results in steady state.
Settling transient is repeated periodically in steady state.
If you want to consider input signal amplitude, apply two large signal drives(one is clock, the other is signal).
There are four possibilities in simulation.
(1) PSS(two large tones, signal frequency is swept as large.
(2) PSS(two large tones/PAC, signal frequency is fixed as large but you can observe signal frequency characteristics as small.
(3) QPSS(two large tones), signal frequency is swept as large.
(4) QPSS(two large tones/QPAC, signal frequency is fixed as large but you can observe signal frequency characteristics as small.
If you want to insist on DFT from transient analysis, explain situation assuming actual instruments.
What instruments do you use ?
Have you measured actual DUT using actual instruments ?
Do you assume real time spectrum analyzer or FFT analyzer where short time interval overlapped FFT is invoked ?