Why are the bandwidth and AC response different for Vpulse and Asia as inputs in a GmC filter?

[sudeep_]

Why bandwidth and ac response is different for Vpulse and Vsin as input in GmC filter

Hi,

I used both vpulse and vsin to verify the GmC low pass filter in Cadence spectre, but the f-3dB bandwidth and ac response appears with different values.
I set the ac magnitude for both signal is same like 1V. However, the bandwidth and ac response does not change for miller compensated opamp.

Can anyone suggesation in this.

 

[FvM]

Re: Why bandwidth and ac respones is different for Vpulse and Vsin as input in GmC fi

Sounds like a useless setup. Bandwidth respectively ac response is defined for sine input signals, not square wave.

Usually AC response is determined for small signal, e.g. using AC analysis of a circuit simulator (with VAC source). A large signal transient analysis can be performed with different waveforms (e.g. VSIN or VPULSE), but usual power bandwidth measurements are also using sine. If you feed a square wave to the filter, the output waveform isn't a square wave in the general case, how would you determine the gain then? Each spectral component of the square wave is amplified with different gain and phase.