--- In LTspice@..., Andy <Andrew.Ingraham@...> wrote:
Now coming to the issue in thread, I have this feeling that frequency is
just a frequency for an opamp, Whether it is that of input source or that
of any component variation.
I am not sure what you mean. But an op-amp is no different than other
components. Frequency applies to every thing in the circuit, not just
op-amps.
What I mean here is, in the circuit whether it is 10KHz variation of R2 or that of vin, your opamp always 'thinks' the same- it is working at 10KHz.
This motivates me to put this hypothesis that i can plot the Bode due to
rapid variation of R2 by just assuming R2 to be constant at its maximum
value and sweeping the frequency of input vi (Vi should be changed to
AC source).
That's an interesting hypothesis, but I think it's not true. I think
that varying R2 (while a DC signal is placed at the input to the
op-amp) is very different than simply applying a varying signal to the
amp's input. I suspect that if you try it (with .TRAN analysis) you
would see different results.
Could you kindly show it by a simulation that hypothesis is wrong?
One thing I also just noticed about your earlier circuit, was that you
were varying R2 between 3000 and -1000 ohms. Did you really intend
for R2 to go negative?
Thanks for pointing it out. That was unintentional and my carelessness. Due to this comment( and after changing amplitude of sinusoid) I got it today what Sedra means when he writes that limited bandwidth is linear phenomenon and doesn't cause distortion (while SR does).
Regards,
Andy
