- TL;DR Summary
- Trying to make sense of the stability of a negative feedback.
What is the proper way of doing it then? Isn't the difference f(x)-g(x) supposed to be delayed by 90 deg when it passes the loop?Starting with the calculation for h1 you actually apply a phase lag of 180 degrees. The period of the signal is π so h(x-π/2) will lag h(x) by half a period.
If you want that, you should use a delay of a quarter of the full period, so you must use h1(x) = h(x-π/4). Your calculation of g(x) is still correct because sin (2x - π/2) = sin (2 (x-π/4)) so you have the correct delay there.What is the proper way of doing it then? Isn't the difference f(x)-g(x) supposed to be delayed by 90 deg when it passes the loop?
One problem with Spice simulations is that the frequency response may look good, but the circuit will be unstable in the time domain. It is easy to get it wrong if it becomes non-linear.This approach uses a circuit simulator such as the free LTSpice. The advantage of such a simulator is that it uses circuit components and automatically handles the appropriate equations based on the components used.
When the input signal is a unit phasor.Increase the amplifier gain, G, to 1,000,000
Summary:: Trying to make sense of the stability of a negative feedback