Low pass filter output showing instability

1. Why ideal low-pass filter is not possible?
2. How do I know if my low-pass filter is working?
3. Is ideal LPF stable?
4. What is the biggest disadvantage of ideal low-pass filter?

Why ideal low-pass filter is not possible?

However, it is practically not possible to implement an ideal lowpass filter since the required impulse response is infinitely long.

How do I know if my low-pass filter is working?

When testing a low-pass filter, generally you have to use an arbitrary waveform generator (Arb) to create test tones to pass through the filter to measure the relative gain or attenuation of each tone to find the cutoff frequency of the filter.

Is ideal LPF stable?

As a consequence, the ideal lowpass is not BIBO stable. We can use a technique that we developed in the proof of the stability theorem. And so for instance if we take omega c equal to pi over 3 The impulse response of the ideal filter will be one-third sinc of n over 3.

What is the biggest disadvantage of ideal low-pass filter?

First Order Low Pass Filter

While this configuration provides good stability to the filter, its main disadvantage is that it has no voltage gain above one. However, although the voltage gain is unity the power gain is very high as its output impedance is much lower than its input impedance.