Howtosignalprocessing
- What happens when a signal is sampled at less than the Nyquist rate?
- Why ideal low-pass filter is not possible?
- Why is a low-pass filter not physically realizable?
- What is the disadvantage of ideal low-pass filter?
What happens when a signal is sampled at less than the Nyquist rate?
When the sampling frequency drops below the Nyquist rate, the frequencies will crossover and cause aliasing.
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.
Why is a low-pass filter not physically realizable?
The Paley and Wiener criterion implies that ideal filters are not physically realizable because in a certain frequency range for each type of ideal filters. Therefore, approximations of ideal filters are desired.
What is the 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.
