Aliasing

Accurate signal sampling and reconstruction are crucial in various signal-processing applications. A time-domain signal's spectrum can be revealed using its Fourier transform. When this signal is sampled at a specific frequency, it results in multiple scaled replicas of the original spectrum in the frequency domain. The spacing of these replicas...

Consider a time-domain signal and its Fourier transform to reveal the spectrum.

Sampling the signal at a specific frequency creates multiple scaled replicas of the original spectrum.

If the sampling frequency is below the Nyquist rate, these replicas overlap, preventing the recovery of the original signal using a low-pass filter.