Band-limited filter

1. What is band limiting filter?
2. What is meant by band-limited?
3. What is band-limited channels?
4. Why are band limiting filters used before sampling?
5. Why is band limiting necessary?

What is band limiting filter?

Bandlimiting is the limiting of a signal's frequency domain representation or spectral density to zero above a certain finite frequency.

What is meant by band-limited?

A signal is said to be band-limited if the amplitude of its spectrum goes to zero for all frequencies beyond some threshold called the cutoff frequency.

What is band-limited channels?

band-limited channel A transmission channel with defined finite bandwidth. All physically realizable channels are band-limited by the constraints of the transmission medium and the drivers and receivers. The bandwidth may be deliberately constrained by filtering to limit the emission of or susceptibility to EMI.

Why are band limiting filters used before sampling?

To avoid contamination of the signal by the aliased frequencies, you would first band-limit (lowpass filter) the continuous-time signal and only then sample it.

Why is band limiting necessary?

For data communications, a signal, which is to be transmitted, has an infinite number of terms in its Fourier transform. However, when this signal needs to be transmitted through a channel of fixed bandwidth, band-limiting is required.