Which of the following is NOT a commonly used pulse-shaping filter in communication systems?

Concept:

In digital communication systems, pulse-shaping filters are used to control bandwidth and reduce intersymbol interference (ISI). Commonly used pulse-shaping filters include Raised Cosine, Gaussian, and Sinc filters. These are specifically designed to shape pulses for transmission.

High-pass filters, on the other hand, are general-purpose frequency filters used to block low frequencies, and they are not typically used for pulse shaping in baseband communication.

Evaluation of Options:

Option 1: Raised cosine filter –  Incorrect
Widely used in pulse shaping due to excellent ISI performance.

Option 2: Sinc filter –  Incorrect
Ideal pulse-shaping filter (though impractical due to infinite length).

Option 3: Gaussian filter –  Incorrect
Used in GMSK and other modulation schemes.

Option 4: High-pass filter –  Correct
Not used for pulse shaping; used for removing low-frequency components.