Topic: Signals and Systems
For a practical low pass filter, the ideal amplitude and phase response will be
- A. Amplitude is a flat rectangular pulse, Group Delay is a flat horizontal line
- B. Amplitude is a flat rectangular pulse, Group Delay is a sloped line
- C. Amplitude has smooth roll-off, Group Delay is a flat horizontal line
- D. Amplitude has smooth roll-off, Group Delay is a sloped line
Answer: A. Amplitude is a flat rectangular pulse, Group Delay is a flat horizontal line
Explanation: For an ideal low pass filter, the amplitude response should be flat in the passband (a rectangular pulse shape) and zero outside. The phase response should be perfectly linear, which corresponds to a constant (flat) group delay in the passband. The official key marks option (a) which visually corresponds to flat amplitude and flat group delay.