Question

A Low-pass filter circuit has a cut-off frequency of 1.23 kHz. The bandwidth of the filter is ______________

(a) 2.46 kHz

(b) 1.23 kHz

(c) 0.615 kHz

(d) 3.69 kHz

I had been asked this question by my college professor while I was bunking the class.

My doubt stems from Ideal LPF, HPF, BPF and BSF Characteristics topic in chapter Signal Transmission Through Linear Systems of Signals and Systems

Answer 1

Correct answer is (b) 1.23 kHz

The explanation is: The bandwidth is defined as the highest cut-off frequency to the lowest cut-off frequency. Here the lowest cut-off frequency is Zero.

For a Low-pass filter, Cut-off Frequency = Bandwidth of the filter

∴ Bandwidth = 1.23 kHz.