Band Stop Filter(BSF)

Band Stop Filter is complement of BPF where signal components at frequencies form ω1 to ω2 are stopped and all others are passed. These filters are sometimes known as “Notch filters”. Notch filters are used to remove resonances.

fig: band stop filter

A band stop filter also known as notch filter is used in circuits that block only a select range of frequencies and allows others to pass through.

fig: Gain and Attenuation Relation

\[
|H(\omega)| = 
\begin{cases} 
0 & \text{for } B_1 < \omega < B_2 \\[6pt]
1 & \text{otherwise}
\end{cases}
\]

Where, Stopband: 𝐵1<𝜔<𝐵2 and Passband:𝜔<𝐵1 ​and 𝜔>𝐵2