High-pass filter

A high-pass filter is a system (often a circuit) with a frequency response that filters out low frequencies and passes through high frequencies (i.e., it has a high frequency passband and a low frequency stopband). The transfer function is generally given by:

$$T(s)=\frac{Ks}{s+\alpha }=\frac{\frac{Ks}{\alpha }}{1+\frac{s}{\alpha }}$$

where $K$ is the gain and $\alpha$ is a frequency. Its gain plot looks like this.¹ And its phase plot:

Circuits

A basic high-pass filter can be constructed with an RL circuit.

See also

• Low-pass filter
• Bandpass filter
• Bandstop filter

Footnotes

1. From Prof Najm’s notes, lecture 29. ↩