High-Pass Filter

Low-Pass, High-Pass, Band-Pass, Band-Stop Filters

Digital filters are used for two general purposes:

• separation of signals that have been combined, and
• restoration of signals that have been distorted in some way.

A LPF (Low-pass filter) only allows low frequencies to pass through.

A HPF (High-Pass Filter) passes signals with a frequency higher than a certain cutoff frequency and attenuates signals with frequencies lower than the cutoff frequency.

A band-pass filter is a combination of a HPF and an LPF. It allows only a selected range of frequencies to pass through.

A band stop filter blocks a selected range of frequencies.

The Chebyshev Responses and Chebyshev Filters

Attenuation: a general term that refers to any reduction in the strength of a signal. Sometimes called loss, attenuation is a natural consequence of signal transmission over long distances. Roll-off: a rate at which attenuation increases beyond the cutoff frequency. The steepness of the transition between the pass-band and stop-band. Ripple: the maximum amplitude error of the filter in the passband in dB.

The Chebyshev response is a mathematical strategy for achieving a faster roll-off by allowing ripple in the frequency response. Analog and digital filters that use this approach are called Chebyshev filters.

Butterworth Filters

The Butterworth filter is a type of signal processing filter designed to have a frequency response that is as flat as possible in the passband.

An ideal electrical filter should not only completely reject the unwanted frequencies but should also have uniform sensitivity for the wanted frequencies

Ref

https://en.wikipedia.org/wiki/High-pass_filter https://www.analog.com/media/en/technical-documentation/dsp-book/dsp_book_Ch20.pdf https://www.dspguide.com/ https://www.rfpage.com/low-pass-high-pass-and-band-pass-filters-simple-explanation/ https://www.electronicsforu.com/technology-trends/learn-electronics/band-stop-high-low-pass-filter https://training.dewesoft.com/online/course/filters https://www.techtarget.com/searchnetworking/definition/attenuation https://ocw.mit.edu/courses/res-6-007-signals-and-systems-spring-2011/6ffe3f6c387555a8db26f1f3bbaddfb5_MITRES_6_007S11_lec24.pdf https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.butter.html https://en.wikipedia.org/wiki/Butterworth_filter