Selectable bandwidth notch filter

This circuit is a variable audio bandpass filter that features a low cutoff adjustable from approximately 25 Hz to 700 Hz and a high cutoff adjustable from 2.5 kHz to over 20 kHz. The roll-off is set at 12...

This is a second-order low-pass filter with a programmable cutoff frequency. The circuit should be driven from a low-source impedance, as there are paths from the output to the input through the unselected networks. Virtually any filter function that...

This project extends two previous projects: the first involves adding an active filter (APF) type high-Q bandpass feature to the second receiver of the FT-2000. The second aspect is inspired by childhood memories of active filters. An active audio...

The acoustic filters are met in various points in the sound systems. The knownest application they are the filters baxandal for regulating tone low and high frequencies and filters crossover where the acoustic region is separated in subareas, in...

The active filter is a state variable filter with bandpass, high-pass, and low-pass outputs. It is a classical analog computer method of implementing a filter using three amplifiers and only two capacitors. The state variable filter is a versatile circuit...

A subsonic filter is primarily utilized in low-frequency technology. It is commonly employed to eliminate very low frequencies that can cause distortions in music recording or reproduction. A subsonic filter is an electronic circuit designed to attenuate frequencies below a...