Tag Archives: Filter

High-Q Notch Filter with Active Twin T Network

Posted on March 13, 2011 by Rend

This is a circuit of High-Q Notch Filter. This circuit consist of LM102 and a twin “T” network. Twin T network sum two signal from different path with different phase shift. At certain frequency, the phase shift will be 180 … Continue reading →

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Bandpass Filter for Bell103A Originator Modem

Posted on March 3, 2011 by Rend

Bell103A modem standard specify that the originator (the caller) uses 1070Hz and 1270Hz frequency shift keying for transmission, and listen for 2025/2225Hz FSK transmitted by the answering modem. This bandpass circuit filter out any frequency beyond 2025-2250 Hz to improve … Continue reading →

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Two Op-Amps 60 Hz Notch Filter

Posted on January 25, 2011 by Rust

Notch filter is a filter that remove a certain B. Ideally a notch filter will remove only single point of frequency  component, but practically it will remove a limited range of frequency spectrum. The spectrum should have very small bandwidth … Continue reading →

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