Simulation of a dissipative LC filter using a reduced number of active elements

✍ Scribed by Yukio Ishibashi; Kazuhisa Tsudzuki; Kazuhiro Shouno

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 195 KB
• Volume: 81
• Category: Article
• ISSN: 1042-0967
• DOI: 10.1002/(sici)1520-6440(199806)81:6<9::aid-ecjc2>3.0.co;2-h

✦ Synopsis

This paper describes a method to realize an LC simulation-type active RC filter, using a small number of operational amplifiers. The proposed filter is realized by simulating a doubly resistor-terminated ladder LC filter, composed of inductors with negative loss and capacitors with positive loss. The number of operational amplifiers used in the filter can be reduced to approximately twothirds, compared to the conventional leapfrog construction. Another feature is that the capacitors have the same value. A method is shown first in which a reactance element with loss is realized by using a small number of operational amplifiers. Then, a fifth-order Chebyshev low-pass filter is constructed, and it is shown that the measured values agree well with the theoretical values. Finally, the element sensitivity is analyzed by computer, and it is shown that the proposed filter has almost the same element sensitivities as the conventional leapfrog filter.