Resonator systems with controlled quality factors including a resonator having a plurality of ports and a first quality factor greater than the system quality factor, and an amplifier providing negative feedback among the ports to render the system quality factor independent of the resonator quality...http://www.google.fr/patents/US5491604?utm_source=gb-gplus-shareBrevet US5491604 - Q-controlled microresonators and tunable electronic filters using such resonators
Q-controlled microresonators and tunable electronic filters using such ...
