Patent ID: 6504458
Filing Date: 2003-01-07
Classification: H03H

Abstract:
A tuning circuit having a resonance circuit comprising an inductor and a capacitor, and having a negative resistance circuit connected to the resonance circuit in series, comprising:a setting apparatus for calculating a serial resistance value rs of said resonance circuit and setting up a negative resistance value rn of said negative resistance circuit using said serial resistance value rs and a resistance value rd for obtaining a necessary Q value at an optimum resistance value RN, wherein said setting apparatus includes: a controller to provide effective serial resistance values equal to rs+rn for said tuning circuit to be in a weak oscillation state by controlling the negative resistance value rn, a detector device for detecting oscillation amplitude values e1, e2 at changing said effective serial resistance values r1, r2, and, a calculator device for calculating said serial resistance value rs by using said negative resistance values and said oscillation amplitude values and subtracting said serial resistance value rs from a resistance value Rd to obtain the necessary Q value.