Patent ID: 7688153

Claim:
An oscillating circuit arrangement comprising: a resonating arrangement with a first resonance frequency ω 0 further comprising a voltage controlled oscillator arrangement having at least one switch transistor being a tunable filter arrangement connected to the voltage controlled oscillator arrangement, wherein the filter arrangement is adapted to resonate at a second resonance frequency ω f , the second resonance frequency being a multiple n, n=1 or 2 of said first resonance frequency ω 0 , and being equal to the number of functional switch transistors of the VCO arrangement that is/are required for the VCO arrangement to oscillate at said first resonance frequency, said filter arrangement being adapted to be tunable such that a phase noise of the oscillating circuit arrangement can be minimized through tuning of the filter arrangement; and a control circuit adapted to establish the optimizing tuning voltage or current to be applied to the filter arrangement, wherein the control circuit is adapted to maximize an amplitude of the second resonance frequency ω f , the control circuit comprising an amplitude detector for sensing the amplitude of the signal resonating at the second resonance frequency ω f and second amplitude variation detection and control circuit for detecting whether the amplitude varies.