Oscillating circuit arrangement (10; 40; 50; 60) comprising: a resonating arrangement with a first resonance frequency ω o comprising a voltage controlled oscillator, "VCO", arrangement comprising a plurality of switch transistors (1 1, 1 2; 1 61, 1 62, 1 63, 1 64; 1 71, 1 72; 1 73, 1 74; 1 1 ', 1 2 '), wherein the VCO arrangement comprises a cross-coupled differential pair VCO with two functional switch transistors, wherein a source node or an emitter node of the cross-coupled differential pair VCO is common to said two functional switch transistors; characterized in that the oscillating circuit arrangement further comprises: a tunable filter arrangement (25; 25 5; 25 6; 25 7) connected to said common source node or said common emitter node; and control means adapted to establish an optimizing tuning voltage or current to be applied to the filter arrangement, the control means being connected to the tunable filter arrangement, and to said common source node or to said common emitter node; wherein said filter arrangement (25; 25 5; 25 6; 25 7) is adapted to resonate at a second resonance frequency ω f, the second resonance frequency being a multiple n, n= 2 of said first resonance frequency ω o, n being equal to the number of functional switch transistors of the VCO arrangement that are required for the VCO arrangement to oscillate at said first resonance frequency, said filter arrangement (25; 25 5; 25 6; 25 7) being adapted to be tuned such that a phase noise of the oscillating circuit arrangement can be minimized through tuning of the filter arrangement (25; 25 5; 25 6; 25 7); and wherein the control means comprises: an amplitude detector adapted to sense an amplitude of a signal resonating at the second resonance frequency ω f at the common source node or the common emitter node; second amplitude variation detection and control means adapted to detect whether said amplitude varies; and a control circuit adapted to maximize the amplitude of said second resonance frequency ω f signal based on the result of detection such as to minimize the phase noise of the oscillating circuit arrangement. a resonating arrangement with a first resonance frequency ω o comprising a voltage controlled oscillator, "VCO", arrangement comprising a plurality of switch transistors (1 1, 1 2; 1 61, 1 62, 1 63, 1 64; 1 71, 1 72; 1 73, 1 74; 1 1 ', 1 2 '), wherein the VCO arrangement comprises a cross-coupled differential pair VCO with two functional switch transistors, wherein a source node or an emitter node of the cross-coupled differential pair VCO is common to said two functional switch transistors; characterized in that the oscillating circuit arrangement further comprises: a tunable filter arrangement (25; 25 5; 25 6; 25 7) connected to said common source node or said common emitter node; and control means adapted to establish an optimizing tuning voltage or current to be applied to the filter arrangement, the control means being connected to the tunable filter arrangement, and to said common source node or to said common emitter node; a tunable filter arrangement (25; 25 5; 25 6; 25 7) connected to said common source node or said common emitter node; and control means adapted to establish an optimizing tuning voltage or current to be applied to the filter arrangement, the control means being connected to the tunable filter arrangement, and to said common source node or to said common emitter node; wherein said filter arrangement (25; 25 5; 25 6; 25 7) is adapted to resonate at a second resonance frequency ω f, the second resonance frequency being a multiple n, n= 2 of said first resonance frequency ω o, n being equal to the number of functional switch transistors of the VCO arrangement that are required for the VCO arrangement to oscillate at said first resonance frequency, said filter arrangement (25; 25 5; 25 6; 25 7) being adapted to be tuned such that a phase noise of the oscillating circuit arrangement can be minimized through tuning of the filter arrangement (25; 25 5; 25 6; 25 7); and wherein the control means comprises: an amplitude detector adapted to sense an amplitude of a signal resonating at the second resonance frequency ω f at the common source node or the common emitter node; second amplitude variation detection and control means adapted to detect whether said amplitude varies; and a control circuit adapted to maximize the amplitude of said second resonance frequency ω f signal based on the result of detection such as to minimize the phase noise of the oscillating circuit arrangement. an amplitude detector adapted to sense an amplitude of a signal resonating at the second resonance frequency ω f at the common source node or the common emitter node; second amplitude variation detection and control means adapted to detect whether said amplitude varies; and a control circuit adapted to maximize the amplitude of said second resonance frequency ω f signal based on the result of detection such as to minimize the phase noise of the oscillating circuit arrangement.