An oscillator has an oscillator output emitting an oscillating signal. The oscillator includes oscillator cores which each have a same circuit topology. A set of configuration switches couple a selected number of oscillator cores in parallel to generate the oscillating signal. The oscillator cores are arranged with a symmetry around a central axis. The planar inductors of the oscillator cores are arranged in a petal-like pattern with the planar inductors forming the petals of the petal-like pattern. The selected coupling of the oscillator cores in made in response to a selected phase noise threshold of a modulation device which receives the oscillating signal.