The oscillator comprises at least a first series of a multiple of four sub-assemblies each of which comprises an excitation terminal and an output terminal. The sub-assemblies are arranged in series in a closed loop. The output terminal of each sub-assembly is connected to the excitation terminal of the following sub-assembly. The output terminal of one of the sub-assemblies constitutes the output terminal of the oscillator. Each sub-assembly comprises excitation means and a nanowire which constitutes the electromechanical resonator and the piezoresistive detection means of movement of the resonator. A first terminal of the nanowire is connected to a first supply voltage. The second terminal of the nanowire constitutes the output terminal of the sub-assembly which is grounded via a corresponding resistive circuit. An input terminal of the excitation means constitutes the excitation terminal of the sub-assembly.