Position sensor with unbalanced cyclic ratio

A sensor comprising:

• at least one rotary magnetic coder comprising a first circular magnetic track formed by a series of generator elements of a variable magnetic field, distributed so as to form N1 element pairs with a specified period T1, and a second circular magnetic track formed by a series of generator elements of a variable magnetic field, distributed so as to form N2 element pairs with a specified period T2, at least one of the magnetic tracks having at least one singular pole PS with at least one pair of singular generator elements with a spacing pitch different from the spacing pitch of the other generator elements of the track,
• at least two detection cells, each of said cells placed in relation to one said magnetic track and each delivering an electrical signal corresponding to changes in intensity of magnetic field, the detection cells or the magnetic tracks being offset from each other to allow the production of two de-phased digital signals, and
• logical resources for processing of digital signals delivered by the cells, said logical resources delivering a digital output signal with, a regular coding part S1 having an alternating succession of high levels and low levels corresponding to a specified cyclic ratio R1 and an irregular coding part S2 with at least one high level and one low level corresponding to a specified cyclic ratio R2,
• wherein at least the detection cell located in relation to the magnetic track with a singular pole PS is a single-element detection cell, and
• the generator elements of the magnetic tracks and the detection cells are arranged in dependence on the logical processing resources, such that the digital output signal has a constant period, both on the regular coding part S1 and on the irregular coding part S2 , the regular coding part S1 and the irregular coding part S2 having cyclic ratios R1, and R2 that are unbalanced and different from each other.