An oxygen sensor includes a base body portion; and a plurality of function layers laminated on a surface of the base body portion. The first connector includes a first main body defining an interior space, an insulative member received in the interior space, a center conductor retained within the insulative member, a flexible bushing and a magnetic member retained in the interior space. This delay difference is measured by a phase arbiter in each stage, which outputs an indication signal indicating whether the first event of two events in the first part precedes or succeeds a second event of the two events in the second part. There exists no rigid coupling between the disc and the hub, meaning that radial vibrations of the hub result in compression or decompression of the flexible joint, rather than in translation of the disc.