A semiconductor apparatus includes a semiconductor substrate of a first conductivity type, a base region of a second conductivity type formed on a principal surface of the semiconductor substrate, a trench formed in a periphery of the base region, and an endless source region of the first conductivity type formed on a surface of the base region along the trench. VCS is used to generate high likelihood candidates for Multiple Input Multiple Output demodulation that approaches optimal maximum a posteriori performance with reasonable complexity. The computer determines aerodynamic drag acting on the rider on the vehicle from the received signal.