Electronic control throttle valve apparatus, non-contact rotation angle detecting apparatus and signal processing apparatus for Hall element

In an electronic control type throttle valve apparatus, a throttle valve position sensor B includes a magnet 31 provided at a throttle valve shaft 40 and a hall element which output changes in accordance with the rotational deviation of the magnet 31. The hall element 60 is housed within a sensor chip 6 together with an amplifier circuit 62. In a control unit provided separately from the sensor chip 6, there are provided with an A/D conversion circuit for converting an analog output from the hall element 61 through the amplifier circuit into a digital signal and a digital processing circuit for performing temperature compensation and zero-span adjustment of the hall element 61 in a digital manner.