Inductive position sensor

A rotary position sensor comprising:

• a transmitter coil adapted to be energized by a high frequency current source,
• a first receiver coil adjacent said transmitter coil and concentrically arranged about an axis, said first receiver coil having an even number N of loops wherein adjacent loops of the first receiver coil are oppositely wound,
• a second receiver coil separate from the first receiver coil and adjacent said transmitter coil and concentrically arranged about said axis, said second receiver coil having number N loops wherein adjacent loops of the second receiver coil are oppositely wound, wherein said second receiver coil is angularly offset from said first receiver coil by 180/N degrees,
• a noncircular coupler constructed of an electrically conductive material rotatably mounted about said axis so that said coupler overlies at least a portion of said first and second receiver coils so that one of said receiver coils generates a sine function upon rotation of said coupler and the other of said receiver coils generates a cosine function upon rotation of said coupler,
• a circuit which processes output signals from both said first and second receiver coils and generates an output signal representative of the rotational position of said coupler,
• wherein said circuit computes the arctangent of the output signal from said first and second receiver coils.