Patent ID: 8775118

Claim:
An angle detection apparatus to perform angle detection of a rotary shaft of a rotating device to generate a first signal and a second signal orthogonal to the first signal by amplitude-modulating an excitation signal in accordance with a rotation angle using a resolver, comprising: a first A-D converter unit to receive the first signal, the first A-D converter unit to perform analog-to-digital conversion of the first signal; a second A-D converter unit to receive the second signal, the second A-D converter unit to perform analog-to-digital conversion of the second signal; a first delay circuit to receive a third signal outputted by the first A-D converter unit, the first delay circuit to perform a phase adjustment of the third signal; a second delay circuit to receive a fourth signal outputted by the second A-D converter unit, the second delay circuit to perform a phase adjustment of the fourth signal; and a phase detection adjustment unit to monitor phases of signals outputted by the first and second delay circuits, the phase detection adjustment unit to give phase adjustment commands to the first and second delay circuits, when a phase shift occurs.