Rotation angle detector, rotation angle detection method, and image forming apparatus

A method of detecting a rotation angle, the method comprising:

• detecting a rotation angle of a rotating body according to a plurality of detection signals that vary depending on the rotation angle of the rotating body and have phases different from each other, to output the detected rotation angle as a detection angle;
• generating pseudo harmonics based on a multiplied detection angle obtained by multiplying the detection signal by a specified number;
• removing the pseudo harmonics from the detection signals, to output corrected detection signals from which the pseudo harmonics are removed to the detecting of the rotation angle, the detection angle being generated based on the corrected detection signals;
• and
• generating amplitude of the pseudo harmonics by
• detecting an amplitude value of desired one of the detection signals at a desired timing;
• and
• determining a harmonics amplitude value of the harmonics included in the detection signal, according to the amplitude value of the detection signal, wherein
• the pseudo harmonics of an amplitude value that corresponds to the harmonics amplitude value are generated.

A rotation angle detector for detecting a rotation angle of a rotating body, the rotation angle detector comprising:

• circuitry configured to
• output a plurality of detection signals that vary depending on the rotation angle of the rotating body, the detection signals having phases different from each other;
• detect the rotation angle of the rotating body according to the detection signals, and output the detected rotation angle as a detection angle;
• generate pseudo harmonics based on a multiplied detection angle obtained by multiplying the detection angle by a specified number;
• remove, from each one of the detection signals, the pseudo harmonics generated by the pseudo harmonics generator, to output corrected detection signals from which the pseudo harmonics are removed, the detection angle being generated based on the corrected detection signals;
• and
• generate amplitude of the pseudo harmonics by
• detecting an amplitude value of desired one of the detection signals at a desired timing;
• and
• determining a harmonics amplitude value of the harmonics included in the detection signal, according to the amplitude value of the detection signal wherein
• the circuitry is configured to generate the pseudo harmonics of an amplitude value that corresponds to the harmonics amplitude value.