Methods and apparatus for an encoder
AssigneeSemiconductor Components Industries, LLC
InventorsSreenivasa Murthy Nerayanuru, Jeffrey Dennis Allgood
Life of this patent
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Abstract
Various embodiments of the present technology comprise a method and apparatus for an encoder. In various embodiments, the encoder is configured to remove impairments from the signals produced by a servo motor and compute a phase that is used to determine the rotary position of the servo motor. In various embodiments, the encoder is configured to remove a DC offset, improve amplitude mismatch, and compute a phase offset.
Claims19
An integrated circuit capable of receiving a first input signal and a second input signal, comprising:
- a first filter configured to compute a first quadrature of the first input signal;
- a second filter configured to compute a second quadrature of the second input signal;
- a first phase estimation circuit coupled to an output terminal of the first filter and configured to estimate a first phase according to the first input signal and the first quadrature;
- a second phase estimation circuit coupled to an output terminal of the second filter and configured to estimate a second phase according to the second input signal and the second quadrature;
- and
- a phase offset circuit coupled to the output terminals of the first and second phase estimation circuits and configured to compute a phase offset based on the first and second phases.
A method for computing a motor position, comprising:
- decimating a first input signal and a second input signal;
- computing a first quadrature of the first signal;
- computing a second quadrature of the second input signal;
- computing a first phase according to the first quadrature;
- computing a second phase according to the second quadrature;
- computing a phase offset based on the computed first and second phases;
- and computing the motor position based on the phase offset, the first phase, and a frequency.
A system capable of generating a first signal and a second signal, comprising:
- a motor assembly comprising:
- a motor having a motor position;
- and
- an optical encoder coupled to the motor and comprising:
- a first correction circuit configured to:
- apply a first gain to the first and second signals;
- apply a first DC offset correction to the first and second signals;
- generate first channel data;
- and
- generate second channel data;
- a second correction circuit coupled to an output terminal of the first correction circuit and configured to:
- apply a second gain to the first and second channel data;
- apply a second DC offset correction to the first and second channel data;
- generate corrected first channel data;
- and
- generate corrected second channel data;
- a signal processing circuit coupled to the second correction circuit and configured to:
- compute a first quadrature of the corrected first channel data;
- compute a second quadrature of the corrected second channel data;
- estimate a first phase according to the first signal corrected first channel data and the first quadrature;
- estimate a second phase according to the corrected second channel data and the second quadrature;
- and
- compute a phase offset based on the first and second phases.
Dependencies are inferred from the claim text.