Encoder signal analysis system for high-resolution position measurement
AssigneeCalifornia Institute of Technology
InventorsGang He, Harry A. Atwater
Life of this patent
Estimating the term…
Abstract
A signal analysis system for processing quadrature analog waveforms from an encoder. High-resolution position measurements for external measurement devices are obtained. A hardware component receives the quadrature analog signals from the encoder and processes these signals to generate low and high-resolution waveforms. These waveforms are then further processed and sent as first and second data streams to a computational component of the signal analysis system. The absolute phase angle (.THETA.) of the encoder's analog signal is determined by processing the data streams with the computational component. .THETA. is compared to a series of calibration factors to determine the position of the translating component of the external measurement device.
Claims17
A signal analysis system for processing output signals from an encoder comprising:
- a lower-resolution stage including a waveform processing element producing a processed signal, and a counter which counts an aspect of the processed signal to generate an integer value indicating information therefrom, a low-resolution analog-to-digital converter operating to digitize first portions of the output signals to form digital waveforms;
- a higher-resolution stage, coupled to said lower-resolution stage, and including a high-resolution analog-to-digital converter for digitizing second portions of the output signals to form a pair of digital sinusoidal waveforms;
- and,
- a computational component, responsive to the pair of digital sinusoidal waveforms from said higher-resolution stage and the integer value from said counter for calculating a position of the encoder,
- the computational component including a processor comprising:
- first calculating means for calculating a first phase value from the integer value;
- second calculating means for calculating a second phase value from a portion of one of the digital sinusoidal waveforms;
- and,
- adding means for adding the first and second phase values to determine a total phase value.
A method for processing a pair of analog signals from an encoder to determine a position of the encoder, comprising:
- receiving the analog signals;
- separating the analog signals into first and second portions;
- digitizing the first and second portions of the analog signals with the hardware component to form, respectively, digital square and sinusoidal waveforms representative of the analog signals;
- processing the digital square and sinusoidal waveforms with a computational component to determine a total phase value of the analog signal;
- and,
- calculating the position of the encoder from the total phase value.
Dependencies are inferred from the claim text.