Methods and apparatus for generating a sinusoidal motor drive signal for a MEMS gyroscope
AssigneeHoneywell International Inc.
InventorStanley A. White
Life of this patent
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Abstract
An apparatus is described which reduces a time delay and a resultant phase shift in a gyroscope motor drive signal. The motor drive signal originates from a numerically controlled oscillator whose output is sampled at a predetermined rate. The apparatus includes a first element which upsamples the oscillator output signal samples and a band pass filter configured to receive an output from the first element and remove spectral components from the output of the first element. The apparatus further includes a third element which generates a tuning parameter, β′o, for tuning of the band pass filter and a scaling multiplier configured to normalize an output of the filter.
Claims26
An apparatus to reduce a time delay and a resultant phase shift in a gyroscope motor drive signal, the motor drive signal originating from a numerically controlled oscillator having an output, the oscillator output being sampled at a predetermined rate, said apparatus comprising:
- a first element which upsamples the oscillator output samples;
- a band pass filter configured to receive an output from said first element and remove spectral components of the output of said first element;
- a third element which generates a tuning parameter, β′o, to tune said band pass filter, and
- a scaling multiplier configured to normalize an output of said filter.
A method for reducing a time delay and a resultant phase shift in a gyroscope motor drive signal which originates from a numerically controlled oscillator, said method comprising:
- placing I−1 zero value samples between each pair of oscillator output samples, I being an integer;
- filtering spectral components from the combined oscillator output samples and zero value samples;
- generating a tuning parameter, β′o, for said filtering;
- and
- scaling an output of said filtering.
An angular rate measurement system comprising:
- a gyroscope configured to sense an angular rate input and provide a modulated angular rate information signal and a sinusoidal demodulation reference signal;
- a numerically controlled oscillator (NCO) configured to receive as an input a tuning parameter β, which is a digitized signal derived from the sinusoidal demodulation reference signal, said oscillator further configured to provide output samples;
- an automatic gain control (AGC) circuit configured to amplify the output samples of said NCO;
- an interpolator configured to place I−1 zero value samples between each pair of amplified output samples, said interpolator comprising a filter configured to filter extraneous spectral components from the combined amplified output samples and zero value samples, generate a tuning parameter, β′o, for said filter, and scale the filtered samples to be output from said interpolator, where I is an integer;
- and
- a digital-to-analog converter and filter, said converter and filter configured to produce a motor drive signal from an output of said interpolator.
Dependencies are inferred from the claim text.