Reducing harmonic distortion by dithering
AssigneeUltraleap Limited
InventorsBenjamin John Oliver Long, Brian Kappus
Life of this patent
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Abstract
A digital signal generation assumes that a base frequency (the frequency with which the primitive phase angles are specified relative to) is equal to the carrier frequency for all relevant times. But this causes errors in the digital signals output to each array element transducer. Thus, it is necessary for the development of a signal generation system that is capable of producing a digital signal using the free selection of amplitude and phase. This is used to produce a substantially error-free signal that preserves the amplitude and phase relative to a constant base frequency while allowing the carrier frequency to vary.
Claims11
A system comprising:
- an electrical signal wherein the electrical signal has a plurality of pulse edges and is driven by an amplitude pulse width modulation and by a phase pulse width modulation;
- wherein at least one of the plurality of pulse edges is perturbed by dither on a phase angle drawn from a statistical distribution;
- wherein the statistical distribution is dependent on an instantaneous frequency at each of the plurality of pulse edges.
Dependencies are inferred from the claim text.