Time based digital-to-analog conversion of a precision variable amplitude sine wave

A time based digital converter for converting a digital word to a precise analog sinusoidal signal comprising:

• means for computing an amplitude of an analog sinusoidal signal;
• means for receiving the amplitude of the analog sinusoidal signal, and for receiving a clock signal from a connected clock, and for calculating a pulse width corresponding to the amplitude received from said means for computing an amplitude and the clock signal;
• means for generating a waveform instruction for controlling a gate array means based on the pulse width and the amplitude
• gate array means for generating a first waveform from first reference voltage source connected to said gate array means, and a second waveform from a second reference voltage source connected to said gate array means, where a period of said first and second waveforms are controlled by said pulse width;
• and
• means for combining said first and second waveforms into a periodic analog signal having a desired amplitude and period.

An inertial input processing circuit for a hemispherical resonator gyroscope comprising:

• rate control means for computing a fraction of a maximum opposing inertial rate that is required to null a standing wave precessing due to an inertial input;
• compute pulse width means for determining periods of a connected clock corresponding to the fraction of the maximum opposing inertial rate;
• net rate block means for determining a net rate from the periods of the connected clock;
• gate array means for generating wave forms corresponding to said periods of the connected clock using a switching logic;
• routing means for routing the signals corresponding to said waveforms to control electrodes on the hemispherical resonator gyroscope for nulling the standing wave.

A hemispherical resonator gyroscope having a time based digital-to-analog conversion of a precision variable, said digital-to-analog converter comprising:

• a rate determining software component for calculating the rate of a standing wave precess under the influence of an inertial input;
• a pulse width software component for converting the rate calculated by the rate determining software component into digital words corresponding to a repetitive signal needed to null the standing wave;
• a net rate software element for recomputing the rate estimate to account for truncation, based on the digital words converted from said pulse width software component;
• a gate array comprising digital counters for generating digital signals corresponding to the digital words and the number of periods of a clock attached to the gate array, where said gate array uses digital logic to switch between reference voltage sources to create a repetitive signal from waveforms of varying periods;
• and
• a connection between said gate array and control means on said hemispherical resonator gyroscope for nulling the standing wave based on the repetitive signal from said gate array.

A method for nulling an oscillation from a digital signal comprising the steps of:

• computing an amplitude digital word representing a fraction of a maximum sine wave voltage signal required to null the oscillation;
• determining first and second period digital words to be used as counters in a gate array;
• determining a net rate which is proportional to an amplitude of a first harmonic sine wave of a resultant repetitive signal;
• providing a gate array comprising dedicated digital counters for generating two digital signals;
• and
• generating a repetitive signal with a variable period selected from the values of the first and second period digital words.

A method for generating a variable sine wave to null a digital input comprising the steps of

• computing a fraction of a maximum amplitude sine wave to null the digital input;
• calculate first and second periods of the variable sine wave based on the fraction of the maximum amplitude sine wave;
• communicate the first and second periods of the variable sine wave to a gate array connected to two reference voltage signal generators;
• and
• combining the two reference voltage signals from the reference voltage signal generators according to the calculated first and second periods.

A digital to analog converter for generating a variable period sine wave comprising:

• a digital amplitude determiner for evaluating the digital amplitude of the variable period sine wave;
• a pulse width generator for calculating the variable periods of the sine wave based on a frequency of an input signal and said digital amplitude of the variable period sine wave;
• a gate array for controlling two reference voltage signals according to said variable periods of the sine wave, with each reference voltage signal assigned to one of said periods;
• and
• a switching circuit for combining the two reference voltage signals into a composite variable period sine wave.