Analog to digital converters
AssigneeHamilton Sundstrand Corporation
InventorsMichael A. Wilson, Harold J. Reyes
Life of this patent
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Abstract
A sinusoidal-amplitude-to-digital-output circuit includes a comparator with an input terminal, a reference terminal and an output terminal. A digital bus is connected to the output terminal. A reference voltage source is connected to the reference terminal. A feedback resistor is connected in parallel with the comparator between the output terminal and the input terminal to provide hysteresis for noise rejection such that circuit converts voltage received at the input terminal into a digital pulse-width modulated waveform that varies non-linearly with amplitude of the voltage received at the input terminal.
Claims17
A circuit to allow an amplitude and frequency of a sinusoidal voltage waveform to be digitally monitored, comprising:
- an input configured to receive the sinusoidal voltage waveform;
- and
- an output in operable communication with the input configured to provide a duty cycle having a nonlinear relationship to the amplitude of the sinusoidal voltage waveform such that an amplitude and frequency of the sinusoidal voltage waveform can be calculated from just the duty cycle,
- wherein the circuit is a sinusoidal-amplitude-to-digital-output (SADO) circuit, wherein the input and output comprise:
- a comparator with an input terminal, a reference terminal, and an output terminal;
- a digital bus connected to the output terminal;
- a reference voltage source connected to the reference terminal;
- and
- a feedback resistor connected in parallel between the output terminal and the input terminal to convert an input voltage received at the input terminal into a digital pulse-width modulated (PWM) waveform that varies non-linearly with amplitude of the input voltage.
A method of monitoring amplitude and frequency of a sinusoidal voltage waveform comprising:
- receiving an input voltage with a sinusoidal waveform at a comparator input terminal;
- receiving a reference voltage at a comparator reference terminal;
- generating a digital pulse width modulation (PWM) signal whose duty cycle varies nonlinearly with an amplitude of the sinusoidal voltage waveform;
- analyzing the digital PWM signal;
- calculating, using the just the digital PWM signal, an amplitude and frequency representative of the sinusoidal voltage waveform;
- switching an output voltage applied at a comparator output terminal from a first voltage to a second voltage when amplitude of the input voltage crosses a low-to-high threshold;
- and
- switching the output voltage applied at the comparator output terminal from the second voltage to the first voltage when amplitude of the input voltage crosses a high-to-low threshold.
Dependencies are inferred from the claim text.