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US 7,458,656 B2Granted
Measuring a pressure difference
AssigneeHewlett-Packard Development Company, L.P.
InventorDavid E. Smith
Life of this patent
Estimating the term…
Abstract
Embodiments of measuring a pressure difference are disclosed.
Claims12
A method comprising:
- measuring a pressure difference between a colorant in a container and a surrounding volume, wherein measuring generates a differential output signal from an input voltage, the differential output signal having a magnitude corresponding to the measured pressure difference and including an offset voltage;
- producing an amplified voltage from the differential voltage signal, the offset voltage being amplified in the amplified voltage;
- producing a first summed voltage output from the amplified voltage and a reference voltage;
- producing an approximation of the amplified offset voltage;
- producing a second summed voltage by reducing the first summed voltage by an approximation of the amplified offset voltage;
- producing a digital output voltage from the second summed voltage and the reference voltage, the digital output voltage;
- utilizing the digital output voltage to correlate the pressure difference with an amount of the colorant remaining in the container;
- and
- recording the amount.
6 more elements
A computer readable medium having instructions for causing a device to perform a method, comprising:
- measuring a pressure difference between a colorant in a container and a surrounding volume, wherein measuring generates a differential output signal from an input voltage, the differential output signal having a magnitude corresponding to the measured pressure difference and including an offset voltage;
- producing an amplified voltage from the differential voltage signal, the offset voltage being amplified in the amplified voltage;
- producing a first summed voltage output from the amplified voltage and a reference voltage;
- producing an approximation of the amplified offset voltage;
- producing a second summed voltage by reducing the first summed voltage by an approximation of the amplified offset voltage;
- producing a digital output voltage from the second summed voltage and the reference voltage, the digital output voltage;
- utilizing the digital output voltage to correlate the pressure difference with an amount of the colorant remaining in the container;
- and
- recording the amount.
6 more elements
Dependencies are inferred from the claim text.