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US 4,208,918 AGranted
Digital pressure sensor
AssigneeSharp Kabushiki Kaisha
InventorRyuichi Miyamae
Life of this patent
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Abstract
A first oscillator is associated with a pressure detector so that frequency of an output signal of the first oscillator varies in response to variations of the detected pressure. A second oscillator having a same construction as the first oscillator is provided for determining a sampling period of the output signal of the first oscillator, thereby compensating for variations of the frequency of the output signal derived from the first oscillator due to variations of temperature, humidity, a power supply voltage, etc.
Claims9
A digital pressure sensor comprising:
- a first oscillator means for developing a first output signal;
- frequency variation means for varying the frequency of said first output signal in response to variation of a detected pressure;
- second oscillator means for developing a second output signal;
- said first and second oscillator means being subjected to changes in temperature, humidity, and power supply voltage thereby causing the frequency of said first and second output signals to vary in response thereto;
- said second oscillator means having a similar construction relative to said first oscillator means, said similar construction of said second oscillator means relative to said first oscillator means cancelling the variations in frequency of said output signals from said first and second oscillator means due to variations in said temperature, humidity, and power supply voltage;
- and
- gate means responsive to said second output signal for determining a sampling period of said first output signal.
4 more elements
A digital pressure sensor comprising:
- a first oscillator for developing a first output signal;
- frequency variation means for varying the frequency of said first output signal in response to variation of a detected pressure;
- a second oscillator for developing a second output signal, said second oscillator means having a similar construction as said first oscillator;
- gate means responsive to said second output signal for determining a sampling period of said first output signal;
- and
- driver means for applying an output signal of said gate means to a display device for displaying the detected pressure.
3 more elements
Dependencies are inferred from the claim text.