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US 6,647,780 B1Granted
Slow wave structure sensor with zero-based frequency output
AssigneeMTS Systems Corporation
InventorDavid S. Nyce
Life of this patent
Estimating the term…
Abstract
An oscillating circuit is disclosed which is responsive to frequency variations caused by parameter changes in an associated slow wave structure sensitive element. A local oscillator and mixer circuit is used to subtract an offset frequency output to reset the oscillation frequency of the slow wave structure so that the output frequency will be in a range starting substantially at zero.
Claims17
A sensor unit for measuring changes in a parameter being sensed, comprising:
- a slow wave structure including (1) a slow wave structure sensitive element positioned and structured to be responsive to changes in the parameter and (2) a slow wave structure oscillating circuit having said slow wave structure sensitive element as a component, the changes of the parameter resulting in variations in said slow wave sensitive element affecting the operating frequency of said slow wave structure oscillating circuit;
- said output frequency of said slow wave structure, being said operating frequency of said slow wave structure oscillating circuit;
- a mixer circuit, said output frequency of said slow wave structure being an input into said mixer circuit;
- a local oscillator, said local oscillator generating at least one output frequency, said output frequency of said local oscillator circuit being a second input to said mixer circuit;
- said mixer circuit producing a difference signal equal to at least the difference between said output frequency of said slow wave structure minus said output frequency of said local oscillator circuit.
2 more elements
A method for measuring changes in a parameter, comprising the steps of:
- a. measuring the changes in parameter with a slow wave structure sensitive element;
- b. causing the change in the parameter to be expressed as an oscillation frequency in an oscillating circuit;
- c. generating a fixed frequency;
- d. mixing said oscillation frequency with said fixed frequency in a mixing circuit, said mixing producing a different signal equal to at least the difference between said oscillation frequency resulting from the change in the parameter minus said fixed frequency.
1 more element
Dependencies are inferred from the claim text.