Apparatus and method for determining the position and motion of an object and for precise measurement of phase-related values
First Claim
1. Measurement apparatus comprising:
- means for providing first and second signals of constant frequency and phase;
means for producing a phase shift in said first signal proportional to a phenomenon, property, or condition to be measured;
means for combining said phase-shifted first signal with said second signal to extract a third signal at a difference-frequency between the first and second signals; and
phaselocked loop means for producing an output signal phaselocked to said third signal, wherein phase changes in said third signal produce phase changes in said phaselocked loop output signal that are substantially greater than corresponding phase changes in said third signal.
0 Assignments
0 Petitions
Accused Products
Abstract
In one embodiment, a high-resolution measurement apparatus and method determine the position and motion of an object such as a human hand relative to a sensor array. Capacitance transferred to the array by the object within a sensor field produces minute phase changes in a fixed-frequency reference signal applied to the several elements of the array. The phase changes are measured by first heterodyning the phase-shifted reference signal with a second reference signal to obtain a low frequency intermediate signal, and then employing a phaselocked loop to multiply the phase information in the intermediate signal by orders of magnitude, thereby permitting the use of conventional methods to measure the resulting greatly magnified phase changes. Other embodiments provide direct digital measurement of unknown electrical properties, such as capacitance, inductance, and resistance. In general, principles of the invention may be used to provide precise measurement of phenomena, properties, or conditions that produce phase shifts in a fixed-frequency reference signal.
48 Citations
25 Claims
-
1. Measurement apparatus comprising:
-
means for providing first and second signals of constant frequency and phase;
means for producing a phase shift in said first signal proportional to a phenomenon, property, or condition to be measured;
means for combining said phase-shifted first signal with said second signal to extract a third signal at a difference-frequency between the first and second signals; and
phaselocked loop means for producing an output signal phaselocked to said third signal, wherein phase changes in said third signal produce phase changes in said phaselocked loop output signal that are substantially greater than corresponding phase changes in said third signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
- 15. A measurement method in which a phenomenon, property, or condition to be measured produces phase changes in a fixed-frequency reference signal to produce a phase-shifted reference signal, and in which the phase-shifted reference signal is employed to produce corresponding, but substantially greater phase changes in another signal, that produces an output.
-
23. Apparatus for measuring a phenomenon, property, or condition that produces minute phase shifts in a fixed-frequency reference signal, comprising:
a system that uses the phase-shifted reference signal to produce a further signal in which the phase shifts of the phase-shifted reference signal are multiplied to a different order of magnitude and that produces an output from the further signal. - View Dependent Claims (24, 25)
Specification