초록 ▼

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

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.

대표청구항 ▼

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

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.