Phase difference detecting method, circuit and apparatus
US5495100A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 26, 1994 |
| Grant date | Feb 27, 1996 |
| Priority date | — |
| Expiry date | Jul 26, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R25/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In phase difference detecting method, circuit, and apparatus of the present invention, a voltage signal having a predetermined frequency is applied to a photoconductive light-receiving device, and an optical signal is received by this photoconductive light-receiving device. A current generated upon reception of light and flowing in the photoconductive light-receiving device reflects a product value of the voltage signal and the optical signal, and contains a DC component according to a phase difference between the voltage signal and the component of the optical signal having the same intensity modulation frequency as that of the voltage signal. A time average value of the current flowing in the photoconductive light-receiving device or a voltage value obtained upon conversion of this current is generated, and only the DC component is extracted, thereby detecting the phase difference between the voltage signal and the component of the optical signal having the same intensity modulation frequency as that of the voltage signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.