The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 13, 1997
Filed:
Jul. 10, 1995
Thomson-CSF, Paris, FR;
Abstract
An N-bit analogue-to-digital converter can increase the resolution by 3 bits, by very precise coding of the differential phase at the output of the electro-optic phase modulator controlled by the electric signal to be converted. The optical signals obtained are processed by an electro-optic device that outputs electric signals that are functions of the sine and cosine of the phase. A coding device uses the symmetry of the trigonometric circle partitioned into four consecutive sectors between 0 and 27.pi. in order to convert the absolute values of the electric signals obtained on (N-3) bits, independently of the home sector of the phase. A transcoding device uses the value of the sine and cosine coded on (N-3) bits, to output a value V of the electric signal, on N bits, as a function of the home sector. The conversion system according to the invention comprises a first N-bit analogue-to-digital converter doing a very precise but ambiguous conversion of the electric signal, and a second analogue-to-digital converter to eliminate the ambiguity.