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:
Nov. 05, 2002
Filed:
Jul. 17, 2000
Allan Ward, Alexandria, VA (US);
Keith J. Williams, Accokeek, MD (US);
Paul D. Biernacki, Alexandria, VA (US);
Lee T. Nichols, Springfield, VA (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
An image rejecting microwave photonic downconverter uses a microwave sub-carrier modulation technique without concern for image frequency interference in the shifted signal, thereby allowing telecommunications systems to downconvert densely multiplexed communications channels into a low frequency band where conventionqal electronics can perform signal-processing functions. The image rejecting microwave photonic downconveter incoming microwave signals can be processed without ambiguity in direction finding applications, allowing remotable, multioctave microwave signal processing for frequency and phase determination. A first laser providing an optical carrier that is modulated by a first electro-optic modulator with a sinusoidal electrical signal generated by a first local oscillator and a second laser providing optical carrier that is modulated by a second electro-optic modulator with a sinusoidal electrical signal generated by the second local oscillator for a signal generated by a second local oscillator; are transmitted independently through two polarization-maintaining (PM) optical fibers of arbitrary length to a distant point. There the first modulated optical signal is converted to an electrical domain and mixed with an input from an ultra-broadband radio frequency (RF) antenna receive-array, shifting the entire RF band to a higher frequency band equal to the original RF signal plus the modulated optical frequency signal.