Photonic Analog-To-Digital Conversion Using the Robust Symmetrical Number System
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Authors
Pace, Phillip E.
Avizo, Mylene R.
Calusdian, James
Luke, Brian
Hollinger, Kenneth B.
Subjects
Advisors
Date of Issue
2012-09-18
Date
Publisher
The Government of the United States of America, as represented by the Secretary of the Navy, Washington, DC (US)
Language
en_US
Abstract
Embodiments in accordance With the invention allow for direct digitization of Wideband RF signals Without the need for down conversion or the use of mixers. In one embodiment, a preprocessed input analog signal is applied to three Wideband Mach-Zehnder interferometers (MZI), e.g., modulators, to amplitude modulate a continuous Wave laser signal. A photodetector is used at the output of each interferometer to convert the amplitude modulated optical signal into an electrical signal. This is followed by an amplifier and a low-pass filter (LPF) to increase the signal level and to reduce the noise. A small ml- comparator bank at the output of each LPF is clocked at the sampling frequency and encodes the electrical signal from each detector into a thermometer code that represents an integer value Within the modulus. A field programmable gate array (FPGA) then combines the thermometer code from each comparator bank in order to generate a more convenient 6-bit binary representation, i.e., a digital output.
Type
Patent
Description
Series/Report No
Department
Organization
Naval Postgraduate School (U.S.)
Identifiers
US 8,269,658 B1
NPS Report Number
Sponsors
Funder
Format
Citation
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.