Naval Postgraduate School
Dudley Knox Library
NPS Dudley Knox Library
View Item 
  •   Calhoun Home
  • Theses and Dissertations
  • 1. Thesis and Dissertation Collection, all items
  • View Item
  •   Calhoun Home
  • Theses and Dissertations
  • 1. Thesis and Dissertation Collection, all items
  • View Item
  • How to search in Calhoun
  • My Accounts
  • Ask a Librarian
JavaScript is disabled for your browser. Some features of this site may not work without it.

Browse

All of CalhounCollectionsThis Collection

My Account

LoginRegister

Statistics

Most Popular ItemsStatistics by CountryMost Popular Authors

Time/frequency relationships for an FFT-based acoustic modem

Thumbnail
Download
Icon10Sep_Jenkins.pdf (932.5Kb)
Download Record
Download to EndNote/RefMan (RIS)
Download to BibTex
Author
Jenkins, William F.
Date
2010-09
Advisor
Rice, Joseph A.
Second Reader
Ziomek, Lawrence J.
Metadata
Show full item record
Abstract
5km) communications in the 9-14 kHz band. The proposed scheme exploits a higher carrier frequency at 45 kHz and increased spectral bandwidth compatible with the short-range link, thus achieving an increased channel capacity. Analytical expressions are provided for the scheme, which combines principles of M-ary frequency-shift keying (MFSK) and orthogonal frequencydivision multiplexing (OFDM) in a modulation referred to as multi-channel MFSK. The proposed scheme consists of 32 orthogonally spaced channels, each of which contains a 4-ary FSK pulse train. Existing medium-range modem algorithms are adapted for the higher carrier frequency and candidate variations are implemented with bandwidths of 10 and 20 kHz. The variations involve bandwidth scaling or multiplexing the original 5 kHz spectral bandwidth. Of concern for short-range links in shallow water is multipath interference, which causes time-spreading and significant intersymbol interference (ISI). Dominant eigenray paths are determined in order to estimate the amount of time-spread expected in various shallow water environments. These are analyzed with respect to the time/frequency relationships of multi-channel MFSK to comparatively evaluate the candidate variations in terms of protection against ISI. On this basis, we propose multiplexing the 5 kHz MFSK modulation across the larger operating band.
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.
URI
http://hdl.handle.net/10945/5205
Collections
  • 1. Thesis and Dissertation Collection, all items

Related items

Showing items related by title, author, creator and subject.

  • Thumbnail

    Climatological Factors Affecting Electromagnetic Surface Ducting in the Aegean Sea Region 

    Raptis, Konstantinos (Monterey, California. Naval Postgraduate School, 2012-03);
    We have studied the conditions that affect atmospheric electromagnetic surface ducts in the Aegean Sea region and how those conditions are related to regional and global scale climate variations. As a primary source for ...
  • Thumbnail

    A study of the diffraction behavior and resolution criteria for pattern recognition for a proposed multiplexed imaging technique 

    Musselman, Brian Jay (Monterey, California. Naval Postgraduate School, 1991-09);
    This project quantifies several aspects of a new multiplexed imaging technique proposed by D. S. Davis. The novel approach of this technique involved the use of encoding masks derived from a basin set of two-dimensional ...
  • Thumbnail

    Conceptual design and software simulation of a wideband leakage cancellation circuit 

    Ang, Teo Hong (Monterey, California. Naval Postgraduate School, 2010-12);
    The objective of this thesis is to investigate a Wideband Leakage Cancellation Circuit (WLCC) to facilitate potential improvement of range resolution in single antenna Frequency Modulated Continuous Wave (FMCW) radar, as ...
NPS Dudley Knox LibraryDUDLEY KNOX LIBRARY
Feedback

411 Dyer Rd. Bldg. 339
Monterey, CA 93943
circdesk@nps.edu
(831) 656-2947
DSN 756-2947

    Federal Depository Library      


Start Your Research

Research Guides
Academic Writing
Ask a Librarian
Copyright at NPS
Graduate Writing Center
How to Cite
Library Liaisons
Research Tools
Thesis Processing Office

Find & Download

Databases List
Articles, Books & More
NPS Theses
NPS Faculty Publications: Calhoun
Journal Titles
Course Reserves

Use the Library

My Accounts
Request Article or Book
Borrow, Renew, Return
Tech Help
Remote Access
Workshops & Tours

For Faculty & Researchers
For International Students
For Alumni

Print, Copy, Scan, Fax
Rooms & Study Spaces
Floor Map
Computers & Software
Adapters, Lockers & More

Collections

NPS Archive: Calhoun
Restricted Resources
Special Collections & Archives
Federal Depository
Homeland Security Digital Library

About

Hours
Library Staff
About Us
Special Exhibits
Policies
Our Affiliates
Visit Us

NPS-Licensed Resources—Terms & Conditions
Copyright Notice

Naval Postgraduate School

Naval Postgraduate School
1 University Circle, Monterey, CA 93943
Driving Directions | Campus Map

This is an official U.S. Navy Website |  Please read our Privacy Policy Notice  |  FOIA |  Section 508 |  No FEAR Act |  Whistleblower Protection |  Copyright and Accessibility |  Contact Webmaster

Export search results

The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

A logged-in user can export up to 15000 items. If you're not logged in, you can export no more than 500 items.

To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.