Energy Spectra for Frequency-Shift-Keyed Signals Transmitted by Synchronously Resonated, Very Low Frequency Antennas

Abstract

Electronic broadbanding is a technique whereby very low frequency (VLF) antennas can be resonated (retuned) synchronously with a frequency-shift- keyed (FSK) signal for transmission of binary data at rates well over 1000 baud. The thesis investigates the transmitted energy density spectrum for an electronically broadbanded VLF antenna system in which a frequency shift can occur only at the instant of an antenna-current zero-crossing with positive slope. A computer solution shows that the transmitted spectrum is approximately equivalent to the spectrum of an ideal, constant amplitude, FSK signal. A further investigation, again by computer program, shows that if the total frequency shift between the marking and spacing frequencies occurs over a finite period, rather than instantaneously, then the spectrum's sidelobes will be reduced significantly.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1973
Accession Number
AD0777268

Entities

People

  • Tee R. Hadley Iii

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • Energy and Power Technologies
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Air Force
  • Amplitude Modulation
  • Band Spectra
  • Computer Programs
  • Differential Equations
  • Electrical Engineering
  • Electromagnetic Fields
  • Frequency Modulation
  • Frequency Shift
  • Modulation
  • Modulators
  • Power Spectra
  • Resonant Circuits
  • Resonant Frequency
  • Silicon Controlled Rectifiers
  • Stochastic Processes
  • Very Low Frequency

Fields of Study

  • Engineering
  • Physics

Readers

  • Phased Array Antenna Design.
  • Radio communications and signal processing.

Technology Areas

  • Microelectronics
  • Space