Processing of the manual morse signal using optimal linear filtering, smoothing and decoding
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Authors
Bell, Edison Lee
Subjects
Morse code
Kalman filter
linear smoothing
Viterbi decoder
Kalman filter
linear smoothing
Viterbi decoder
Advisors
Jauregui, S.
Date of Issue
1975-09
Date
September 1975
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
This thesis investigates the problem of automatic transcription of the Morse signal, and describes and documents several approaches to filtering, processing and decoding it for transcription. The baseband signal is first modeled as a modified random telegraph wave. A discrete Kalman filter and a linear smoother are then used to process the demodulated signal in order to gain a measure of the effectiveness and applicability of this model. It is shown experimentally that this model and processing yield a significant reduction in the transcription error rate. Next a Viterbi decoder algorithm based on a simple Markov model of the code is incorporated in a more general model for pre-detection Kalman filtering. It is shown that this filter permits acceptable recovery of Morse signals whose average signal-to-noise ration is as low as -14 dB in a 3 kHz bandwidth.
Type
Thesis
Description
Series/Report No
Department
Department of Electrical Engineering
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
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.