The use of designated radio frequency spectra for purpose of
private recreation, non-commercial exchange of messages, wireless
experimentation, self training, and emergency communication. Though
a hobby for many, ham radio has been used effectively in times of
crisis and natural disasters as a means of emergency communication
when wireline, cellphones and other conventional means of
communications fail recent examples being 9/11, 2003 blackout,
Hurricane Katrina, and the Nepal Earthquake. Established by the
International Telecommunications Union (ITU).
Slide 4
Slide 5
A method of transmitting text as a series of on-off tones,
lights or clicks that can be interpreted by a trained
listener/observer. Introduced by Samuel Morse in 1836, but slight
changes were made & International Morse Code gained popularity
after 1848. Still used in the Ham (amateur radio) world for
recreation and emergency communication. Still remains the simplest
and most efficient way known to send messages via radio.
Slide 6
Write a program to decode multiple Morse code (CW) signals to
live text output automatically from a noisy RF band amidst a
varying noise floor (poor SNR) in real time using Digital Signal
Processing methods to isolate CW signals.
Slide 7
Receive and read the input audio. Perform a Short-term Fourier
Transform (SFT) to the audio file. Identify peaks in the magnitude
spectrum via zero-crossings. Filter signals using a Bandpass
filter. Perform automatic gain control (AGC). Demodulate and decode
the audio signal to text using a look up table with ensemble
search.
Slide 8
Manufacturability: Program should be compatible with existing
systems, and work in varied environments under different conditions
(noise, input, type of audio file, Morse speed, etc.) Ethical: Use
of public-domain open source code in functions and macros that are
implemented in project. Use of licensed software and developmental
tools. Sustainability: Program should be judicious with resource
utilization, and be efficient with processing power. Portability is
a desired trait, with hardware application kept in mind (ability to
port code to C or other language).
Slide 9
Slide 10
Net Cost : $0.00 No additional resources required. Hardware
FlexRadio Systems has already provided a radio. Software Matlab is
provided by Texas State University San Marcos.
Slide 11
Morse Code still remains relevant today, nearly 180 years after
its inception with marked use in emergency transmissions, providing
fast, inexpensive and efficient communication over long distances.
This program seeks to simplify the learning curve for amateur radio
operators unfamiliar with Morse code, enabling them to enjoy its
several benefits. Possible implementation as an added feature in
FlexRadio Systems software defined radio systems (SDRs).