Jaime Martinez Monique Jones PAUL JACOB Ham Radio Amateur Radio The use of designated radio frequency spectra for purpose of private recreation noncommercial exchange of messages wireless experimentation self training and emergency communication ID: 346631
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1.5. CW (Morse Code) Decoding at Poor SNR
Jaime Martinez, Monique Jones, PAUL JACOBSlide2
Ham Radio (Amateur Radio)
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). Slide3
In the news…Slide4
CW (Morse Code)
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.Slide5
Problem
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.Slide6
Proposal
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.Slide7
Constraints
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).Slide8
WBS and TimelineSlide9
Budget
Net Cost : $0.00No additional resources required.Hardware FlexRadio Systems has already provided a radio.Software
Matlab is provided by Texas State University – San Marcos.Slide10
Conclusion
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).