title: Performance of electronic Morse decoders in decoding telegraphy masked by noise.
abstract: The performance of five different electronic Morse decoders in decoding telegraphy signs (Morse code) consisting of 800 Hz pure tones masked by a narrow-band noise with a bandwidth of 185 Hz (1/3 octave 713-890 Hz) centred at 800 Hz and a broadband noise (100-2,500 Hz) was studied at 20, 40, 80, 150 and 200 signs/min telegraphy speed. In steps of 1 dB the S/N ratios were varied from high values where 100% was recognized to low values where nothing was recognized. At narrow-band masking noise with 80 and 150 signs/min telegraphy speed a S/N ratio varying from +8 to +12 dB and +8 to +11 dB respectively was required for 100% recognition. At broad-band masking noise the S/N ratios required for 100% recognition varied from -4 to +3 dB at 80 signs/min telegraphy speed and -3 to +3 dB at 150 signs/min telegraphy speed. When compared to earlier findings in our laboratory concerning human recognition of Morse signs it seems that man outperforms electronic Morse decoders at low S/N ratios and low to moderate telegraphy speeds (< 100 signs/min).
authors.affiliation: Department of Audiology, University Hospital, Lund, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Montnemery
authors.forename: B
authors.initials: B
authors.lastname: Almqvist
authors.forename: S
authors.initials: S
authors.lastname: Harris
mesh_terms: D001307:Auditory Perception; D004867:Equipment Design; D006801:Humans; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D013685:Telecommunications