There is a study from 1992 that tested recognition rate vs pitch frequency. Unfortunately only a few tones were tested, but at least one can infer that a low tone is preferrable. This is in Montnemery, Peter, Bengt Almqvist, and Sten Harris. "Recognition of telegraphy signs at different listening levels and frequencies." Scandinavian Audiology 21.4 (1992): 255-260.
The abstract is: "The recognition of telegraphy masked by noise at 40 and 80 signs/min telegraphy speed was studied in 10 normal-hearing subjects at different sound pressure levels (25–85 dB SPL in steps of 5 dB) as well as at different test frequencies (2000, 1000, 800, 630, 500 and 250 Hz). The ability to recognize the signs varied with varying SPL. Recognition for most of the subjects was best at an SPL close to 70 dB. All subjects improved their recognition as the frequency was lowered to 500 Hz, some even at 250 Hz. These facts should be taken into consideration when training telegraphy operators as well as in the construction of radio receivers to permit listening at low frequencies. Furthermore, the critical ratio was calculated at the different test frequencies. Read More: http://informahealthcare.com/doi/abs/10.3109/01050399209046009"; Based on this result, it would be interesting to zoom in on the frequencies between 250 and 500 Hz for further testing, also higher speeds would be interesting to test as 40 and 80 is the same as 8 and 16 wpm. Peter Montnemery is by the way SM7CMY. ----- Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html -- View this message in context: http://elecraft.365791.n2.nabble.com/CW-Pitch-Resolution-tp7579837p7580032.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
