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Here are two demonstrations of the MX T-Tone oscillator in operation. The files are in MP3 format, approximately 250Kb in size. Your browser might play them automatically when you click on the links, or if not, you can right-click on the link, and save or "open" the file.
1. Straight key, a continuous tone followed by a series of Vs at about 18wpm. skey15.mp3
2. Electronic keyer, a continuous tone followed by Vs and my callsign at about 28wpm. keyer28.mp3
The wave shaping capability of the T-Tone makes this possible. With most code practice oscillators, the dots would be run together and distorted.
The recordings were made by placing a PC microphone (connected to the sound card's "mic" input) near the speaker of the T-Tone.
I did the straight key sending with a GHD GT-501 telegraph key, and the keyer sending with a Scheunemann Morse Dirigent paddle and Logikey K-5 keyer. I adjusted the T-Tone's wave shaping by ear before recording (you can certainly do that with a scope, but I was pleased to discover that my ear is nearly as accurate as the scope). The wave train image of the letter V at the top of the page is from the straight-key recording and is very similar to what I see on the scope-- it was produced by the sound editing program that did the recording and file conversion. When the wave train is not correctly adjusted for high speed code, the dots and dashes are elongated and run together.
The output from the T-Tone was captured as a PCM (wav) file which was converted to MP3. In the conversion, the wav files were compressed from around 12MB to around 250Kb. I didn't hear any appreciable difference in the sound quality. That said, the quality of reproduction could also be influenced by the equipment that you use to play it back. In particular, if you set the volume too high you will likely over-drive your speakers.
A similar test was conducted over a 2M repeater. The microphone was held open by hand, and placed near the T-Tone speaker. No adjustment of mic gain was done, and reports were that reproduction was actually better than the repeater's own Morse ident.