One of the sounds in my first soundpack for xonotic (http://xonotic. Org). Synthesized with zynaddsubfx inside lmms, edited in audacity. Long live linux!.
Sine signal of 1000hz generated to -20db of peak with a duration of 1 second to 25 frame/sec (pal (europe, uruguay, argentina, australia), secam, dvb, atsc).
I made this as a near ultrasonic sms signal. Created and edited with audacity, filtered with glame bandpass filter. If you hardly cut a pure tone, you introduce a whole lot of other frequencies to the signal at the cutting point. To avoid this after the cutting you need to filter the whole thing with a bandpass filter to ensure you have as little other frequency content as possible. It will audibly soften the start and the end of the sound. That's what i did here.
