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This shows 4 clear PSK signals with a faint 5th PSK signal as well. Click here to hear a PSK 31 signal |  RTTY
This signal shows a RTTY signal. Click here to hear the signal.
This signal shows a 300 Baud Packet radio signal on HF. Click here to hear the signal.
This picturesl shows an AMTOR signal on 18M. Click here to hear the signal. 
This picture shows an Hellschreiber signal on 30 Meters, with a PSK signal on the left. The link above contains a number of interesting points about the origin of this mode during World War II to enable the German troops to "see" the messages coming across without knowing Morse code. Click here to hear the signal.
This illustrates a MFSK16 signal on 20 M. Click here to hear the signal. Throb
This illustrates a Throb signal on 10 M. Click here to hear the signal. Throb is yet another new Digital Signal Processing mode that attempts to use Fast Fourier Transform technology (as used by waterfall displays) to decode a 5 tone signal. The THROB program is an attempt to push DSP into the area where other methods fail because of sensitivity or propagation difficulties and at the same time work at a reasonable speed. The text speed is slower than other modes but the author (G3PPT) has been improving his MFSK (Multiple Frequency Shift Keying) program.
There are a number of other modes that I have signal sounds recorded but have not had time to place images: Slow Scan TV -- signals can almost always be found on 20 meters. Here is what it sounds like.Today most amateur operators send the images to and from their computer using the computers sound card. Pactor - Another networking technique for transfering files and e-mail via amateur radio. It sounds like this.
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