Audio signal generator with twirly knob. The frequency knob responds to finger twirling. The fine frequency and level sliders allow for fine adjustments of frequency and output level. The frequency knob is also adjustable using the left and right arrow buttons. The two bookmark buttons below the frequency knob show if there are bookmarks, and will go to the next lower or higher bookmark if it exists. * Frequency range 0.1Hz - 25KHz * Level range 0dB - -80dB * Set exact frequency * Frequency bookmarks