 Falsing sometimes occurs on a voice circuit when a human voice hits the exact pitch to which the tone decoder is tuned, a condition called "talk-off".For the tone decoder to work reliably, the audio input level must be in the linear range of audio stages, (undistorted).A 1,500 Hz tone fed into an amplifier that distorts the tone could produce a harmonic at 3,000 Hz, falsely triggering a decoder that is tuned to 3,000 Hz.