(2) As audiotape moves across the recordhead, molecules on the tape orient themselves with
the direction of a magnetic field. The magnetic field is directly proportional to the audio signal being
fed to the record head. This audio signal reaches the tape from the record head with unnecessary
distortion or quality loss by a carrier signal commonly referred to as the bias.
d. Electronics. Because nonlinearity is a normal characteristic of magnetic tape used for
recording sound, the transfer of the audio signal from the record head onto the magnetic tape is not in
direct proportion and results in severe distortion of the signal (fig 3-33).
Figure 3-33. Bias current applied to audio signal