MagTek InSpec 9000-2005 - Manual (Page 61)

Appendix A. Magnetic Encoding
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After recording a magnetic tape with this increasing current, as shown above, we can then Read
the signal amplitude peaks and plot the peak values as a function of the encode current level.
The resulting plot is shown in Figure A-7.
Figure A-7. Signal Amplitude
This plot is known as the magnetic tape’s saturation characteristic. Notice that the Signal
Amplitude increases linearly as the encode current increases until it reaches a maximum value
where afterwards the Signal Amplitude decreases slowly with ever increasing encode current.
The maximum value of Signal Amplitude on this plot is called the saturation point of the
magnetic tape.
As a point of interest, the region of the magnetic tape’s saturation characteristic, before
saturation is the region where audio or sound recordings take place. That is, audio recorders
limit the amount of recording current so that when loud passages are recorded, the playback
signal amplitude is the greatest while quiet passages generate small currents and yield small
levels of signal amplitude. Digital recordings utilize the region after the saturation point. We
will continue this discussion in the next section on Digital Magnetic Recording.