MagTek InSpec 9000 - Manual (Page 35)

Section 3. Operation
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The value of the reference signal amplitude is traceable to the Primary Standard as established
by the United States National Institute for Standards and Technology (NITS), formerly the
National Bureau of Standards. Figure 3-12 shows the reference amplitude and the related
boundaries for within spec, marginal, or out of spec. These values as well as the values for the
other parameters below are listed in Appendix C (from 7811). Composite values (from 7811-2
and 7811-6) are listed in the ISO Limits under the View Menu.
Figure 3-12. Reference Amplitude
Bit Size
The bit size, or bit cell, is the distance between two clocking flux transitions. This distance is the
“zero” bit. The ISO standard abbreviates the bit size as Bin and calls it Individual Flux
Transitions Spacing Variation. Figure 3-13 shows the bit size, the subinterval, the adjacent bit
and the adjacent subinterval.
Sub. Int.
The Sub Int., or subinterval, is simply the distance of the bit cell divided by two. Two
subintervals form a “one” bit, shown in Figure 3-13 as Sin. The ISO standard abbreviates the
subinterval as Sin and calls it Subinterval Spacing Variation.