Rounding Results
The user needs to be aware that the SNR and single PASS criterion
on the Corti are calculated from the full internal precision of the
instrument, and not from the values shown in the printout for the
emission (DP/TE) and noise floor (NF) estimates.
This approach is used to preserve the full precision of the test results,
but can result in some apparent errors in the printout due to the effects
of rounding. Assume the actual values at a given frequency was DP
= 5.5 dB, NF = -0.4 dB, which results in SNR = 5.9 dB. The printout
values are rounded up to the nearest integer and are shown as DP =
6, NF = 0, and SNR = 6. This can result in what appears to be an error
with regard to the pass criterion. If the pass criterion is 6 dB while the
actual SNR is 5.9, the printed value will be 6 but the frequency will
not be judged as a PASS with a “P” printed.
Again, the pass/refer criterion is based on the full precision of the
results, and not the rounded values that are printed. The full precision
value for the SNR must be equal to or greater than the pass criterion
(6 dB in this example) for the “P” to be printed. To view precise
results, it is recommended that the test results be transferred to the
Data Manager where numeric test results are displayed with an
additional decimal place.
