Operating Instruction
ERO•SCAN
®
Screening and Diagnostic Version
operating_instructions_8106556-6_EROSCAN_e_15a
36
8106556-5 02/15
15
Rounding Results
The user needs to be aware that the SNR and single PASS criteria are calculated from the
full internal precision of the instrument, and not from the values shown in the printout for
the emission (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. In the printout example
above, assume the actual values at 1.5 kHz were TE = 4.5 dB, NF = -0.4 dB, which results in
SNR = 4.9 dB. The printout values are rounded up to the nearest integer and are shown as
TE = 5, NF = 0, and SNR = 5. This can result in what appears to be an error with regard to
the pass criterion. If the pass criterion is 5 dB while the actual SNR = 4.9, the printed value
will be 5, but a “P” will NOT be 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 (5 dB in this example) for the “P” to be printed. A similar
apparent problem can occur in which the printed SNR value appears to be incorrect. If the
actual values were TE = 4.5 dB, NF = 0.4 dB, resulting in SNR = 4.1 dB, the printed values
would be TE = 5 dB, NF = 0, SNR = 4. The printed SN value of 4 dB appears to be an error,
but is in fact correct.
Summary of Contents for ERO SCAN
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