Selecting the Averaging Time
The Averaging Time can be changed to one of four settings. The
Averaging Time will have a significant impact on the time required
to perform the test and on the signal-to-noise ratio (SNR). An 8
second average would produce a test in about 8 seconds. A 64 second
average would produce a test in about 64 seconds. The possible
settings for the Averaging Time are as follows:
8, 16, 32, or 64 seconds.
The instrument will automatically stop the test when the pass criterion
is met prior to the averaging time. Press the
CHANGE
keys to
select an option and the
NEXT key to exit (Display 36).
Setting the PASS SNR Level
To provide a PASS/REFER determination for each test, the PASS
SNR must be set. This number refers to the number of decibels that
the TEOAE signal must be above the noise to be considered a PASS
at that frequency. The limits for the PASS SNR are 3 dB to 10 dB.
Pressing the
LEFT or RIGHT
arrow keys will increase or
decrease the requirement. This requirement is used in combination
with the number of frequencies (discussed below) to determine an
overall PASS/REFER for each test.
Press the
CHANGE
keys to select an option and the
NEXT
key to exit (Display 37).
Setting the Number of Frequencies for PASS
The number of frequencies for determining a PASS can be set from
0 to 6.
If the setting is on 0, then no indication of PASS/REFER
will be made.
This setting is used in conjunction with the PASS SNR
to set the criteria for the overall test PASS/REFER indication. For
example, if the PASS SNR is set to 4 dB and the number of
frequencies for PASS is set to 3 then the test must contain at least 3
frequencies where the emission is at least 4 dB above the noise to
indicate a PASS.
Press the
CHANGE
keys to select an option and the
NEXT
key to exit (Display
38
).
Display 36
Display 6
Display 38
