Audioscan Verifit - Manual (Page 46)

Verifit ® User's Guide Version 3.12  May 2015
The OSPL90 curve, the HFA (or SPA) and peak value of this curve, the frequency of the peak, the HFA (or
SPA) full-on gain are determined at full-on gain setting. The response curve, frequency range, Reference Test
Gain, battery drain, equivalent input noise, distortion, attack and release times are determined at RTS.
These changes result in more consistent values for reference test gain, equivalent input noise and attack and
release time. See 1996 or 2003 ANSI standard, 8.2: ANSI S3.22-1996 facts and 8.5: ANSI 2003 Linear and
AGC tests.
ANSI 1996 Linear and AGC tests
1. Press , then highlight and [Test box measures], then highlight and [Linear] or
[AGC].
2. Highlight and [Start test] and follow the test setup instructions which are presented.
3. Refer to Test Box Measures – Setup, Coupling the hearing instrument, Positioning the hearing instrument
and Battery pill use and care to prepare the instrument for testing.
4. Turn the instrument ON.
5. Set the gain control (manual or programmable) to maximum with all other controls set to provide the widest
frequency response, greatest gain and highest maximum output. AGC controls and/or programmable
parameters should be set as designated by the manufacturer.
6. Press to run the test or to abort the test. Note that, if required, the Verifit will pause
during the test to request that the volume control be adjusted to the Reference Test Position (RTP). Open the
test box if necessary and, without moving the hearing instrument, adjust the user gain control until the large
vertical arrow on the screen prompt disappears. Press to resume the test.
If you are unsure which test sequence to run, try [AGC] first. If attack and release times are all near zero, the
instrument is probably linear.
ANSI 2003 Linear and AGC tests
1. Press , then highlight and [Test box measures], then highlight and [Linear] or
[AGC].
2. Highlight and [Start test] and follow the test setup instructions which are presented.
3. Refer to Test Box Measures – Setup, Coupling the hearing instrument, Positioning the hearing instrument
and Battery pill use and care to prepare the instrument for testing.
4. Turn the instrument ON.
5. Set the gain control (manual or programmable) to maximum with all other controls set to provide the widest
frequency response, greatest gain and highest maximum output. AGC controls and/or programmable
parameters should be set to minimize AGC action (AGC off or threshold high, compression ratio close to 1).
6. Press to run the test or press to abort the test. Note that, if required, the Verifit will
pause during the test to request that the gain control be adjusted to the Reference Test Setting (RTS). If
necessary, open the HIT chamber and, without moving the hearing instrument, adjust the gain control until
the large vertical arrow on the screen prompt disappears. Press to resume the test.
During the AGC test, the Verifit will pause to request that AGC controls or programmable parameters be set for
maximum AGC effect. If the manufacturer does not provide settings to produce maximum AGC effect, use
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