Calibration Properties - Interacoustics AT235 Service Manual

Service Manual
AT235
6.1

Calibration properties

Calibrated transducers:
Accuracy:
Stimulus presentation
control:
Impedance calibration properties
Probe tone:
Compliance:
Pressure:
Barometric pressure:
Height above sea level:
Contralateral earphone:
Probe system:
General:
Reflex Frequencies:
Contralateral reflex and
audiometer tone levels:
Ipsilateral reflex tone
levels:
Pressure measurement:
Compliance
measurement:
Reflexes:
Frequencies:
Level:
Distortion:
Range:
Temperature
dependence:
Pressure dependence:
Reflex sensitivity:
Reflex artifact level:
Temporal reflex
characteristics:
(IEC60645-5 clause
5.1.6)
Range:
Safety limits:
The barometer pressure
chances influence on the
impedance measurement
in the specified range
(97300 – 105300
Pascal).
The pressure sensor used, is a differential/gauge type, which means, it measure the
pressure difference and therefore not affected of the height above sea level.
Probe tones 0 meters
226 Hz 1.0 mmho
678 Hz 3.0 mmho
800 Hz 3.54 mmho
1000 Hz 4.42 mmho
Telephonics TDH39/DD45 with a static force of 4.5 N 0.5
N and/or EARtone 3A and/or CIR insert phone
Ipsilateral Earphone: is integrated in the probe system
Probe frequency transmitter and receiver and pressure
transducer is integrated in the probe system
Generally the instrument is made and calibrated to be
within and better than the tolerances required in the
specified standards:
±1%
3 dB for 250 to 4000 Hz and 5 dB for 6000 to 8000 Hz
5 dB for 500 to 2000 Hz and +5/-10 dB for 3000 to 4000
Hz
5% or 10 daPa, whichever is greater
5% or 0.1 ml, whichever is greater
ON-OFF ratio ≥ 70 dB
Rise time = 20 ms
Fall time = 20 ms
A weighted SPL in Off = 31 dB
226 Hz 1%, 678 Hz 1%, 800 Hz 1%, 1000 Hz 1%
85 dB SPL 1.5 dB measured in an IEC 60318-5
acoustic coupler. The level is constant for all volumes in
the measurement range.
Max 1% THD
0.1 to 8.0 ml
-0.003 ml/C
-0.00020 ml/daPa
0.001 ml is the lowest detectable volume change
≥95 dB SPL (measured in the 711 coupler, 0.2 ml, 0.5 ml,
2.0 ml & 5.0 ml hard walled cavities)
Initial latency = 35 ms (5 ms)
Rise time = 42 ms (5 ms)
Terminal latency = 23 ms (5 ms)
Fall time = 44 ms (5 ms)
Overshoot = max. 1%
Undershoot = max. 1%
Values between -600 to +400 daPa can be selected in the
setup.
-750 daPa and +550 daPa, 50 daPa
Admittance can vary inside: ± 4%
The pressure accuracy is: ±10 daPa or 10%, whichever is
greater
500 meters 1000 meters
1.06 mmho 1.13 mmho
3.19 mmho 3.40 mmho
3.77 mmho 4.01 mmho
4.71 mmho 5.01 mmho
2000 meters 4000 meters
1.28 mmho 1.65 mmho
3.85 mmho 4.95 mmho
4.55 mmho 5.84 mmho
5.68 mmho 7.30 mmho
III