Welch Allyn GSI 38, Service Manual

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Pneumatic Svstem
Pressure Range (corrected for altitude): + 200 to 400 dapa (1 dapa = 1.02 mm
water)
Pressure sweeps to at least -100 dapa if tymps complete otherwise sweeps to -400
daPa
Pressure Accuracv: +/- 15% or +/- 10 daPa whichever is greater.
Rate of Sweep: 600 daPa/sec for tymp slopes of <0.2 ml per 24 daPa
200 daPa/sec for tymp slopes =,> 0.2 ml per 24 daPa
Test Time
Approximately 1 sec (high relative tymp will take longer).
Direction of Sweep:
Positive to Negative
ACOUSTIC REFLEX ACTIVATING STIMULUS SYSTEM
Stimulus Frequencies: 500, 1000, 2000, and 4000 Hz
Stimulus Freauencv Accuracv: +/- 3%
Stimulus Total Harmonic Distortion:
Stimulus Output Levels:
<5% measured acoustically except at 4 khz
where speaker driving signal is measured
IPSI: 500, 4000 Hz 80, 90, 100 dB HL
1000, 2000 Hz 85, 95, 105 HL
(Time multiplexed with probe tone, 106 ms On/53 ms Off Cycle)
CONTRA: 500, 1000, 2000 and 4000 HZ 90, 100, 110 db HL
(Steady tone, non multiplexed)
Equivalent Hearing Threshold Levels, in DB SPL