Output Hearing Level Controi; Signal To Noise Ratio; Tone Switch - Welch Allyn Grason-Stadler GSI 17 Series Service Manual

1.4 OUTPUT HEARING LEVEL CONTROL
CALIBRATED IN dB HL
MEASURED IN INCREMENTS OF 5 dB
RANGES
Hz
125
500 to
6000
250 and 8000 Hz
Additionally A
maximum HL at all frequencies by 10 dB.
ACCURACY OF ALL SETTINGS OF HEARING LEVEL CONTROL:
125 to 4000 Hz
6000 to 8000 Hz
1.5 SIGNAL TO NOISE RATIO (IN 1/3 OCTAVE)
dB measured acoustically in dB HL
>70

1.6 TONE SWITCH

electronic
This
minimal audible distortion.
MODES
Normal State:
Activated State:
RISE/FALL TIME
ms
20-50
Measured at the -1 dB and -20 dB points on the signal envelope.
ON/OFF RAT IO
With the Tone Switch OFF, the output will be at
below standard reference equivalent threshold for any 1/3
band with HL setting of 60 dB or below.
ABOVE 60 dB HL SETTING
dB
>70
CROSS CHANNEL LEAKAGE
At HL settings of 70 dB or greater, unwanted signals in the non-
test earphone shall be at least 70 dB below the tone in the test
earphone.
-10 to
Hz -10 to 90 dB B HL
-10 to 70 dB B HL
"+10 dB" " Extended Range
switch turns the stimulus
Stimulus OFF
Stimulus ON
dB B HL
50
Switch,
dB
signal
which
extends
ON/OFF with
least
-10 dB
octave