Western Electric
22E SPEECH INPUT EQUIPMENT
Typical Characteristics
Maximum Gain
Frequency Response
Operates From
Operates Into
Signal-to-Noise Ratio
(Unweighted)
Distortion
Mixer Controls
Master Control
Power Supply
Power Required
AC Operation
Batteries
Approximately 90 db.
Uniform over the range from 35 to 10,000 cycles. See
curve, Figure 1.
30 ohm microphones or other 30 ohm circuits of com
parable level.
Output Pad of 150 or 600 ohms, selectable by screw
driver operated switch, for feeding telephone lines.
65 db for Battery Operation
�
Both at 70 db net gain
and referred to output
62 db for AC Operation
signal of +18 dbm.
Approximately 0.2'J'o at +8 dbm, 1.5% at +18 dbm.
See curve, Figure 2.
Four parallel mixers of 30 ohms each. Each mixer has
20 steps with a total of 45 db attenuation, and an OFF
position. The first 12 steps from minimum attenuation
have I
If:!
db attenuation each, the last 8 steps have
gradually increasing attenuation to OFF.
Twenty steps and OFF position. The first 17 steps from
minimum attenuation are 2 db each, increasing on
last 3 steps to OFF.
See Text.
Approximately 28 watts from nominal 115-volt,
50- or 60-cycle supply.
See Section on "Accessories".
Instruction Bulletin No. 1175, Issue No. 1
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