Northern Airborne Technology 251 User Manual
Page 6
Model 251 Passenger Speaker Amplifier
SM251 Installation and Operation Manual
Section 1 Rev: 1.00
Issue 2
Page 1-3
ENG-FORM: 800-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
OUTPUTS:
Right Speaker:
The right speaker amplifier is designed for speech and music
signals.
Rated power specification is the maximum power the amplifier
can continuously deliver into the maximum rated load without
clipping.
Rated Power
Load
49 W
1 ohm (40 Watts typical)
28 W
2 ohms (30 Watts typical)
15 W
4 ohms (18 Watts typical)
Left Speaker:
Same as right speaker specification
Right Monitor:
Delivers up to 26 milliwatts into 600 ohms continuously. Factory
calibration is 1.6 mW (1 Vrms).
Left Monitor:
Same as right monitor specification
PA Sidetone:
6.7 milliwatts (2 Vrms) into 600 ohms continuous.
Rated and continuous power ratings are the same.
Chime Tone:
Generated and supplied to left and right speaker and monitor
outputs when 12 to 32 Vdc is applied to or removed from
connector pins P50-31 or P50-32.
A 790 Hz tone followed by a 610 Hz tone (2-tone, HI/LO) is
factory set for 3.5 VPP (at speaker outputs), adjustable from 1.0
to 6.9 VP-P and is also available at monitor outputs.
Ringer Tone:
Generated and supplied to left and right speaker and monitor
outputs when a ground signal is applied to connector pin P50-33.
Ringer tone is 700
±75 Hz tone, ON for 1.8 ±0.1 second, then OFF
for 3.2
±0.1second, repeating. Factory set for 1.5 VP-P (700 Hz
component) (at speaker outputs), adjustable from 0 to 5.2 VPP.
Frequency Response:
Upper and lower frequency limits are adjustable. Stereo, ADF,
TV, and PSC inputs to speaker and monitor outputs are flat
within 3 dB from 40 Hz to 20,000 Hz. All other inputs to speaker,
monitor, or PA sidetone outputs flat within 3 dB from 300 Hz to
6,000 Hz.
Harmonic Distortion (Thd+N):
Less than 0.30 percent distortion, for stereo and less than 1% for
ADF, TV and PSC to all outputs (40 Hz to 20 KHz). Less than
3% for PA and briefer to all outputs (300 Hz to 6 KHz).
Isolation Between Channels:
60 dB, minimum.
Output Noise:
Greater than 75 dB below rated, all outputs.