Northern Airborne Technology AA23 - Manual (Page 9)

SM23 Rev. 4.00 AA23 Speaker Amplifier Manual
Section 1.0 Description
1.1 Introduction
This manual contains information on the AA23 Speaker Amplifier.
Information in this section consists of purpose of equipment, features and specifications.
1.2 Purpose of Equipment
The AA23 is a versatile speaker amplifier that can be used to convert balanced 600 Ω
line, 150/600 Ω headset, or carbon-equivalent microphone levels to speaker outputs.
The interface to the AA23 is fully floating (transformer coupled), permitting complex and
long distance interconnects and providing outstanding rejection of ground loop signals.
The speaker output is ground referenced.
The AA23 can be used for distributed music systems, paging, transfer of headset based
systems to speaker based outputs, or as a very high powered headset booster driver.
The output of the AA23 can be selected ON or OFF by a simple logic line (GND =
muted) to simplify external wiring in most applications.
Extensive key logic and muting capability is also incorporated into the AA23, which
addresses close cockpit installations, and provides some extra flexibility in difficult
installations. Either fully muted or partially muted installations can be accomplished
through interconnect pin selection.
The AA23 will drive any speaker load from 3.2 to 16 Ω, but provides optimum energy
transfer into either 4 or 8 Ω loads. If operated continuously with a high average power
level, the unit must have air exchange for the heat sink assembly to function properly.
1.3 Features
The AA23 incorporates a power (and fuse) monitor LED that allows in-place visual
indication of unit activity. The LED will turn off if either the external breaker or internal
fuse is tripped.
The AA23 incorporates an internal noise filter to eliminate DC coupled interference into
the system.
To provide a choice of bandpass operation (voice or music), the AA23 has an internal jumper
selection. With the jumper installed, the bandpass is slightly reduced to provide better voice
performance and improved feedback reduction. With the jumper removed, wide band music
operation can be achieved. The units are shipped with the jumper installed.
Nov 21, 2003 Page 1-1
ENG-FORM: 800-0106.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.