Northern Airborne Technology AA23 User Manual

SM23

AA23

Speaker Amplifier

INSTALLATION AND OPERATION MANUAL

REV 4.00 November 21, 2003

Northern Airborne Technology Ltd.

1925 Kirschner Road

Kelowna BC, Canada

V1Y 4N7

Telephone [phone]

Facsimile [phone]

Copyright 2003 by Northern Airborne Technology

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM23 Rev. 4.00 AA23 Speaker Amplifier Manual

Performed at factory

Periodically NAT will release manual amendments. In order to maintain the most
accurate and up to date manual these amendments should be carried out immediately
upon receipt and recorded on the following amendment record.

AMENDMENT RECORD

Amendment

Number

Amendment

Date

Section(s)

Changed

Date

Entered

Entered By

809-0001 Oct 29,2004 2 Oct 29,2004

Nov 21, 2003 Page ii

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Insert any Amendment Instruction sheets after this page.

INSTALL_OPS MANUAL
AMENDMENT

Manual: SM23 (AA23) Amendment #: 1
Document # SM23\Install_Ops\809-0001 Amendment Date: Oct 29, 2004

The purpose of this amendment is to add the most recent drawings to the installation
section of the manual.

Amendment Instructions:

1 Remove Pages Replace With Pages

2-3 Rev. 4.00 2-3 Rev. 4.00 Amendment #1

2 Remove Drawings (Section 2) Replace or add Drawings (Section 2)

- AA23\922-0 Rev. 1.30

Note: Ensure that all drawings are inserted in the order shown on the latest drawing lists.

3 Update the Amendment Record sheet at the front of the manual.

4 Insert this page into the manual after the Amendment Record sheet (page ii).

Manual Amendment ends after the following amended pages

Amendment # 1 Oct 29, 2004 Page 1

ENG-FORM: 809-0108.DOT

PROPRIETARY AND CONFIDENTIAL TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM23 Rev. 4.00 AA23 Speaker Amplifier Manual

Table of Contents

Section Title Page

1.0 Description

1.1 Introduction 1-1

1.2 Purpose of Equipment 1-1

1.3 Features 1-1

1.4 Specifications 1-2

1.4.1 Electrical Specifications 1-2

1.4.2 Physical Specifications 1-3

1.4.3 Environmental Specifications 1-3

1.5 Accessories Required but not supplied 1-3

1.6 Unit Nomenclature 1-4

2.0 Installation

2.1 Introduction 2-1

2.2 Unpacking and Inspection 2-1

2.3 Installation Procedures 2-1

2.3.1 Warnings 2-1

2.3.2 Cautions 2-1

2.3.3 Notes 2-2

2.3.4 Cable and Wiring 2-2

2.3.5 External Components 2-2

2.3.6 Post-Installation Checks 2-2

2.4 Continued Airworthiness 2-3

2.5 Installation Drawings 2-3

3.0 Operation

3.1 Introduction 3-1

3.2 General 3-1

3.3 Performance 3-1

Nov 21, 2003 Page iii

ENG-FORM: 820-0109.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

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.

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AA23 Speaker Amplifier Manual SM23 Rev. 4.00

An internal trimpot is provided to permit level adjustment of the over-all system. As
shipped, range remains in both directions, up and down.

A set of uncommitted relay contacts (2 A rating) is provided that is closed when the unit
receives a mute command (key ground input). This can be used for external switching.

Fully muted (no output) and partially muted outputs are available to provide a choice of
enabled or disabled speaker sidetone. The muting circuit inserts a 44 Ω resistor in
series with the load, to reduce the output level.

Two external, unrelated key inputs can mute the AA23, and both provide a flow-through
key output to other systems. This permits two users in a close cockpit installation to
mute each other's speakers to prevent feedback, and provides outputs to the balance of
the audio system for TX keying.

The headset input places a greater than 1.8 kΩ load on the existing headset driver
system, which represents a negligible load. It is a fully floating input, and will not
introduce any ground loop interference unless grounded via the user interconnect. This
line is meant for signals of typically +17 dBm to +20 dBm (50 mW/600 Ω).

The 600 Ω line input can be used with lower level sources to provide a speaker buffer
as needed. Input sources can be music, radio feeds (via a pad) or other sources. Note
that this connection is the direct input to the AA23 transformer, and is isolated from the
headset input only by a simple resistive pad. Signals injected here may appear back at
the headset input, and cause problems if isolation was intended.

The mic input accepts a ‘carbon-equivalent’ unit, and has internal excitation from the
AA23. The input is floating, and must have a ground at the input low connection to
excite the microphone. This is normally provided by any NAT audio system if used to
provide the mic input (PA position).

1.4 Specifications

1.4.1 Electrical Specifications

Input Power +22 to 32 Vdc.

Supply Current 1.0 A max. (at full output into 3.2 Ω).

0.3 to 0.5 A (typical)

Input Levels

600 Ω input 0.45 Vrms (-5 dBm) at 1 kHz.

H/S Input 7.70 Vrms (+20 dBm) at 1 kHz.

Mic Input 0.25 Vrms at 1 kHz.

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SM23 Rev. 4.00 AA23 Speaker Amplifier Manual

Output Levels

3.2 Ω Load 9.0 Wrms @ 1 kHz with <0.6% distortion.

4.0 Ω Load 7.5 Wrms @ 1 kHz with <0.6% distortion.

8.0 Ω Load 4.5 Wrms @ 1 kHz with <0.5% distortion.

16 Ω Load 2.5 Wrms @ 1 kHz with <0.3% distortion.

Input Logic Key inputs are active LOW (GND = MUTED).

Output Logic Key outputs are diode isolated and track their

respective inputs less a 0.7 V diode drop.

1.4.2 Physical Specifications

Height 1.73 in (43.8 mm) including top heatsink.

Depth 5.20 in (132.1 mm) excluding connector. Allow

5 cm clearance for cable and connector.

Width 3.95 in (100.3 mm) including mounting flange.

Weight 0.78 lb (355 g) less mating connector.

Mounting 4 x 10-32 mounting bolt/screw.

Mounting Hole Centers 3.60 in (91.4 mm) by 3.45 in (87.6 mm).

1.4.3 Environmental Specifications

Temperature -20° C to + 65° C.

Altitude 15,000 ft. max.

Humidity 95 % Non-Condensing.

Shock 12 g. (any axis)

1.5 Accessories Required but not Supplied

Installation kit p/n AA23-IKC (crimp) or AA23-IKS (solder) is required to complete the
installation. They consist of the following:

AA23-IKC 15 Pin D-min Female Crimp Kit (NAT Part # D15SL-IKC)

Quantity Description NAT Part #

1 D-min 15 Socket Housing 20-21-015
15 MS Crimp Socket 20-26-901
1* Jack Screw Set 20-27-002
1* Lock Clip Set 20-27-004
1 15 Pin Connector Hood 20-29-015

* Use as required.

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ENG-FORM: 800-0106.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

AA23 Speaker Amplifier Manual SM23 Rev. 4.00

AA23-IKS 15 Pin D-min Female Solder Kit (NAT Part # D15SL-IKS)

Quantity Description NAT Part #

1 D-min 15 Socket Solder Cup 20-20-015
1* Jack Screw Set 20-27-002
1* Lock Clip Set 20-27-004
1 15 Pin Connector Hood 20-29-015

* Use as required.

1.6 Unit Nomenclature

Model Description / Distinction

AA23-001 Accepts Mic., 600 Ω Line and H/S inputs, with floating interface.
Muted or partially muted outputs.
Dual PTT key logic inputs and outputs.
Selectable frequency response, Voice or Music.
Adjustable gain.

AA23-002 Accepts Mic. and two H/S inputs, with floating interface.
Muted or partially muted outputs.
Dual PTT key logic inputs and outputs.
Selectable frequency response, Voice or Music.
Adjustable gain.

End of section 1.0

Page 1-4 Nov 21, 2003

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