Nat 270 User manual

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM270

270

Universal Interface Amplifier

INSTALLATION AND OPERATION MANUAL

REV 4.10 Dec 12, 2006

Northern Airborne Technology Ltd.

1925 Kirschner Road

Kelowna, BC, Canada.

V1Y 4N7

Telephone (250) 763-2232

Facsimile (250) 762-3374

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Digitally signed by Barb Page

Date: 2020.02.12 11:25:07 -07:00

Reason: Certify Document

Location: Prescott Arizona, USA

These commodities, technology or software are controlled in accordance with the United States Export Administration Regulations, Export Classification

Control Number(ECCN) EAR99. When exporting, diversion contrary to U.S. law is prohibited.

SM270 Rev. 4.10 Model 270 Universal Interface Amplifier Manual

Dec 12, 2006 Page ii

ENG-FORM: 820-0110.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

Northern Airborne Technology Ltd.

has acquired the assets of dB Systems Inc.,

and has revised and reissued this manual in

standard NAT format.

Northern Airborne Technology Ltd.

will be responsible for all future

amendments and revisions.

These commodities, technology or software are controlled in accordance with the United States Export Administration Regulations, Export Classification

Control Number(ECCN) EAR99. When exporting, diversion contrary to U.S. law is prohibited.

These commodities, technology or software are controlled in accordance with the United States Export Administration Regulations, Export Classification

Control Number(ECCN) EAR99. When exporting, diversion contrary to U.S. law is prohibited.

SM270 Rev. 4.10 Model 270 Universal Interface Amplifier Manual

Dec 12, 2006 Page iii

ENG-FORM: 820-0110.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

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

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Insert any Amendment Instruction sheets after this page.

Consult NAT for any questions regarding product revisions prior to

SM270 Revision 4.10.

These commodities, technology or software are controlled in accordance with the United States Export Administration Regulations, Export Classification

Control Number(ECCN) EAR99. When exporting, diversion contrary to U.S. law is prohibited.

These commodities, technology or software are controlled in accordance with the United States Export Administration Regulations, Export Classification

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SM270 Rev. 4.10 Model 270 Universal Interface Amplifier Manual

Dec 12, 2006 Page iv

ENG-FORM: 820-0110.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

Table of Contents

Section Title Page

1 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 1-5

1.4.3 Environmental Specifications 1-5

1.5 Unit Nomenclature 1-5

2 Installation

2.1 Introduction 2-1

2.2 Unpacking and Inspection 2-1

2.2.1 Warranty 2-1

2.3 Installation Procedures 2-1

2.3.1 Cautions 2-1

2.3.2 Cabling and Wiring 2-2

2.3.3 Adjustments and Selections 2-3

2.3.4 Mechanical Mounting 2-4

2.3.5 Post-Installation Checks 2-5

2.3.6 Voltage/Resistance Checks 2-5

2.3.7 Power On Checks 2-5

2.4 Continued Airworthiness 2-5

2.5 Accessories Required But Not Supplied 2-5

2.6 Installation Drawings 2-6

3 Operation

3.1 Introduction 3-1

3.2 General 3-1

3.3 Operation Specifics 3-1

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These commodities, technology or software are controlled in accordance with the United States Export Administration Regulations, Export Classification

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SM270 Rev. 4.10 Model 270 Universal Interface Amplifier Manual

Section 1 Description

1.1 Introduction

This manual contains information on the Model 270 Universal Interface Amplifier. All

derivative products will be covered by manual supplements, which can be obtained from

NAT as required.

Information in this section consists of purpose of equipment, features and specifications.

1.2 Purpose of Equipment

The Model 270 Universal Interface Amplifier is designed to provide multipurpose

amplification and switching functions for varying radio, microphone, and custom audio

interface needs. The unit is designed to interface radios to operator headsets and

microphones and provide specialized switching functions such as voice activated

switching, radio PTT switching, or other interface functions. The Model 270 can be used

as a primary amplifier for an aircraft or vehicle operator station or it can be used as an

auxiliary amplifier for interface or other applications.

1.3 Features

The Model 270 has Audio, MIC, and Spare Input channels. The Audio Input (receiver)

channel is a balanced (differential) type input; the MIC and Spare Input channels are

single-ended (ground referenced) and designed for interface to commercial DC-biased

microphones or similar low-level audio signals from virtually any source.

Signals applied to the Audio Input channel are reproduced at the Audio Output channel,

the MIC Input channel is reproduced at the MIC Output channel, and the Spare Input is

reproduced at the Spare Output channel. Signals applied to the MIC Input channel can

also be routed to the Audio Output channel by adjusting the MIC SDTN level adjustment

trimmer for the desired audio level.

The Model 270 also includes a multipurpose switching relay capable of performing

different functions. Model 270 functions and specifications are outlined in Sections

1.4.1.1 through 1.4.1.4. A discrete input is provided for controlling the relay in a keyed

mode (e.g. ground to activate or PTT), or alternate action (e.g. latched to another

position with each ground applied). VOX controlled mode (e.g. by audio signals applied

to the Spare Input) is also available. The switching relay can be used to control radio

keying, audio switching, interphone mode switching, music muting, or other specialized

functions as needed.

Dec 12, 2006 Page 1-1

ENG-FORM: 800-0108.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

These commodities, technology or software are controlled in accordance with the United States Export Administration Regulations, Export Classification

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Model 270 Universal Interface Amplifier Manual SM270 Rev. 4.10

1.4 Specifications

1.4.1 Electrical Specifications

1.4.1.1 Functions

FUNCTION DESCRIPTION

Audio Input Channel

(receiver audio)

A 600 Ωbalanced audio input that is routed to the Audio Output

channel.

MIC Input Channel A single-ended input (ground referenced) that is routed to the

MIC Output channel and to the Audio Output channel if desired

for MIC Sidetone. A 22 mAdc microphone bias from a 9 Vdc @

400 Ωsource or a 600 Ωground termination resistance are

selectable by mini-switch MS3. MS3 can also be unplugged to

raise the input impedance to >10 KΩ.

This input is suitable for microphone input signals or any other

low level audio signals in a range from 20 mVrms to 1.5 Vrms.

Spare Input

Channel

A single-ended input (ground referenced) that is routed to the

Spare Output channel. A 22 mAdc microphone bias from a 9

Vdc @ 400 Ωsource or a 600 Ωground termination resistance

are selectable by mini-switch MS2. MS2 can also be unplugged

to raise the input impedance to >10 KΩ.

This input is suitable for microphone input signals or any other

low level audio signals in a range from 20 mVrms to 1.5 Vrms.

Audio Output

Channel

(receiver or

headphone audio)

The Audio Output channel is fed by the Audio Input channel.

The amplifier gain for the Audio Output channel is adjustable by

trim potentiometer VR2. MIC Sidetone audio from the MIC

Input channel can also be routed to the Audio Output channel if

VR2 is adjusted for the desired level. Set VR4 fully counter-

clockwise if MIC Sidetone is not desired.

The Audio Output channel can drive loads ranging from 8 Ωto

greater than 600 Ω. Mini-switch MS5 is used to select 8 Ωor 600 Ω

load compatibility. The Audio Output channel is transformer

coupled.

MIC Output

Channel

The MIC Output channel is fed by the MIC Input channel. The

amplifier gain for the MIC Output channel is adjustable by trim

potentiometer VR1. The MIC Output channel can drive loads

ranging from 8 Ωto greater than 600 Ω. Mini-switch MS4 is

used to select 8 Ωor 600 Ωload compatibility. The MIC Output

channel is transformer coupled and also includes a 1µF AC

coupling capacitor. Internal jumperJ1 is installed if direct DC

coupling from the transformer secondary is desired. Remove

J1 if AC coupling is desired. The MIC Output can drive DC-

biased or ground-referenced loads if AC coupled.

Page 1-2 Dec 12, 2006

ENG-FORM: 800-0108.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

These commodities, technology or software are controlled in accordance with the United States Export Administration Regulations, Export Classification

Control Number(ECCN) EAR99. When exporting, diversion contrary to U.S. law is prohibited.