Northern Airborne Technology MB01 - Manual (Page 4)

MB01-001Matching Box
SM72 Installation and Operation Manual
Section 1 Rev: 1.00 Issue 4 Page 1-1
ENG-FORM: 800-0114.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Section 1 Description
1.1 Introduction
Information in this section consists of product description, design features and specifications for the
MB01-001Matching Box. All derivative product information shall be contained in the applicable manual
supplement, which may be obtained from NAT as required.
Review all notes, warnings and cautions.
1.2 Product Description
The MB01-001 is a remote mounted audio level matching unit for 8 transceivers and 10 receivers. It
provides 8 floating key signals and is capable of providing unamplified artificial sidetone. The unit also
provides a diode OR’ed DF Mute signal when any of the transceivers are keyed.
1.3 Design Features
The MB01-001 is made up of 8 subassemblies: 2 ‘Receiver’ subassemblies, 4 ‘Transceiver’
subassemblies, one Test subassembly and one Backplane subassembly. Each ‘Receiver’ subassembly
supports 5 receivers and each ‘Transceiver’ subassembly supports two transceivers. The Test
subassembly connector provides the installing agency access to all microphone and receive signals while
all the equipment is connected. This allows proper level adjustments to be made while all inputs and
outputs are loaded. The MB01-001 supports real sidetone, dedicated sidetone inputs (with 6dB of
attenuation) and can generate unamplified artificial sidetone. All connectors are labeled to assist with
proper connection to the airframe wiring.
1.4 Specifications
1.4.1 Electrical Specifications
Input Signals
Quantity 18 Receive inputs
8 Microphone inputs
8 Sidetone inputs
Audio Level 4.9 Vrms nominal for receive inputs
4.9 Vrms nominal for sidetone inputs
1 Vrms nominal for microphone inputs
Impedance 350
Ω ±10% max for microphone inputs
600
Ω ±10% for receive inputs
1000
Ω ±10% for sidetone inputs
Circuitry Type All are balanced inputs
Keylines PTT <30 mA input current