aerovalley technologies acp100-300-2 audio control panel · the pre-amplifier also contains a noise...

Aerovalley Technologies

ACP100-300-2

AUDIO CONTROL PANEL

INSTALLATION MANUAL

Revision 01

June 2013

Aerovalley Technologies

Lot 100 Green Valley Road Telephone: (08) 8390 1222

Norton Summit Facsimile: (08) 8390 1322 South Australia Email: [email protected] AUSTRALIA 5136 Web: www.aerovalleytechnologies.com

http://www.aerovalleytechnologies.com/

ACP100-300-2 Audio Control Panel Installation Manual Revision 01

Copyright 2013© Aerovalley Technologies 2

Table of Contents

Section 1 Description and Specifications 1.1 Purpose of Equipment 1.2 Features 1.3 Physical Specifications 1.4 Environmental Specifications 1.5 Electrical Specifications 1.6 Interface Specifications

Section 2 Installation 2.1 Equipment required but not supplied 2.2 Installation Considerations 2.2.1 Cooling 2.2.2 Equipment Location 2.2.3 Routing of Cables 2.2.4 Cable and Wiring 2.2.5 Interconnection

Section 3 Installation Procedure 3.1 Audio/Mic Level Adjustments 3.2 Outline Drawings 3.3 Interconnect Drawing

Section 4 Post Installation Checks Section 5 Certification Basis



Section 1 - Description and Specifications

1.1 Purpose of Equipment The ACP100-300 Audio Control Panel is specifically designed to allow the integration of commercial and aircraft radio equipment into one aircraft audio system, using no external interfacing units. The ACP100-300 has daul microphone inputs with adjustable gain, bias, relay keying and sidetone generation. It also provides six transceiver adjustable microphone and audio outputs, all transformer isolated. Two switched and one unswitched audio inputs. The ACP microphone amplifier is centred around an Analog Devices microphone pre-amplifier chip, which has variable compression and noise gating circuitry. This allows signals to be amplified for optimum signal levels for further mixing and buffering, to intercom and various radio systems that may be installed. The frequency response has been tailored to help reduce the noise characteristics found in high noise turbine aircraft. Transformer isolation of the aircraft microphone (typically a noise cancelling electret) allows complete isolation of DC and longitudinal noise induced on the headset leads caused by direct radiation and ground loop interference induced into the airframe (by alternators and other electrical equipment). This also provides the biasing voltage and correct impedance matching to be presented to the head set microphone unit. In operation the unit provides about 6 – 10dB of improvement in the signal to noise quality of the pilots speech over the original unit, improving the intelligibility of air to ground communication significantly, and also helps prevent the overdriving of the radios fitted to the aircraft which causes distortion and RF splatter. The pre-amplifier also contains a noise gate to mute the audio when microphone levels fall below a predetermined point, allowing for noise to be reduced in multiple pilot systems with intercom facilities. In the current model APC-1 there is provision for a second microphone input with FET muting of the second microphone channel, to a buffer amplifier which feeds 6 output stages and an internal intercom buss system. There is also ‘fail safe’ bypass switching fitted in case of system failure allowing direct headset access to the prime radio unit in position 1. Each of the 6 output stages has its own adjustable output level and transformer system to supply the correct isolated audio level to the radios in the aircraft at the correct impedance of 150 ohms, allowing a wide variety of units to be used, from standard VHF air radios through to CB UHF style units. Features All transceiver inputs and outputs are transformer isolated – minimises earth loop induced noise. All have a 2kV

breakdown voltage. Operated on 28VDC electrical system. Dual microphone inputs with keying relay contacts, (NO.), provide for every transceiver, PTT. and Microphone Priority keying and ICS to primary microphone. Two switched Nav inputs and a third unswitched audio input user selectable. Accommodates a wide range of radio microphone output levels and impedances, 15mVPP – 2.5VPP 1 x 50ohm outputs up to 0dbm is provided, (3x 150ohm Headsets) Input microphone gain adjustable Basic parameters are as per below

~ 10dB / Octave below 200Hz.

6dB / Octave 200 – 300Hz.

12dB / Octave above 2200Hz.

Compression Ratio ~ 10dB.

Compression release time ~ 100mS



Roll over to Mute point – 58dBm.

0.2% typical distortion.

Complete isolation of microphones from pre-amp circuits for DC and longitudinal noise.

Provision for 2 isolated microphone channels.

Input & Output Z = 150 ohms.

6 individual isolated outputs for radio interfacing.

Variable output level on each output for optimum radio performance.

ICS with adjustable levels.

System operating voltage 24-28 volts. Notes: Noise or poor audio quality in the transmit signal of a commercial radio operating in an aircraft is generally due to three main sources:

1. Noise picked up by the microphone – can only be controlled by the quality of the noise cancelling microphone and careful setting of the microphone gain.

2. Ground/earth loop problems in the circuit between the microphone and the radio – when wired correctly the mike input circuitry of the ACP100-300 is specifically designed to minimise these problems.

3. Incorrect impedance matching and overdriving the microphone input circuit of the radio – the interface adaptor output should preferably match the AC and DC impedance and output level of the microphone originally fitted to the radio.

1.3 Physical Specifications Height: 47.6 mm (1.87 inches) Depth: 142.5 mm (5.61 inches) Behind panel Width: 146 mm (5.75 inches) Weight: 500 g (1.0 lb) Mounting: Dzus mount 1.4 Environmental Specifications Temperature: -40 to +50 Degrees C (operating) Altitude: 15,000 ft max. Humidity: 95% non-condensing 1.5 Electrical Specifications Voltage: +28VDC (Pin selectable). Current: Max. 250mA with full bright lights.



1.6 Interface Specifications

Audio Output:

Level: 10.5VPP into 50.

Impedance: >50. Microphone Output: Level: +8dbm (adjustable).

Impedance: 150 nominal Frequency Range: 300Hz to 3.5kHz, -6db points.

Section 2 – Installation 2.1 Equipment Required: The following equipment is required, but not supplied with the ACP100-300 Audio Control Panel. Qty 1 Connector DB25S Qty 1 Connector DB15S Qty 1 Connector DB9S Qty 50 Socket contact Qty 1 Connector Hood DB25 Qty 1 Connector Hood DB15 Qty 1 Connector Hood DB9 2.2 Installation Considerations 2.2.1 Cooling No direct cooling is required. As with any electronic equipment, overall reliability may be increased if the ACP100-300 is installed away from any high heat sources. 2.2.2 Equipment Location The ACP100-300 must be mounted within the pressurised region of the aircraft. Consideration should be given to areas with minimal temperature fluctuations. The ACP100-300 should not be installed near devices, such as inverters, which produce strong AC magnetic fields. 2.2.3 Routing of Cables Care must be taken not to bundle the wiring from the ACP100-300 with any wires containing high-energy or sources of electrical noise such as transmitter coax lines, AC power wiring and electric motors. Care must be taken to tie wiring harness clear of aircraft controls and cables 2.2.4 Cable and Wiring All audio wiring should be at least 24 AWG and power and ground wiring should be at least 22 AWG. The use of Tefzel M27500 (for shielded wiring) and Tefzel M22759/16 (for non-shielded wiring) is recommended, or as specified by OEM or design authority of the installation. 2.2.5 Interconnection It is important that the Chassis Ground be grounded to minimise radiated interference. The Chassis ground must be grounded as near as possible to the ACP.



Section 3 – Installation Procedures

3.1 ACP100-300 Audio/Mic Level Adjustments



3.2 ACP100-300 Outline Drawing



3.3 Interconnect Drawing



Note: The installer must establish compliance with the design rule specified in the certification basis of the aircraft and Civil Aviation Order Section 108.34 or the installation requirements pertaining to the regulatory authority for the country of registration, for the aircraft

Section 4 – Post Installation Checks Prior to connecting the ACP100-300 unit to the mating connector, ensure that there is power on either pin12, and ground on Pin 4 on the D15 aircraft connector. Ensure that there is continuity of less than 0.5 ohms between pin 14 and airframe ground. Operate the Radio Transceivers interfaced to the ACP100-300 and adjust Sidetone, Audio RX level and Microphone gain, as required to ensure satisfactory operation of the Radio Transceiver. After satisfactory operation place the lid cover.

Section 5 - Certification Basis Must be installed and certified in accordance with local regulatory requirements

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