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 AVAD (Automatic Voice Alert Device) is a highly versatile voice alerting system. It stores pre-recorded human speech in digital form and operates under microprocessor control to assemble messages from words and phrases, held in the store. AVAD’s voice is not synthesized and can be in any language, male or female, providing the right degree of stress and urgency for each situation. The quality of speech is so good that the speaker’s voice remains recognisable and highly intelligible even under stressful environmental conditions, such as noisy cockpits and armoured fighting vehicles.
The message priority order, repetition rate and volume are preprogrammed to individual customers’ requirements to give the maximum information to the operator without disrupting performance of his primary task.
AVAD incorporates the benefit of research, conducted by the British Medical Research Council from which psychologically engineered attention tones have been derived and approved by the CAA.
This one compact unit integrates and controls all the voice messages and audio tones required in any complex system. Automatic message priority regrading is available where required recognising the fact that message priorities may vary from situation to situation. The unit may be ‘keyed’ from most types of sensor and will accept a wide range of trigger voltage levels. It also has built-in test and continuous self-monitor facilities for added user confidence.
AVAD can replace all existing discrete audio warnings thus reducing the installation cost and complexity of new projects. It is also simple to retrofit.
Advantages of AVAD
- High Quality human speech
- Faster crew/operator response
- High intelligibility in noise
- Appropriate message emphasis
- Microprocessor control of message format
- Any voice in any language
- Low disruption, noise penetrating attenson tones available
- Message priority sequencing with regrade capability
- Mix of tone and voice outputs
- Continuous self-monitoring
- Simple to re-programme
- Simple, low cost installation
Technical Description
V694
The AVAD V694 is designed to integrate and control audio alerts, be they voice or tone, and is activated by ‘keying’ signals from remote system sensors and/or push buttons. The message format is completely flexible and, for example, in civil aviation circles, AVAD conforms to ARINC 577 ‘Audible Warning System’ and ARINC 726 ‘Flight Warning Computer System’.
Approximately sixt-four seconds of pre-recorded human speech can be digitally encoded and stored as a vocabulary of messages, phrases, words and tones. Messages can be constructed using words and phrases drawn from unit memory under software control, allowing the total duration of all message outputs to exceed the vocabulary capacity by a considerable amount. High quality reproduction is achieved with an advanced digitised speech technique and selective analogue filtering within the unit. Up to 16 message channels offer +ve or OV keying. The unit will respond to single an multiple keys. Four analogue channels can respond to variable d.c. voltage inputs offering a sensitivity of up to 256 logic switching steps across the input range. A stabilised 5 V d.c. output is available for use as a reference for an external potentiometer. Typical variable readouts might be aircraft height, voltages or pressures.
Unit operation and vocabulary store may be defined by the user, (programme software allows control of each message cycle). Each message has Normal, Regrade and Test priority values assigned to it. The output sequence is then controlled by the regrade and test inputs. The audio outpurs are provided: one at telephone/headset level and the other for driving a loudspeaker direct. The nominal level of each output can be set by individual preset potentiometers offering 20dB range with the relative volume of each message or message repeat under the control of operating software. The complete message format, including a repetition rate, pauses, message inhibit/de-inhibit, and tones may be similarly controlled.
A key input is provided which will inhibit any message in progress without affecting other keyed messages. The message thus inhibited would normally remain so until its sensor input is removed and reapplied. Alternatively, the inhibit may be removed after a specified time, if the warning message keyline remains activated during this period.
Full test/reset facilities provide fast checking of unit operation. Correct operation of the microprocessor and amplifier circuitry and control programme status are continuously self-monitored. In the event of a fault condition both audio outputs are automatically inhibited and a ‘fail’ output is provided to activate an indicator to warn of unit failure.
V695
The V695 is a smaller 7 channel unit with microprocessor control offering all the programming flexibility of the V694 and storage capacity of 8 seconds.
V691
The V691 is a single output device ideal for applications where only one warning such as ‘fire’ or ‘pull up’ is required. A second keyline may be used to provide a ‘system enable/disable’ input. The output repeats continuously when keyed.
V696
This unit offers similar facilities to V691 but the message is output once only in response to valid keys.
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