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MOTOROLA Technical Developments
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ENHANCED VOICE-OPERATED TRANSMllTER
by Klaus Dirksmeier and Reiner Bingel
ABSTRACT
The transmitter of a communication unit is designed to operate when it both receives voice modulation and a further condition is fulfilled. That further condition can be that one or more of several different criteria are met, such as that the presence of a human face has been sensed by its temperature and/or distance.
Operator voice + additional control condition = trigger for transmitter
INTRODUCTION
The idea provides a sophisticated triggering of transmitter operation for a communication system. At least an operator's voice and one other condition must be fulfilled before the transmitter operates. The communication unit may be a portable or mobile radio.
PROBLEM TO BE SOLVED
If transmission by a communication unit is trig- gered by voice operation alone, termed VOX opera- tion, this can lead to faulty operation in a noisy environment.
The noise tends to trigger the transmitter ran- domly.
PROPOSED SOLUTION TO THE PROBLEM
The proposed solution to this problem lies in adding an additional control criterion, besides just the presence of a voice, to trigger the transmitter.
Possible control criteria could be eg. infrared, ultrasound, movement, emission or absorption mea- surement. The communication unit is provided with a sensor which detects one or more of these. The control threshold which is set corresponds to reason- able likelihood that a desire...