The transmitter used pulse-modulated waves at extremely low average power levels. The transmission was immediate. The system was wireless and receiverless, and the sounds were even heard by the deaf. Then in the mid 1970s, Dr. Sharp helped to develop microwave hearing technology for DARPA by conducting research at the Walter Reed Army Institute of Research (WRAIR). In 1973 Dr. Sharp proved that the correct modulation of microwave energy could result in the wireless and receiverless transmission of audible speech.
In 1976 it was reported by the Los Angeles Herald-Examiner that the Soviets were also conducting extensive research into microwave hearing that was brought to the attention of the US Defense Intelligence Agency. Words which appeared to be originating within a person’s skull, they reported, could be induced by microwaves. The technology was to be used for antipersonnel purposes.
The October 1998 US Patent 4877027—Hearing System, mentioned that sound could be induced in the head of an individual using microwaves in the range of about 100 MHz to 10 GHz. The waves consist of frequency modulated bursts lasting from about 500 nanoseconds to 100 microseconds that create a sense of hearing in the individual whose head is targeted. It is effective regardless of a person’s hearing ability.
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