Telecommunications – Receiver or analog modulated signal frequency converter – Signal selection based on frequency
Patent
1978-03-16
1980-10-21
Griffin, Robert L.
Telecommunications
Receiver or analog modulated signal frequency converter
Signal selection based on frequency
35 35C, 179156R, 179167, 320 2, H04B 900
Patent
active
042298296
ABSTRACT:
Apparatus for wireless transmission of a teaching program in a classroom comprises a transmitting unit comprising a casing which houses one or more tape recorders with operating elements, a microphone and a plurality of infrared transmitters. A removable cover which can be hung on the wall has additional infrared transmitters connected by a cable to the transmitting unit. Each student has a head set with an infrared receiver, earphones and a microphone. The transmitting unit is remotely controlled by a portable ultrasonic transmitter. When not in use, the headsets are placed in a cabinet where the batteries of the headset are charged by means of induction coils on the head sets being magnetically coupled with induction coils in the cabinet to which high frequency current is supplied. The students may also have cassette recorders which, when not in use, are placed in charging chambers where power is transmitted from primary windings in the chambers to secondary windings in the cassette recorders to charge the batteries of the recorders.
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Sennheiser Infra-Red Headphones-Electronics Australia-Apr. 1976, vol. 38-#1-p. 25.
Conrad-Headphones, Infra-Red Stereo and Microphones-Funkschau, vol. 48, #24, pp. 1061-1062, Nov. 19, 1976.
Free-Cordless Headphones-Popular Science-Jan. 1976, p. 91.
Adams Bruce L.
Burns Robert E.
Griffin Robert L.
Lobato Emmanuel J.
Orsino Jr. Joseph A.
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