METHOD AND APPARATUS FOR IMPROVING CLASSROOM AMPLIFICATION SYSTEMS AND OTHER RF-TYPE AMPLIFICATION SYSTEMS

摘要

An RF-type amplification system, such as a classroom amplification system,employs technology adapted from a cordless telephonesystem to overcome interference. The amplification system includes a portableremote unit (87) and a base unit (82). Remote unit (87)includes: a microphone (151) for detecting a voice and generatingcorresponding voice signals; a transmitter (160, 161) which generatesRF signals containing the voice signals as well as control signals provided bythe central processing unit (179) of remote unit (87), andan antenna (168) for transmitting the RF signals and for receiving RF signalsfrom base unit (82). Base unit (82) includes an antenna(107) which receives the RF signals transmitted by the remote unit and areceiver (108, 114, 115, 117) which detects the RF signals andseparates the RF signals into the voice signals and control signals. Thecontrol signals are identified by a code detector (118) of base unit(82) and evaluated by a CPU (130). If the values of the control signals are asexpected, the voice signals are processed through a speechnetwork (121) and provided at a communications interface to an audio poweramplifier (147) which amplifies the voice signals and suppliesthe voice signals to speakers which audibly project the voice signals assound. Base unit (82) further includes a transmitter (133, 135) forgenerating RF signals containing control signals but no voice signals, thatare transmitted to remote unit (87), thereby effecting one-waytransmission of voice signals and two-way transmission of control signalsbetween remote unit (87) and base unit (82).