Pseudo-full duplex televisiontelephone loudspeake
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专利名称：Pseudo-full duplex television/telephone loudspeaker system
发明人：Peter C. Skerlos,Thomas J. Zato
申请号：US06/304226
申请日：19810921
公开号：US04414432A
公开日：
19831108
专利内容由知识产权出版社提供
摘要：A television/telephone loudspeaker system is disclosed wherein feedback oscillation caused by having a speaker phone system simultaneously in the transmit and receive mode is minimized. Improved separation of transmit and receive signals is accomplished by microprocessor-controlled dynamic balancing of a bridge network coupled to a telephone isolation transformer to which the incoming and outgoing calls are provided. In addition, by microprocessor sampling of the television receiver's loudspeaker drive voltage from the telephone input line, dynamic proportional attenuation of microphone gain (AGC) is digitally accomplished in simulating full duplex operation. Bridge balancing is accomplished by means of test signals output by the microprocessor during quiet periods with various other audio signal refinements, such as room background noise cancellation, available with the constant monitoring of the microphone signal. Audio and visual indications of an incoming telephone call are provided by the television receiver's tuning system microcomputer which detects and decodes user remote commands and activates a phone relay and phone light emitting diode (LED) drivers.
申请人：ZENITH RADIO CORPORATION
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