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公开(公告)号：US3921138A
公开(公告)日：1975-11-18
申请号：US52357674
申请日：1974-11-14
Applicant: BELL TELEPHONE LABOR INC
Inventor： BURNS GARY JOSEPH , MOHLENHOFF EDWARD ARTHUR , PASTERNACK GERALD PHILIP , STRONG GARY WAYNE
Abstract: In a multipoint data communications system a multipoint switch responds to polling signals on a signaling path from a central station by extending the signaling path to a selected one of a plurality of remote terminals. Thereafter the multipoint switch blinds itself to signals on the signaling path and remains blinded until there is an absence of signals on the signaling path for a predetermined interval of time. Communications apparatus at the selected remote terminal is enabled by a single frequency tone followed by a silent interval with the single frequency tone and the silent interval being common for all remote terminals.
Abstract translation: 在多点数据通信系统中，多点交换机通过将信令路径扩展到多个远程终端中选定的一个远程终端来响应来自中心站的信令路径上的轮询信号。 此后，多点交换机本身对信令路径上的信号进行盲目，并保持盲目直到信令路径上没有信号达预定的时间间隔。 所选择的远程终端的通信装置由单个频率音调启动，随后是具有单个频率音调的静音间隔，并且所述无线间隔对所有远程终端是公共的。
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公开(公告)号：US3636454A
公开(公告)日：1972-01-18
申请号：US3636454D
申请日：1970-07-28
Applicant: BELL TELEPHONE LABOR INC
Inventor： PASTERNACK GERALD PHILIP , SALTZBERG BURTON R
CPC classification number: H04L27/14
Abstract: FSK data signals are applied to a phase-locked loop whose binary signal output has an average amplitude which varies with the frequency of the incoming data signal. A zero-crossing detector produces a pulse for each zero crossing of the binary signal and the pulses are processed by a transversal digital filter having finite memory and arranged to provide triangular weighting to each input pulse. The baseband signal is then recovered from the filter output. In one embodiment, the zero-crossing detector and the transversal filter are advantageously arranged to be time shared by a plurality of FSK signal channels.
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