A system for DC restoration of serially transmitte

专利名称：A system for DC restoration of serially

transmitted binary signals

发明人：Webster, Stephen申请号：EP94300490.3申请日：19940121公开号：EP0611059A2公开日：19940817

专利附图：

摘要：A DC restorer device for restoring the DC and non-zero average components ofa serially transmitted binary signal which has been AC coupled. The device comprises aninput port for receiving the binary signal, a clamping circuit, a feedback network, a

summing node, and an output port. The input port is connected to a capacitor for ACcoupling the binary signal to the summing node. The clamping circuit is also connected tothe summing node. The feedback network includes an input and an output which are alsoconnected to the summing node. The clamping circuit clamps the positive and negativepeaks of the AC coupled binary signal which exceed a predetermined range. The

feedback network latches the AC coupled binary signal and produces a feedback current.For a binary signal which is within the predetermined range, the clamping circuit exhibits avery high input impedance, thereby causing the feedback current to charge the couplingcapacitor. The coupling capacitor produces a voltage which is added to the AC coupledbinary signal at the summing node. The output port which is part of the feedbacknetwork takes the restored AC coupled binary signal and converts it to digital logiclevels using a comparator. In another embodiment, the clamping circuit includes a currentsensor for producing an amplitude signal which is indicative of the amplitude of the ACcoupled binary signal. The amplitude signal is fed to an automatic gain controller whichproduces a gain control voltage for controlling the operation of a high frequencyequalizer. The second embodiment of the present invention provides a DC restorer whichcan be merged with an automatic gain controller to provide an integrated cable equalizerin which the DC restorer and high frequency equalizer co-operate to produce a matchedand high performance cable equalizer.

申请人：GENNUM CORPORATION

地址：P.O. Box 489, Station A Burlington, Ontario L7R 3Y3 CA

国籍：CA

代理机构：Knott, Stephen Gilbert

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