Multipoint data modem communication system
Patent 4817114 Issued on March 28, 1989. Estimated Expiration Date: 
March 2, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 2, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesTiming acquisition in voiceband data sets Digital data receiver including timing adjustment circuit Patent #: 4577334 InventorsAssigneeApplicationNo. 07/163357 filed on 03/02/1988US Classes:375/222, Modems (data sets)375/231, Training period or initial set up375/232, Adaptive375/377MISCELLANEOUSExaminersPrimary: Griffin, Robert L.Assistant: Huseman, Marianne Attorney, Agent or FirmInternational ClassH04L 25/03 (20060101)Foreign Application Priority Data1987-11-16 GBAbstractA multipoint data modem communication system includes a control modem (12) and a plurality of tributary modems (14, 16, 18). During an initial training mode, receiver parameters and equalizer coefficients are determined and stored in a storage device (156) in the control modem receiver at addresses associated with the tributary modems. During subsequent relatively short training signals, the stored parameters are accessed. The remote modems transmit identification address tones in parallel with the subsequent training signals, at frequencies separated by 200 Hz intervals from the training signal spectrum frequencies. A plurality of Discrete Fourier Transform (DFT) filter circuits (190) are utilized to determine the transmitted addresses by measuring the correlation of the received signal with locally-generated frequencies. | |
