Our Engineers' Patent Portfolio - Digital Signal Processing

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Rate adaptaptive subscriber line ("RADSL") modem and method of operation

Patent Number 5,805,669

Existing customer premises wiring can be used with high speed digital modems, such as RADSL modems by using POTS filters in line with each piece of PSTN equipment. Alternatively, an RADSL modem includes a line monitor which detects when a piece of PSTN equipment experiences a hook-switch transition. Upon that occurrence, the error detection circuitry in the RADSL modem is disabled for a time period sufficient to avoid the counting (with associated RADSL modem rate change) of any burst errors associated with the PSTN equipment going off-hook or on-hook.

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Method and apparatus for automatically adjusting the transmit power of data communication equipment operating in a multipoint environment

Patent Number 6,549,568

A method and apparatus for automatically adjusting the transmit power level of a data communication equipment (DCE) device being used in an environment in which one or more telephones and one or more DCEs may be connected to the same twisted wire pair. When a telephone goes off-hook, the receiver of the DCE notifies the processor of the DCE that the telephone has gone off-hook. The receiver comprises an equalizer which generates a tap signature based on the off-hook condition of the telephone and deliver the tap signature to the processor. The processor compares the tap signature with tap signatures stored in a memory device until a match has occurred. The processor then reads the transmit power level associated with the matching tap signature out of the memory device and sets the transmit power level of the transmitter of the DCE to the transmit power level read out of the memory device.

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