Resources Contact Us Home
Method and apparatus for DC restoration in digital receivers

Image Number 5 for United States Patent #4873702.

A technique for eliminating unwanted dc offset voltages in a receiver for decoding a plurality of multilevel digitally modulated signals. The data transmission system is arranged to send a particular preamble signal each time a different data source begins transmission of its data. The preamble signal produces at the receiver output multiple cycles of maximum level excursions. During the period of time that the preamble signal is received, a signal processor in the receiver determines an initial dc offset value by averaging the level of the received digitally modulated signal. After the transmission of the preamble, the signal processor continually generates updated dc offset voltages which are equal to the sum of the previously generated dc offset voltage and the difference between the amplitude level represented by the received digitally modulated signal and the amplitude level of the closest "coding" amplitude level; the difference being multiplied by a scaling factor. Once a scaling factor is applied to the updated dc offset value, the result is added to the previous dc offset voltage. And, the process is continually repeated to produce updated dc offset voltages.

  Recently Added Patents
Pharmaceutical and diagnostic compositions for use in the treatment and diagnosis of neurodegenerative diseases or amyloid diseases
Heat shield and laminated glass
Thermally efficient busway
Identifying users of remote sessions
Toner cartridge
Fabrication method of packaging substrate having through-holed interposer embedded therein
Stroboscopic light source for a transmitter of a large scale metrology system
  Randomly Featured Patents
Interface for logic simulation using parallel bus for concurrent transfers and having FIFO buffers for sending data to receiving units when ready
Gallium nitride-based compound semiconductor light emitting device
Process for producing polyurethane
Process and reagent for the determination of prothrombin
Semiconductor chip and multi-chip module
Pistonic motion, large excursion passive radiator
Reverse wound electrodes
Imide derivatives and compositions for use as antipsychotic agents
Electronic device with EMI shield spring device
Chrysanthemum plant named `Yoroxanne`