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
Method for determining a corrected variance representative of the condition of reception of signals representative of symbols
Strap-hook ring
Lighting fixture
Tandem electric machine arrangement
Workflow optimization for high throughput imaging environments
System and method for providing definitions
Avalanche photodiodes having accurate and reproductible amplification layer
  Randomly Featured Patents
1-aryl- or 1-alkylsulfonyl-heterocyclylbenzazoles as 5-hydroxytryptamine-6 ligands
Antiarrhythmic and tranquilizer composition and treatment
Spring type projecting device
Electric power steering apparatus having a phase compensation section
Manufacture of 4,4'-diisopropylbiphenyl
Motor-driven film transporting device in a single lens reflex camera including means for selectively driving film in a wind-up mode and a rewind mode
Flash memory structure and manufacturing method thereof
Case for a mobile telephone or portable digital media player case having interchangeable panels
Method for producing a reinforced polyester non-woven material
Apparatus for correlating multi-frequency signals