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
Methods and apparatus to determine impressions using distributed demographic information
Hedge shear
System and method for stranded file opens during disk compression utility requests
Register files for a digital signal processor operating in an interleaved multi-threaded environment
Method and apparatus for diagnosing faults in a hybrid internet protocol network
Semiconductor device and method of manufacturing the same
Electronic flash device
  Randomly Featured Patents
Work machine
Encryption processing apparatus, encryption processing method, and computer program
Method for manufacturing semiconductor device
Circuits and methods for sampling and holding differential input signals
Oral composition with an improved teeth whitening effect
Toy riding vehicle
Thermal energy storage composition comprising sodium sulfate decahydrate; sodium carbonate decahydrate; and sodium tetraborate decahydrate
Lightweight concrete
Injectable cross-linked hydrogels for biomaterial applications
Thianthrenium salt cationic photoinitiators