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
System and method for detecting executable machine instructions in a data stream
Integrated advance copper fuse combined with ESD/over-voltage/reverse polarity protection
Flexure with insulating layer isolating a portion of a metal substrate
Probiotic enriched and low organic acid food products
Touchscreen with Z-velocity enhancement
Cable exit trough with insert
Transferring a document
  Randomly Featured Patents
Testis-specific cystatin-like protein cystatin T
Winged practice ball
Method and apparatus for electrically interconnecting signalling lamps and sockets
Pivotal gutter bracket
Contact-type imager for scanning moving image-bearing members
Linear lost motion positioning mechanism
Internal-wall drain system
System and method for caching called number information
Fluorescent water-soluble polymers