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
Vector smoothing of complex-valued cross spectra to estimate power spectral density of a noise signal
Method and system for providing autonomous retransmissions in a wireless communication system
Synchronizing presentations of multimedia programs
Nucleobindin I variant protein compositions and methods of use
.gamma.-L-PGA producing microorganism, method of producing .gamma.-L-PGA using the microorganism, crosslinked substance produced using the microorganism, and external dermal agent produced usi
Framework for open dynamic reflective applications
Plated photopolymer based fuel cell
  Randomly Featured Patents
Steam expandable polymeric composition and method
Automatic bread making machine
Structure of inflatable tubes with closed loop connectors
Sputtering apparatus for coating elongated tubes and strips
Solid-state high-power oscillators
Method and apparatus for reducing drop placement error in printers
Frequency measuring system
Optical switching apparatus
Switched-mode power supply