Lsi Logic Corporation

Paul C Gregory

Andrew Popplewell

An on-chip data independent method and apparatus for channel error estimation in a data recovery scheme is based on measuring phase noise statistics. The apparatus () receives a data pulse and four quadrature clock signals and has a discriminating device () to provide a count signal for each data pulse received depending on which clock signal was the first to clock the particular data pulse. A pair of counters (and) counts the number of data pulses received at different phase offsets to provide a value representing a statistical ratio of the counts at different clock phase offsets from which an error rate for the received data pulses based on the counts at different clock phase offsets can be determined from a look-up table (). By re-configuring the circuitry, the system can be adapted to measure clock window asymmetry.

Method and apparatus for estimation of error in data recovery schemes

In a frequency control arrangement,of the type comprising an oscillator,a mark or space counter,a frequency detector,and an error signal calculator,and in which it is desired to control the oscillator,to resonate at a frequency substantially equal to the frequency of a received data stream, the oscillator,is implemented as a four phase ring oscillator (FIG.,ref,) arranged to provide phased clock signals to the mark or space counter (FIG.,ref,). This allows the mark or space counter to be arranged to measure the length of the marks or spaces of the data with increased resolution.

Growing community of inventors

Bolton, United Kingdom

Paul C Gregory