Patent ID: 6877116
Filing Date: 2005-04-05
Classification: G11B

Abstract:
1. A method of determining bit error rate in a sampled data system having a disc formed of a magnetic recording medium and a data head for writing data on the disc and retrieving data from the disc, the method comprising steps of: (a) writing a pattern on the disc, the pattern including isolated instances associated with a predetermined error event; (b) retrieving the pattern from the disc; (c) averaging the isolated instances to obtain a representative instance having a reduced media noise component; (d) determining a difference between the representative instance and each of the isolated instances to obtain a corresponding number of noise sequences; (e) averaging the noise sequences over the isolated instances to obtain an autocorrelation component based on the isolated instances read from the disc and the noise sequences; (f) deriving a channel filter having an impulse response based on the representative instance and based on imposed channel requirements for a predetermined channel model and deriving an autocorrelation matrix at an output of the channel filter based on the impulse response; (g) passing the representative instance through the filter with the impulse response to obtain a filter output sample; and (h) determining an error value indicative of the bit error rate based on the filter output sample and the autocorrelation component.