Analog Maximum Likelihood Detection for the Magnetic Recording Channel
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
This invention relates to an analog detector in which sample and hold circuits usually associated therewith are avoided by circulating a time-varying waveform in a tapped delay line and sampling over the waveform as a whole (i.e., in parallel). In a maximum likelihood detection of pseudo-ternary transition-encoded waveforms, it has been observed that a sample corresponds to a data ONE if and only if (1) the sample is confirmed as a ONE by a subsequent sample having an adequate amplitude difference, and (2) none of the intervening samples between the sample in question and the confirming sample represent a more likely ONE than the sample in question. To formalize this description, let the amplitude of the kth sample be S(k) and the nominal sample amplitude be A.