US 2006/0188040 A1 · Data channel with sampling rate less than the channel bit rate

Abstract

Due to code constraints and pickup limitations of optical pickups, much of the signal energy of a binary coded analog signal, and therefore much of the information content, has dissipated at frequencies above about one-half (or even above about one-fourth) of the sampling frequency fs. For example, the response of data streams from DVD layers falls off by about 40 dB by fs/4 while the response of a CD data stream falls off by about 18 dB by fs/4. Thus, a data channel is provided in which the sampling rate fs is less than the channel bit rate fb. The data channel may be part of an optical storage drive in which data has been RLL encoded at d≧0 and the sampling rate may be one-half the channel bit rate. Preferably, a sequence detector is employed which outputs two channel bits for each input sample.

Claims32

Dependent claims

A data channel, comprising:

a receiver for processing a binary coded signal having potential transitions occurring at a first frequency f1 and actual successive coded transitions being separated by at least one potential transition;
and
a detector for processing the digital samples at a second frequency f2 less than the first frequency f1 and generating channel bits at the first frequency f1.

Dependencies are inferred from the claim text.

Data channel with sampling rate less than the channel bit rate

Life of this patent

Data channel with sampling rate less than the channel bit rate

Life of this patent

Abstract

Claims32