Abstract: A magnetic disk for a hard disk drive comprising a distributed track identifier is described. The disk includes a first portion of a track identifier physically located at a first location on a disk sector and a second portion of the track identifier physically located at a second location on the disk sector wherein the first portion and the second portion of the track identifier are discontinuous on the sector.

Abstract: A system provides for remote monitoring using asynchronous code division multiple access (CDMA) communication techniques between a base station and one or more transponders. Each transponder is attached or otherwise associated with an object or an environment to be monitored. Upon receipt of an interrogation signal, a transponder generates and transmits a coded transponder signal containing the monitored data. The coded transponder signal is generated using a spreading code. Each transponder is associated with a unique, mutually exclusive set of spreading codes. Each spreading code is based on a unique transponder address and the monitored data to be sent. A detector asynchronously monitors received signals for any of the available spreading codes. Once the detector detects a particular spreading code, the base station can identify the source transponder and extract the monitored data.

Abstract: A data recording medium has tracks with pseudo-noise (PN) sequences with good autocorrelation properties as servo information for controlling the position of the recording head. A first set of alternating tracks uses a leading pseudo-random binary sequence (PRBS), which is a PN sequence with good autocorrelation properties, and a following PRBS that is cyclically shifted from the leading PRBS. A second set of alternating tracks interleaved with the first set also has a leading PRBS and a following PRBS that is cyclically shifted from the leading PRBS, but the leading PRBS in each of the tracks in the second set is offset along-the-track from the leading PRBS in the tracks of the first set. The head positioning control system uses the leading PRBS to generate a servo timing mark (STM), the cyclic shift to generate track identification (TID), and the following PRBS from adjacent tracks to generate the head position error signal (PES).

Abstract: A data recording system uses a recording medium in which the tracks have pseudo-noise (PN) sequences with good autocorrelation properties as servo information for controlling the position of the recording head. A first set of alternating tracks uses a leading pseudo-random binary sequence (PRBS), which is a PN sequence with good autocorrelation properties, and a following PRBS that is cyclically shifted from the leading PRBS. A second set of alternating tracks interleaved with the first set also has a leading PRBS and a following PRBS that is cyclically shifted from the leading PRBS, but the leading PRBS in each of the tracks in the second set is offset along-the-track from the leading PRBS in the tracks of the first set. The head positioning control system uses the leading PRBS to generate a servo timing mark (STM), the cyclic shift to generate track identification (TID), and the following PRBS from adjacent tracks to generate the head position error signal (PES).

Abstract: A method for use in connection with any kind of detector that receives an input signal via a partial-response channel and which provides a detector output signal and a merge-bit signal. According to the present scheme, the colored noise of the input signal is whitened in order to provide a filtered signal. The filtered signal is filtered to provide a first output signal using a first matched filter and a second output signal using a second matched filter. The merge-bit signal is used to adjust the first matched filter to match a first most likely error event and to adjust the second matched filter to match a second most likely error event. It is then determined whether said first likely error event or said second likely error event is the most likely error event, and the actual errors of detector output signal are corrected using said most likely error event.