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The error-pattern correction code is a code specialized to correct dominant error patterns observed at the channel detector output in heavy intersymbol interference channels. In this paper, we consider a turbo-equalizer system that utilizes the error-pattern correcting code (EPCC) as a building component. A soft-input soft-output (SISO) decoder for the EPCC is described, and the performance of the proposed turbo equalizer is compared with those of the conventional turbo equalizer and a low density parity check (LDPC) code system. Index Terms--Error pattern correction code, list decoding, turbo equalization.

A new class of high-rate error-pattern-correcting cyclic codes that correct most single occurrences of target error patterns and a significant portion of their multiple occurrences is proposed. This code is based on first designing a generator polynomial of the lowest possible degree that is tailored to any single occurrence of target error patterns. The generator polynomial is then multiplied by a primitive polynomial so that a cyclic code based on a higher degree generator polynomial can handle all single occurrences of the target error patterns, as well as some highly probable multiple occurrences, using the captured syndrome and reliability measure A performance comparison is provided for a jitter-dominant perpendicular recording channel. Index Terms--Cyclic codes, dominant error patterns, generator polynomial, syndrome sets.

We propose a high-rate error-pattern-correcting code constructed by a generator polynomial targeting a set of known dominant error patterns. This code is based on first constructing a low-rate cyclic code that possesses a distinct syndrome set for each target error pattern. This base code is then extended by simply applying the same generator polynomial to a larger message block. It is shown that the captured syndrome along with a soft metric can be used to correct a single occurrence of any target error pattern within the codeword with high probability. The proposed scheme outperforms, by a significant margin, conventional post-Viterbi error correction based on high-rate error-detection coding. The performance comparison is provided for a high-density perpendicular recording model. Index Terms--Biased soft metric, dominant error patterns, generator polynomial, high-rate error-pattern-correcting cyclic code (CC).

We present a particular generator polynomial for a cyclic redundancy check (CRC) code that can be used to detect all dominant error events in perpendicular recording over a broad range of densities. This polynomial is also effective in detecting error events that occur at codeword boundaries. The bit-error-rate and the sector-error-rate performances are validated that result from the use of the corresponding CRC code in conjunction with the well-known post-Viterbi error correction method. Index Terms--Cyclic redundancy check code, dominant error events, perpendicular magnetic recording, post-Viterbi processor.

A strategy for imposing a k constraint without any rate penalty is proposed for recording systems that already employ a post-Viterbi error-correction processor. Although the method is general, we focus on the application to perpendicular magnetic recording. This scheme is based on deliberate insertion of a short pattern, which contains one or more transitions and can be detected by an inner error-detection code, in the prolonged absence of magnetic transitions in the data bit pattern. The post-Viterbi processor attempts an error event correction by examining the likelihoods of a list of error events including the one due to the inserted pattern that forces the k constraint. The signal-to-noise ratio loss compared to the ideal system with k = [infinity] but perfect timing recovery is negligible at either a fixed bit-error rate or a fixed sector-error rate. Index Terms--Cyclic redundancy check code, k constraint, perpendicular magnetic recording, post-Viterbi processor.

We demonstrated the size reduction of axial-mode helical antenna based on Co2Z hexaferrite-glass composite. Axial-mode helical antenna was employed to provide reliable communication for unmanned aerial vehicle (UAV) applications. The conventional axial-mode helical antenna uses an air core or low dielectric material, resulting in large antenna size. To increase the miniaturization factor n=(\mur\varepsilonr)^0.5, a Co2Z hexaferrite-glass composite was used as an antenna core. The 3-dimensional finite element method (FEM) simulation was performed to design a hexaferrite helical antenna and confirm the axial-mode operation at 2.44 GHz with gain of 2.0 dBi. The designed hexaferrite helical antenna showed 82% of volume reduction and good impedance matching compared to the air-core antenna. The axial-mode hexaferrite antenna was fabricated based on the designed structure and characterized in an anechoic chamber. The maximum gain of 0.541 dBi was measured with the pitch angle of 10^\circ at 2.39 GHz. Also, a two-element axial-mode antenna array was designed based on the miniature hexaferrite antenna to further improve antenna gain. Maximum gain of 4.5 dBi at 2.43 GHz was simulated for the antenna array. Therefore, high gain and miniature antenna can be achieved with the combination of Co2Z hexaferrite-glass composite and antenna design technology. [ABSTRACT FROM AUTHOR]

We report a systematic study of the switching behavior and writeability characteristics of perpendicular magnetic recording media in which the anisotropy (Ku) of granular oxides, magnetic volume (M5 · t, product of magnetization and thickness) of cap layer, and exchange coupling between granular oxide and cap layer were varied. The media switching behavior highly depends on the M5t of cap layer as well as the oxide-to-cap exchange coupling strength but little on the Ku of granular oxides. The media switching field Ho at 1-ns scales is strongly affected by switching mode and is greatly reduced with incoherent switching mode. At constant switching mode with fixed M5t of cap layer, the media writeability is primarily determined by the oxide Ku value that affects the Ho. However, when the switching mode varies with different cap M5t or oxide-to-cap exchange coupling strength, no correlation between Ho and writeability is observed. Higher Ku oxide media with higher M5t of cap layer exhibits lower Ho due to more incoherent switching but substantially lower overwrite (OW) than the lower Ku oxide media with lower M5t of cap. Similarly, media with weaker exchange-coupling between oxide and cap layers shows more incoherent switching mode and worse writeability even with lower Ho. Our results have shown that oxide-to-cap exchange coupling as well as oxide Ku is critical in media design for good writeability at high recording density and can be optimized through selection of appropriate oxide and cap materials. [ABSTRACT FROM AUTHOR]

We present a particular generator polynomial for a cyclic redundancy check (CRC) code that can be used to detect all dominant error events in perpendicular recording over a broad range of densities. This polynomial is also effective in detecting error events that occur at codeword boundaries. The bit-error-rate and the sector-error-rate performances are validated that result from the use of the corresponding CRC code in conjunction with the well-known post-Viterbi error correction method. [ABSTRACT FROM AUTHOR]