Using a lattice decorrelator in the Partitioned FBLMS algorithm

Proceedings of the International Conference on Information, Communications and Signal Processing, ICICS21208-12120027

Mechanisms of Minimum Skew Angle Actuation for Hard Disk Drives

The utilization of voice coil motor (VCM) rotary actuator in hard disk drives (HDDs) results in skew angles between the read/write head and disk rotation direction. The system performance and achievable capacity of hard disk drives are excessively sensitive to the skew angle [1–3]. The difference in skew angle, between the ID to the OD can be as large as more than 30 degrees in conventional 3.5” and 2.5” VCM actuated HDDs. This paper presents three mechanisms, namely, a slant arm/suspension mechanism, a guider track mechanism, and a 4 link mechanism which can be designed to achieve minimum skew angle actuations for hard disk drives. The slant arm/suspension mechanism reduces the skew angle to ± 2 degrees in rotary actuated systems. The guider track mechanism further achieves the skew angle as zero degree theoretically. As an approximation of the guider track mechanism, the 4 link actuation mechanism reduces the skew angle to 0.4 degree. Their system dynamic behaviors are studied numerically using finite element modelling. Some of designs are prototyped and experimentally investigated

Mechanisms of Minimum Skew Angle Actuation for Hard Disk Drives

The utilization of voice coil motor (VCM) rotary actuator in hard disk drives (HDDs) results in skew angles between the read/write head and disk rotation direction. The system performance and achievable capacity of hard disk drives are excessively sensitive to the skew angle [1–3]. The difference in skew angle, between the ID to the OD can be as large as more than 30 degrees in conventional 3.5” and 2.5” VCM actuated HDDs. This paper presents three mechanisms, namely, a slant arm/suspension mechanism, a guider track mechanism, and a 4 link mechanism which can be designed to achieve minimum skew angle actuations for hard disk drives. The slant arm/suspension mechanism reduces the skew angle to ± 2 degrees in rotary actuated systems. The guider track mechanism further achieves the skew angle as zero degree theoretically. As an approximation of the guider track mechanism, the 4 link actuation mechanism reduces the skew angle to 0.4 degree. Their system dynamic behaviors are studied numerically using finite element modelling. Some of designs are prototyped and experimentally investigated

A general decoding framework for high-rate LDPC codes

This paper presents a hardware solution to the design of general low-density parity-check (LDPC) decoders, which simplifies the delivery network required by the message passing algorithm. While many designs of LDPC decoders for specific classes of codes exist in the literature, the design of a general LDPC decoder capable of supporting random LDPC codes is still challenging. The method proposed in this paper tries to pack different check node (CN) and variable node (VN) messages in the Tanner graph representation of the LDPC code, and is therefore called message packing. This method takes advantage of the fact that for high-rate LDPC’s the CN’s degree is much larger than the VN’s, and two distinct methods for delivering the messages to the CNs and VNs are proposed. Using the proposed interconnection network (IN) results in lower complexity decoding of LDPC codes when compared to other designs.Published versio