| Title | Study of Current Density Phenomenon on Scratched Media Magnetic Disk |
| Author | *Yutthasak Todtong, Apirat Siritaratiwat (Khon Kaen University, Thailand) |
| Page | pp. 917 - 920 |
| Keyword | scratched media, current density |
| Abstract | In hard-disk drive industry, a media disk is one important part. It contains multilayer of various materials, i.e. magnetic, nonmagnetic, DLC etc [1]. In the production line, during a test performed, contamination or nano-particles can cause scratching on media disk. The size of scratch can be in a range of nanometer-millimeter. In this paper, a technique of current density applied to media disk is proposed in association with thermal observation. A constant current is applied to media disk and then a current density on detecting point is measured. A variation of bias current, detecting point and scratch depth is studied. |
| Title | Effect of Write Current and Capacitive Coupling on Write-Read Traces |
| Author | *Krisada Prachumrasee (Department of Electrical Engineering, Faculty of Engineering, Khon Kaen University, Thailand), Apirat Siritaratiwat (I/U CRC in HDD Component, Khon Kaen University, Thailand) |
| Page | pp. 921 - 924 |
| Keyword | Write-Current , Capacitive-Coupling , Write-Read Traces |
| Abstract | This study aims to investigate the effect of write-read coupling between write-read traces of recording head. It has been reported that a high data rate causes a serious coupling. Since a write-current is a main coupling source, the study of this current on the coupling is to investigate in association with the effect of capacitive-coupling. The results and discussions are explained. |
| Title | GUI-Based Read Channel Simulation Tools in Magnetic Recording System |
| Author | *Kitiyaporn Boonserm, Pornchai Supnithi (King Mongkut's Institute of Technology Ladkrabang, Thailand) |
| Page | pp. 925 - 928 |
| Keyword | Read Channel, Magnetic Recording System, GUI tools |
| Abstract | This paper presents a simulation and visualization tool for the read channel in magnetic recording system based on MATLAB and GUI tools. The system consists of read-back signal generator, low-pass filter (LPF), FIR equalizer, Viterbi detector and Graphical user interface (GUI) structure. Simulation results show the signals of each component in read channel model and users can modify important relevant parameters in each subsystem. |
| Title | An MMSE Infinite Impulse Response Equalizer for Perpendicular Recording Channels with Jittter Noise |
| Author | *Piya Kovintavewat (Nakhon Pathom Rajabhat University, Thailand), Chanon Warisarn, Pornchai Supnithi (King Mongkut's Institute of Technology Ladkrabang, Thailand) |
| Page | pp. 929 - 932 |
| Keyword | IIR equalizer, perpendicular recording, partial response target, jitter noise |
| Abstract | A finite impulse response (FIR) equalizer is practically
employed in conjunction with the Viterbi detector for
data detection process in magnetic recording channels. However,
the FIR equalizer with a large number of taps is required
at high density storage channels. It is well-known that an infinite
impulse response (IIR) filter with a small number of taps
can closely approximate such an FIR filter. In this paper, we
propose the IIR filter for perpendicular recording channels,
based on a minimum mean-squared error approach, and compare
its performance with the FIR equalizer in the presence
and in the absence of media jitter noise. Results indicate that
the IIR equalizer performs better than the FIR equalizer for
all jitter noise levels, especially when the number of equalizer
taps is small (e.g., 3 taps) and the normalized recording
density is high. |
| Title | The Performance Comparison Between DC-Full and DC-Attenuation Partial-Response Targets in Perpendicular Magnetic Recording Channel |
| Author | *Yupin Suppakhun, Pornchai Supnithi (King Mongkut's Institute of Technology Ladkrabang, Thailand) |
| Page | pp. 933 - 936 |
| Keyword | Perpendicular magnetic recording(PMR), dc-full target, dc-attenuation target, Noise-Predictive Maximum Likelihood(NPML) |
| Abstract | In this paper, we investigate the performance of perpendicular recording channel for dc-full and dc-attenuation partial response targets under the environment of electronics noise and jitter noise. We compare the performance of partial-response maximum-likelihood (PRML) and noise-predictive maximum–likelihood (NPML) detector for both types of targets. The NPML system is more suited for dc-attenuation targets, whereas the dc-full targets are suited to PRML system at low jitter noise. |
| Title | Improvement of Hard Disk Drive's Arm Bending Machine using Fuzzy Logic |
| Author | *Settha Tangkawanit (Naresuan University, Thailand), Somyot Kaitwanidvilai (King Mongkut's Institute of Technology Ladkrabang, Thailand), Surachet Kanprachar (Naresuan University, Thailand) |
| Page | pp. 937 - 940 |
| Keyword | hard disk drive, fuzzy logic, force control |
| Abstract | Hard Disk Drive’s arm (HDD’s arm) is one of the key elements in the HDD assembly. This element has to have the height of the arm measured from the reference be in the required range. To get such requirement, HDD’s arms have to pass to a bending machine in order to measure and adjust the height of the arms accordingly. Currently, if needed, a pre-defined bending force is applied to the arm. In this paper, the fuzzy logic rule to control the bending force is proposed. From the experimental data, it is found that the performance of the proposed technique in terms of the process capability index of the arm height error is superior to the conventional technique. |