Multilevel Run-Length Limited Recording on Read-Only Disc

Abstract

We use the holographic AdS/QCD soft-wall model to investigate the spectrum of scalar glueballs in a finite temperature plasma. In this model, glueballs are described by a massless scalar field in an AdS 5 black hole with a dilaton soft-wall background. Using AdS/CFT prescriptions, we compute the boundary retarded Green's function. The corresponding thermal spectral function shows quasiparticle peaks at low temperatures. We also compute the quasinormal modes of the scalar field in the soft-wall black hole geometry. The temperature and momentum dependences of these modes are analyzed. The positions and widths of the peaks of the spectral function are related to the frequencies of the quasinormal modes. Our numerical results are found employing the power series method and the computation of Breit-Wigner resonances.

Modulation Code and Signal Characteristics for Signal Waveform Modulation Optical Disc

“…The conventional modulation code used in binary optical data storage is the run-length-limited [RLLðd; kÞ] code, where d and k stipulate the number of zeros between two neighboring ones at least d and at most k. The M-aryðd; kÞ code 2,3) is developed for multilevel optical recording systems, such as the pit-depth modulation multilevel system 4) and pit depth and width modulation multilevel optical disc. 5) The parameter M denotes the level number, and d and k are the same as in RLLðd; kÞ. The main characteristic of the M-aryðd; kÞ code is that all of the runs have the same level number.…”

PRML Detection of Multi-Level DVD Channels with Run-Length-Limited Modulation

“…However, there are few publications related to this topic. Recently, experiments of ML-RLL modulation on DVD-ROM discs are carried out in Tsinghua University, and a multi-level DVD-ROM driver with conventional DVD optical pickup is also developed [12], [13], [14]. In this paper, we introduce the experimental results of four-level RLL modulation on DVD-ROM discs, and discuss the simulation performances of partial-response maximum-likelihood (PRML) detection for this optical recording channel.…”

New Efficient Run-Length Limited Code for Multilevel Read-Only Optical Disc

“…6,7) Since read-only (ROM) optical discs are very popular in consumer electronics market, it is important to investigate the feasibility of ML-RLL modulation on ROM-type optical discs. [8][9][10] However, general M-ary RLL codes result in consecutive multilevel pits on the ROM discs, and increase the difficulty of multilevel disc replication. More recently, a new class of M-ary RLL codes with constrained even nonzero symbols (ENS) is proposed to solve this problem.…”