Wat (wie) is PRML - definitie

METHOD FOR INTERPRETING DATA IN DIGITAL STORAGE SYSTEMS

PRML; Partial Response Maximum Likelihood; Partial response maximum likelihood

PRML

Partial Response - Maximum Likelihood (Reference: HDD)

Partial Response Maximum Likelihood

<storage> (PRML) A method for converting the weak analog signal from the head of a magnetic disk drive into a digital signal. PRML attempts to correctly interpret even small changes in the analog signal, whereas peak detection relies on fixed thresholds. Because PRML can correctly decode a weaker signal it allows higher density recording. For example, PRML would read the magnetic flux density pattern 70, 60, 55, 60, 70 as binary "101", and the same for 45, 40, 30, 40, 45. A peak detector would decode everything above, say, 50 as high, and below 50 as low, so the first pattern would read "111" and the second as "000". (1996-12-27)

Wikipedia

Partial-response maximum-likelihood

In computer data storage, partial-response maximum-likelihood (PRML) is a method for recovering the digital data from the weak analog read-back signal picked up by the head of a magnetic disk drive or tape drive. PRML was introduced to recover data more reliably or at a greater areal-density than earlier simpler schemes such as peak-detection. These advances are important because most of the digital data in the world is stored using magnetic storage on hard disk or tape drives.

Ampex introduced PRML in a tape drive in 1984. IBM introduced PRML in a disk drive in 1990 and also coined the acronym PRML. Many advances have taken place since the initial introduction. Recent read/write channels operate at much higher data-rates, are fully adaptive, and, in particular, include the ability to handle nonlinear signal distortion and non-stationary, colored, data-dependent noise (PDNP or NPML).

Partial response refers to the fact that part of the response to an individual bit may occur at one sample instant while other parts fall in other sample instants. Maximum-likelihood refers to the detector finding the bit-pattern most likely to have been responsible for the read-back waveform.

https://en.wikipedia.org/wiki/Partial-response maximum-likelihood

Voorbeelden uit tekstcorpus voor PRML

1. The World Bank said the 1''' Petroleum Revenue Management Law (PRML) was a legal condition of its agreeing to back a pipeline linking Chad to Cameroon‘s Atlantic coast.

2. If ratified by Deby, the changes to the PRML would "substantially weaken" the poverty reduction agenda mutually agreed by the World Bank and Chad, Wolfowitz said.

3. It noted that in return for bank funding, the government of Chad had promised not to amend any provisions of the law in ways that would "materially and adversely affect" the poverty–reduction strategy contained in the PRML.