Partial Response Maximum Likelihood


Also found in: Acronyms.

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".
References in periodicals archive ?
Marvell's 88E3061 Hex and 88E3081 Octal Fast Ethernet transceivers leverage technology developed through Marvell's first generation Physical Layer (PHY) transceivers as well as through its family of Alaska Gigabit Ethernet transceiver products and four generations of Partial Response Maximum Likelihood (PRML) read channels designed for the data storage market.
The EIM houses another key feature: the Advanced Partial Response Maximum Likelihood (PRML) channel.
This is accomplished by achieving rate efficiency of greater than 99 percent, making it one of the most efficient Partial Response Maximum Likelihood (PRML) implementations ever developed.
The ST L6361 integrates a Partial Response Maximum Likelihood (PRML) read channel path based on an advanced 16 state Viterbi detector and coding scheme to enhance signal-to-noise (SNR) performance.

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