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Noise-predictive maximum-likelihood detection

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Viterbi algorithm, in which the branch-metric computation involves data-dependent noise prediction. Because the predictor coefficients and prediction error both depend on the local data pattern, the resulting structure has been called a data-dependent NPML detector. Reduced-state sequence detection schemes can be applied to data-dependent NPML, reducing implementation complexity.
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it correlated. A close match between the desired target polynomial and the physical channel can minimize losses. An effective way to achieve near optimal performance independently of the operating point—in terms of linear recording density—and the noise conditions is via noise prediction. In particular, the power of a stationary noise sequence
1571:(ARMA) stationary noise processes The concept was extended to include a variety of non-stationary noise sources, such as head, transition jitter and media noise; it was applied to various post-processing schemes. Noise prediction became an integral part of the metric computation in a wide variety of iterative detection/decoding schemes. 1503:
render the data-dependent medium noise a significant component of the total noise affecting performance. Because medium noise is correlated and data-dependent, information about noise and data patterns in past samples can provide information about noise in other samples. Thus, the concept of noise prediction for stationary
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In the absence of noise enhancement or noise correlation, the PRML sequence detector performs maximum-likelihood sequence estimation. As the operating point moves to higher linear recording densities, optimality declines with linear partial-response (PR) equalization, which enhances noise and renders
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error-correcting code. Moreover, the soft information computed by the decoder can be fed back again to the soft detector to improve detection performance. In this way it is possible to iteratively improve the error-rate performance at the decoder output in successive soft detection/decoding rounds.
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on which the Viterbi algorithm operates as well as tentative decisions corresponding to the path memory associated with each trellis state. NPML detectors can thus be viewed as reduced-state sequence-estimation detectors offering a range of implementation complexities. The complexity is governed by
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for channels with ISI has been derived. In particular, it when the data-dependent noise is conditionally Gauss–Markov, the branch metrics can be computed from the conditional second-order statistics of the noise process. In other words, the optimum MLSE can be implemented efficiently by using the
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Depending on the surface roughness and particle size, particulate media might exhibit nonstationary data-dependent transition or medium noise rather than colored stationary medium noise. Improvements o\in the quality of the readback head as well as the incorporation of low-noise preamplifiers may
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algorithm then NPML and NPML-like detection allow the computation of soft reliability information on individual code symbols, while retaining all the performance advantages associated with noise-predictive techniques. The soft information generated in this manner is used for soft decoding of the
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techniques were introduced into disk drives to improve the drive error-rate performance for operation at higher areal densities and for reducing manufacturing and servicing costs. In the early 1990s, partial-response class-4 (PR4) signal shaping in conjunction with maximum-likelihood sequence
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and coding established themselves as cost-efficient techniques for enabling additional increases in areal density while preserving reliability. Accordingly, the deployment of sophisticated detection schemes based on the concept of noise prediction are of paramount importance in the disk drive
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can be viewed as a family of reduced-state detectors with embedded feedback. These detectors exist in a form in which the decision-feedback path can be realized by simple table look-up operations, whereby the contents of these tables can be updated as a function of the operating conditions.
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An infinitely long predictor filter would lead to a sequence detector structure that requires an unbounded number of states. Therefore, finite-length predictors that render the noise at the input of the sequence detector approximately white are of interest.
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Analytical and experimental studies have shown that a judicious tradeoff between performance and state complexity leads to practical schemes with considerable performance gains. Thus, reduced-state approaches are promising for increasing linear density.
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line of HDD products in the late 1990s. Eventually, noise-predictive detection became a de facto standard and in its various instantiations became the core technology of the read channel module in HDD systems.
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Reduced-state sequence-detection schemes have been studied for application in the magnetic-recording channel and the references therein. For example, the NPML detectors with generalized PR target polynomials
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NPML and its various forms represent the core read-channel and detection technology used in recording systems employing advanced error-correcting codes that lend themselves to soft decoding, such as
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operator corresponds to a delay of one bit interval, at the output of a PR equalizer can be minimized by using an infinitely long predictor. A linear predictor with coefficients
1578:(PRML) and noise-predictive maximum-likelihood (NPML) detection and its impact on the industry were recognized in 2005 by the European Eduard Rhein Foundation Technology Award. 303: 143: 169:
denoting the maximum number of controlled ISI terms introduced by the combination of a partial-response shaping equalizer and the noise predictor. By judiciously choosing
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NPML detection was first described in 1996 and eventually found wide application in HDD read channel design. The “noise predictive” concept was later extended to handle
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Eleftheriou, E.; S. Ölçer; R. A. Hutchins (2010). "Adaptive Noise-Predictive Maximum-Likelihood (NPML) Data Detection for Magnetic Tape Storage Systems".
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The NPML family of sequence-estimation data detectors arise by embedding a noise prediction/whitening process into the branch metric computation of the
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Although advances in head and media technologies historically have been the driving forces behind the increases in the areal recording density,
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signal. NPML aims at minimizing the influence of noise in the detection process. Successfully applied, it allows recording data at higher
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Chevillat, P. R.; E. Eleftheriou (1989). "Decoding of Trellis-encoded Signals in the Presence of Intersymbol Interference and Noise".
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noise sources developed in can be naturally extended to the case where noise characteristics depend highly on local data patterns.
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Cideciyan, R. D.; J. D. Coker; E. Eleftheriou; R. L. Galbraith (2001). "NPML Detection Combined with Parity-Based Postprocessing".
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Caroselli, J.; S. A. Altekar; P. McEwen; J. K. Wolf (1997). "Improved Detection for Magnetic Recording Systems with Media Noise".
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Sonntag, J. L.; B. Vasic (2000). "Implementation and Bench Characterization of a Read Channel with Parity Check Postprocessor".
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The NPML detector is efficiently implemented via the Viterbi algorithm, which recursively computes the estimated data sequence.
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Eleftheriou, E.; W. Hirt (1996). "Noise-Predictive Maximum-Likelihood (NPML) Detection for the Magnetic Recording Channel".
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Bahl, L. R.; J. Cocke; F. Jelinek; J. Raviv (1974). "Optimal Decoding of Linear Codes for Minimizing Symbol Error Rate".
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Eyuboglu, V. M.; S. U. Qureshi (1998). "Reduced-state Sequence Estimation with Set Partitioning and Decision Feedback".
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Coker, J. D.; E. Eleftheriou; R. L. Galbraith; W. Hirt (1998). "Noise-Predictive Maximum Likelihood (NPML) Detection".
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Feng, W.; A. Vityaev; G. Burd; N. Nazari (2000). "On the performance of parity codes in magnetic recording systems".
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Chevillat, P.R.; E. Eleftheriou; D. Maiwald (1992). "Noise Predictive Partial-Response Equalizers and Applications".
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Cideciyan, R. D.; F. Dolivo; R. Hermann; W. Hirt; W. Schott (1992). "A PRML System for Digital Magnetic Recording".
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Kobayashi, H.; D. T. Tang (1970). "Application of Partial-Response Channel Coding to Magnetic Recording Systems".
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Eleftheriou, E. (2003). John G., Proakis (ed.). "Signal Processing for Magnetic-Recording Channels".
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Eleftheriou, E.; W. Hirt (1996). "Improving Performance of PRML/EPRML through Noise Prediction".
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Globecom '00 - IEEE. Global Telecommunications Conference. Conference Record (Cat. No.00CH37137)
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Eleftheriou, E; W. Hirt (1996). "Improving Performance of PRML/EPRML through Noise Prediction".
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Kobayashi, H. (1971). "Application of Probabilistic Decoding to Digital Magnetic Recording".
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Moon, J.; J. Park (2001). "Pattern-Dependent Noise Prediction in Signal-Dependent Noise".
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Duell-Hallen, A.; C. Heegard (1989). "Delayed Decision-feedback Sequence Estimation".
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Kavcic, A.; J. M. F. Moura (2000). "The Viterbi Algorithm and Markov Noise Memory".
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then this corresponds to the classical PR4 signal shaping. Using a whitening filter
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technique replaced the peak detection systems that used run-length-limited (RLL) (
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densities. It is used for retrieval of data recorded on magnetic media.
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the signal sequence at the output of the noise whitening filter
916:-state NPML detector if no reduced-state detection is employed. 34:
Data are read back by the read head, producing a weak and noisy
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symbols. In this case, the full-state NMPL detector performs
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a diagram of a Magnetic-recording system with NPML detection
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is a polynomial of order S and the noise-whitening filter
2392:"Marvell Contributes to Read-Rite's Areal Density Record" 1587: 1100:
and the effective ISI memory of the system is limited to
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is the one that minimizes the prediction error sequence
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By modeling the data-dependent noise as a finite-order
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Reliable operation of the process is achieved by using
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denotes the binary sequence of recorded data bits and
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(TMRC) 1640: 1638: 1636: 1634: 1632: 2144: 2142: 2084: 2082: 1935: 1933: 1931: 1777: 1749: 1709: 274: 261: 2406:"Samsung SV0802N hard drive specifications" 2109: 2021: 1818: 1816: 1814: 1812: 1644: 1586:NPML technology were first introduced into 2369:"Hitachi to Buy IBM's Hard Drive Business" 1629: 1596:Linear Tape Open (LTO) tape drive products 371:{\displaystyle {\acute {n}}\left(D\right)} 17:Noise-Predictive Maximum-Likelihood (NPML) 2139: 2118: 2079: 2035: 1985: 1983: 1981: 1979: 1928: 1653:. John Wiley & Sons, Inc.: 2247–2268. 974:{\displaystyle F\left(D\right)=1-{D^{2}}} 1809: 1647:Wiley Encyclopedia of Telecommunications 1594:In 2010, NPML was introduced into IBM's 2017: 2015: 2013: 1676: 1674: 1672: 1670: 1668: 1666: 1664: 1662: 1660: 42:. Alternatives include peak detection, 2417: 1976: 1530:(MAP) detection algorithm such as the 1136:maximum likelihood sequence estimation 583:or the optimum noise-whitening filter 338:produces the estimated noise sequence 305:,..., operating on the noise sequence 2366: 2010: 1657: 1016:, the generalized PR target becomes 2261:. Vol. 3. pp. 1877–1881. 1613:Partial-response maximum-likelihood 1576:partial-response maximum-likelihood 44:partial-response maximum-likelihood 13: 918: 14: 2441: 1574:The pioneering research work on 1171:-state trellis corresponding to 2398: 2389: 2383: 2360: 2336: 2311: 2250: 2215: 2200: 2169: 2052: 1581: 1552:detection, eventually known as 1543:Beginning in the 1980s several 298:{\displaystyle \{p_{l}\},l=1,2} 1901: 1866: 1831: 1410: 1404: 1373: 1367: 1222: 1189: 1183: 1001: 995: 803: 797: 770: 764: 660: 654: 323: 317: 215: 209: 1: 1825:Proc. IEEE Int. Conf. Commun. 1771:Proc. IEEE Int. Conf. Commun. 1623: 1569:autoregressive moving-average 138:{\displaystyle 0\leq K\leq M} 57: 25:magnetic data storage systems 2348:www.eduard-rhein-stiftung.de 2180:. 32 part 1 (5): 3968–3970. 1729:. 32 part 1 (5): 3968–3970. 7: 1601: 10: 2446: 2267:10.1109/GLOCOM.2000.891959 1538: 70:(ISI) with finite memory. 2430:Digital signal processing 2151:IEEE J. Sel. Areas Commun 2024:IEEE J. Sel. Areas Commun 1567:(AR) noise processes and 51:digital signal processing 21:digital signal-processing 2073:10.1109/TIT.1974.1055186 1803:10.1147/JRD.2010.2041034 1524:low-density parity check 68:intersymbol interference 2344:"Eduard Rhein Stiftung" 2319:"Technologiepreis 2005" 2061:IEEE Trans. Inf. Theory 1992:IEEE Trans. Inf. Theory 1164:{\displaystyle 2^{L+2}} 907:{\displaystyle 2^{L}+S} 675:in a mean-square sense 1490: 1417: 1380: 1347: 1196: 1165: 1128: 1091: 1008: 975: 924: 908: 870: 834: 818:has a finite order of 810: 777: 743: 667: 633: 574: 495: 372: 330: 299: 246: 222: 185: 161: 139: 105: 1491: 1418: 1381: 1348: 1197: 1166: 1129: 1127:{\displaystyle M=L+2} 1092: 1009: 976: 922: 909: 871: 869:{\displaystyle M=L+S} 835: 811: 778: 744: 668: 634: 575: 496: 373: 331: 300: 247: 223: 186: 162: 140: 106: 104:{\displaystyle 2^{K}} 27:that operate at high 23:methods suitable for 1528:maximum a posteriori 1435: 1416:{\displaystyle W(D)} 1398: 1379:{\displaystyle a(D)} 1361: 1213: 1195:{\displaystyle G(D)} 1177: 1142: 1106: 1022: 1007:{\displaystyle W(D)} 989: 933: 885: 848: 824: 809:{\displaystyle W(D)} 791: 776:{\displaystyle F(D)} 758: 688: 666:{\displaystyle e(D)} 648: 589: 509: 384: 342: 329:{\displaystyle n(D)} 311: 258: 236: 221:{\displaystyle n(D)} 203: 175: 151: 117: 88: 2236:2001ITM....37..714C 2186:1996ITM....32.3968E 2133:10.1147/rd.151.0064 2103:10.1147/rd.144.0368 1954:1997ITM....33.2779C 1887:1989ITCom..37..428D 1852:1988ITCom..36...13E 1797:(2, paper 7): 7:1. 1735:1996ITM....32.3968E 1695:1998ITM....34..110C 1910:IEEE Trans. Commun 1875:IEEE Trans. Commun 1840:IEEE Trans. Commun 1608:Maximum likelihood 1486: 1413: 1376: 1343: 1192: 1161: 1124: 1087: 1004: 971: 927:As an example, if 925: 904: 866: 830: 806: 773: 739: 663: 629: 570: 491: 368: 326: 295: 242: 218: 181: 157: 135: 101: 2276:978-0-7803-6451-6 2244:10.1109/20.917606 2194:10.1109/20.539233 2163:10.1109/49.124468 2046:10.1109/49.920181 2004:10.1109/18.817531 1962:10.1109/20.617728 1743:10.1109/20.539233 1703:10.1109/20.663468 1618:Viterbi algorithm 1253: 1225: 1138:(MLSE) using the 833:{\displaystyle L} 430: 354: 245:{\displaystyle D} 184:{\displaystyle K} 160:{\displaystyle M} 64:Viterbi algorithm 2437: 2425:Hard disk drives 2410: 2409: 2402: 2396: 2395: 2387: 2381: 2380: 2378: 2376: 2364: 2358: 2357: 2355: 2354: 2340: 2334: 2333: 2331: 2330: 2321:. Archived from 2315: 2309: 2308: 2302: 2298: 2296: 2288: 2254: 2248: 2247: 2224:IEEE Trans. Magn 2219: 2213: 2212: 2204: 2198: 2197: 2178:IEEE Trans. Magn 2173: 2167: 2166: 2146: 2137: 2136: 2116: 2107: 2106: 2086: 2077: 2076: 2056: 2050: 2049: 2039: 2019: 2008: 2007: 1987: 1974: 1973: 1948:(5): 2779–2781. 1942:IEEE Trans. Magn 1937: 1926: 1925: 1922:10.1109/26.31158 1905: 1899: 1898: 1895:10.1109/26.24594 1870: 1864: 1863: 1835: 1829: 1828: 1820: 1807: 1806: 1786: 1775: 1774: 1766: 1747: 1746: 1727:IEEE Trans. Magn 1722: 1707: 1706: 1683:IEEE Trans. Magn 1678: 1655: 1654: 1642: 1547:-processing and 1495: 1493: 1492: 1487: 1485: 1468: 1451: 1424: 1422: 1420: 1419: 1414: 1387: 1385: 1383: 1382: 1377: 1352: 1350: 1349: 1344: 1342: 1341: 1340: 1328: 1314: 1297: 1280: 1279: 1278: 1251: 1238: 1227: 1226: 1218: 1203: 1201: 1199: 1198: 1193: 1170: 1168: 1167: 1162: 1160: 1159: 1133: 1131: 1130: 1125: 1096: 1094: 1093: 1088: 1086: 1069: 1065: 1064: 1063: 1062: 1038: 1015: 1013: 1011: 1010: 1005: 980: 978: 977: 972: 970: 969: 968: 949: 915: 913: 911: 910: 905: 897: 896: 875: 873: 872: 867: 841: 839: 837: 836: 831: 817: 815: 813: 812: 807: 784: 782: 780: 779: 774: 748: 746: 745: 740: 738: 721: 704: 674: 672: 670: 669: 664: 638: 636: 635: 630: 628: 605: 579: 577: 576: 571: 566: 565: 564: 554: 553: 538: 537: 525: 500: 498: 497: 492: 490: 486: 485: 460: 443: 432: 431: 423: 417: 400: 377: 375: 374: 369: 367: 356: 355: 347: 337: 335: 333: 332: 327: 304: 302: 301: 296: 273: 272: 253: 251: 249: 248: 243: 229: 227: 225: 224: 219: 192: 190: 188: 187: 182: 168: 166: 164: 163: 158: 144: 142: 141: 136: 112: 110: 108: 107: 102: 100: 99: 29:linear recording 2445: 2444: 2440: 2439: 2438: 2436: 2435: 2434: 2415: 2414: 2413: 2404: 2403: 2399: 2388: 2384: 2374: 2372: 2367:Popovich, Ken. 2365: 2361: 2352: 2350: 2342: 2341: 2337: 2328: 2326: 2317: 2316: 2312: 2300: 2299: 2290: 2289: 2277: 2255: 2251: 2220: 2216: 2205: 2201: 2174: 2170: 2147: 2140: 2121:IBM J. Res. Dev 2117: 2110: 2091:IBM J. Res. Dev 2087: 2080: 2057: 2053: 2020: 2011: 1988: 1977: 1938: 1929: 1906: 1902: 1871: 1867: 1860:10.1109/26.2724 1836: 1832: 1821: 1810: 1791:IBM J. Res. Dev 1787: 1778: 1767: 1750: 1723: 1710: 1679: 1658: 1643: 1630: 1626: 1604: 1584: 1541: 1475: 1458: 1441: 1436: 1433: 1432: 1399: 1396: 1395: 1393: 1362: 1359: 1358: 1356: 1336: 1333: 1332: 1318: 1304: 1287: 1268: 1264: 1260: 1228: 1217: 1216: 1214: 1211: 1210: 1178: 1175: 1174: 1172: 1149: 1145: 1143: 1140: 1139: 1107: 1104: 1103: 1076: 1058: 1054: 1053: 1046: 1042: 1028: 1023: 1020: 1019: 990: 987: 986: 984: 964: 960: 959: 939: 934: 931: 930: 892: 888: 886: 883: 882: 880: 849: 846: 845: 825: 822: 821: 819: 792: 789: 788: 786: 759: 756: 755: 753: 728: 711: 694: 689: 686: 685: 649: 646: 645: 643: 618: 595: 590: 587: 586: 560: 556: 555: 549: 545: 533: 529: 515: 510: 507: 506: 475: 465: 461: 450: 433: 422: 421: 407: 390: 385: 382: 381: 357: 346: 345: 343: 340: 339: 312: 309: 308: 306: 268: 264: 259: 256: 255: 237: 234: 233: 231: 204: 201: 200: 198: 176: 173: 172: 170: 152: 149: 148: 146: 118: 115: 114: 95: 91: 89: 86: 85: 83: 60: 40:areal densities 19:is a class of 12: 11: 5: 2443: 2433: 2432: 2427: 2412: 2411: 2397: 2382: 2359: 2335: 2310: 2301:|journal= 2275: 2249: 2230:(2): 714–720. 2214: 2199: 2168: 2138: 2108: 2097:(4): 368–375. 2078: 2067:(2): 284–287. 2051: 2037:10.1.1.16.6310 2030:(4): 730–743. 2009: 1975: 1927: 1916:(7): 669–676. 1900: 1881:(5): 428–436. 1865: 1830: 1808: 1776: 1748: 1708: 1689:(1): 110–117. 1656: 1627: 1625: 1622: 1621: 1620: 1615: 1610: 1603: 1600: 1583: 1580: 1565:autoregressive 1545:digital signal 1540: 1537: 1514:, the optimum 1512:Markov process 1484: 1481: 1478: 1474: 1471: 1467: 1464: 1461: 1457: 1454: 1450: 1447: 1444: 1440: 1412: 1409: 1406: 1403: 1375: 1372: 1369: 1366: 1339: 1335: 1331: 1327: 1324: 1321: 1317: 1313: 1310: 1307: 1303: 1300: 1296: 1293: 1290: 1286: 1283: 1277: 1274: 1271: 1267: 1263: 1259: 1256: 1250: 1247: 1244: 1241: 1237: 1234: 1231: 1224: 1221: 1191: 1188: 1185: 1182: 1158: 1155: 1152: 1148: 1123: 1120: 1117: 1114: 1111: 1085: 1082: 1079: 1075: 1072: 1068: 1061: 1057: 1052: 1049: 1045: 1041: 1037: 1034: 1031: 1027: 1003: 1000: 997: 994: 967: 963: 958: 955: 952: 948: 945: 942: 938: 903: 900: 895: 891: 865: 862: 859: 856: 853: 829: 805: 802: 799: 796: 772: 769: 766: 763: 737: 734: 731: 727: 724: 720: 717: 714: 710: 707: 703: 700: 697: 693: 662: 659: 656: 653: 627: 624: 621: 617: 614: 611: 608: 604: 601: 598: 594: 569: 563: 559: 552: 548: 544: 541: 536: 532: 528: 524: 521: 518: 514: 489: 484: 481: 478: 474: 471: 468: 464: 459: 456: 453: 449: 446: 442: 439: 436: 429: 426: 420: 416: 413: 410: 406: 403: 399: 396: 393: 389: 366: 363: 360: 353: 350: 325: 322: 319: 316: 294: 291: 288: 285: 282: 279: 276: 271: 267: 263: 241: 217: 214: 211: 208: 180: 156: 134: 131: 128: 125: 122: 98: 94: 59: 56: 9: 6: 4: 3: 2: 2442: 2431: 2428: 2426: 2423: 2422: 2420: 2407: 2401: 2393: 2390:Yoo, Daniel. 2386: 2371:. PC Magazine 2370: 2363: 2349: 2345: 2339: 2325:on 2011-07-18 2324: 2320: 2314: 2306: 2294: 2286: 2282: 2278: 2272: 2268: 2264: 2260: 2253: 2245: 2241: 2237: 2233: 2229: 2225: 2218: 2210: 2203: 2195: 2191: 2187: 2183: 2179: 2172: 2164: 2160: 2156: 2152: 2145: 2143: 2134: 2130: 2126: 2122: 2115: 2113: 2104: 2100: 2096: 2092: 2085: 2083: 2074: 2070: 2066: 2062: 2055: 2047: 2043: 2038: 2033: 2029: 2025: 2018: 2016: 2014: 2005: 2001: 1997: 1993: 1986: 1984: 1982: 1980: 1971: 1967: 1963: 1959: 1955: 1951: 1947: 1943: 1936: 1934: 1932: 1923: 1919: 1915: 1911: 1904: 1896: 1892: 1888: 1884: 1880: 1876: 1869: 1861: 1857: 1853: 1849: 1845: 1841: 1834: 1826: 1819: 1817: 1815: 1813: 1804: 1800: 1796: 1792: 1785: 1783: 1781: 1772: 1765: 1763: 1761: 1759: 1757: 1755: 1753: 1744: 1740: 1736: 1732: 1728: 1721: 1719: 1717: 1715: 1713: 1704: 1700: 1696: 1692: 1688: 1684: 1677: 1675: 1673: 1671: 1669: 1667: 1665: 1663: 1661: 1652: 1648: 1641: 1639: 1637: 1635: 1633: 1628: 1619: 1616: 1614: 1611: 1609: 1606: 1605: 1599: 1597: 1592: 1589: 1579: 1577: 1572: 1570: 1566: 1561: 1559: 1555: 1550: 1546: 1536: 1533: 1529: 1525: 1520: 1517: 1513: 1508: 1506: 1500: 1496: 1482: 1479: 1476: 1472: 1469: 1465: 1462: 1459: 1455: 1452: 1448: 1445: 1442: 1438: 1430: 1426: 1407: 1401: 1391: 1370: 1364: 1353: 1337: 1334: 1329: 1325: 1322: 1319: 1315: 1311: 1308: 1305: 1301: 1298: 1294: 1291: 1288: 1284: 1281: 1275: 1272: 1269: 1265: 1261: 1257: 1254: 1248: 1245: 1242: 1239: 1235: 1232: 1229: 1219: 1208: 1205: 1186: 1180: 1156: 1153: 1150: 1146: 1137: 1121: 1118: 1115: 1112: 1109: 1101: 1098: 1083: 1080: 1077: 1073: 1070: 1066: 1059: 1055: 1050: 1047: 1043: 1039: 1035: 1032: 1029: 1025: 1017: 998: 992: 981: 965: 961: 956: 953: 950: 946: 943: 940: 936: 928: 921: 917: 901: 898: 893: 889: 877: 863: 860: 857: 854: 851: 843: 827: 800: 794: 767: 761: 750: 735: 732: 729: 725: 722: 718: 715: 712: 708: 705: 701: 698: 695: 691: 683: 680: 676: 657: 651: 640: 625: 622: 619: 615: 612: 609: 606: 602: 599: 596: 592: 584: 581: 567: 561: 557: 550: 546: 542: 539: 534: 530: 526: 522: 519: 516: 512: 504: 501: 487: 482: 479: 476: 472: 469: 466: 462: 457: 454: 451: 447: 444: 440: 437: 434: 427: 424: 418: 414: 411: 408: 404: 401: 397: 394: 391: 387: 379: 364: 361: 358: 351: 348: 320: 314: 292: 289: 286: 283: 280: 277: 269: 265: 239: 212: 206: 194: 178: 154: 132: 129: 126: 123: 120: 96: 92: 80: 76: 71: 69: 65: 55: 52: 47: 45: 41: 37: 32: 30: 26: 22: 18: 2400: 2385: 2373:. 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Marvell. 2353:2017-07-04 2329:2012-07-26 1827:: 942–947. 1773:: 556–560. 1624:References 58:Principles 54:industry. 2303:ignored ( 2293:cite book 2157:: 38–56. 2127:: 65–74. 2032:CiteSeerX 1846:: 13–20. 1470:× 1330:∥ 1299:− 1282:∥ 1223:^ 1071:× 1051:− 957:− 723:× 613:− 470:− 428:´ 419:− 352:´ 130:≤ 124:≤ 2285:42438542 1970:42451727 1602:See also 1505:Gaussian 2375:June 5, 2232:Bibcode 2182:Bibcode 1950:Bibcode 1883:Bibcode 1848:Bibcode 1731:Bibcode 1691:Bibcode 1539:History 1423:⁠ 1394:⁠ 1386:⁠ 1357:⁠ 1202:⁠ 1173:⁠ 1014:⁠ 985:⁠ 914:⁠ 881:⁠ 840:⁠ 820:⁠ 816:⁠ 787:⁠ 783:⁠ 754:⁠ 673:⁠ 644:⁠ 336:⁠ 307:⁠ 252:⁠ 232:⁠ 228:⁠ 199:⁠ 191:⁠ 171:⁠ 167:⁠ 147:⁠ 145:, with 111:⁠ 84:⁠ 79:trellis 2283:  2273:  2034:  1968:  1549:coding 1355:where 1252:  752:where 36:analog 2281:S2CID 1966:S2CID 1588:IBM's 2377:2002 2305:help 2271:ISBN 1554:PRML 1532:BCJR 1516:MLSE 1390:z(D) 580:... 2263:doi 2240:doi 2190:doi 2159:doi 2129:doi 2099:doi 2069:doi 2042:doi 2000:doi 1958:doi 1918:doi 1891:doi 1856:doi 1799:doi 1739:doi 1699:doi 1558:d,k 2421:: 2346:. 2297:: 2295:}} 2291:{{ 2279:. 2269:. 2238:. 2228:37 2226:. 2188:. 2155:10 2153:. 2141:^ 2125:15 2123:. 2111:^ 2095:14 2093:. 2081:^ 2065:20 2063:. 2040:. 2028:19 2026:. 2012:^ 1996:46 1994:. 1978:^ 1964:. 1956:. 1946:33 1944:. 1930:^ 1914:37 1912:. 1889:. 1879:37 1877:. 1854:. 1844:36 1842:. 1811:^ 1795:54 1793:. 1779:^ 1751:^ 1737:. 1711:^ 1697:. 1687:34 1685:. 1659:^ 1649:. 1631:^ 1425:. 1204:. 1097:, 876:, 749:, 639:, 113:, 2408:. 2379:. 2356:. 2332:. 2307:) 2287:. 2265:: 2246:. 2242:: 2234:: 2211:. 2196:. 2192:: 2184:: 2165:. 2161:: 2135:. 2131:: 2105:. 2101:: 2075:. 2071:: 2048:. 2044:: 2006:. 2002:: 1972:. 1960:: 1952:: 1924:. 1920:: 1897:. 1893:: 1885:: 1862:. 1858:: 1850:: 1805:. 1801:: 1745:. 1741:: 1733:: 1705:. 1701:: 1693:: 1651:4 1483:) 1480:D 1477:( 1473:W 1466:) 1463:D 1460:( 1456:F 1453:= 1449:) 1446:D 1443:( 1439:G 1411:) 1408:D 1405:( 1402:W 1374:) 1371:D 1368:( 1365:a 1338:2 1326:) 1323:D 1320:( 1316:G 1312:) 1309:D 1306:( 1302:a 1295:) 1292:D 1289:( 1285:z 1276:) 1273:D 1270:( 1266:a 1262:n 1258:i 1255:m 1249:g 1246:r 1243:a 1240:= 1236:) 1233:D 1230:( 1220:a 1190:) 1187:D 1184:( 1181:G 1157:2 1154:+ 1151:L 1147:2 1122:2 1119:+ 1116:L 1113:= 1110:M 1084:) 1081:D 1078:( 1074:W 1067:) 1060:2 1056:D 1048:1 1044:( 1040:= 1036:) 1033:D 1030:( 1026:G 1002:) 999:D 996:( 993:W 966:2 962:D 954:1 951:= 947:) 944:D 941:( 937:F 902:S 899:+ 894:L 890:2 864:S 861:+ 858:L 855:= 852:M 828:L 804:) 801:D 798:( 795:W 771:) 768:D 765:( 762:F 736:) 733:D 730:( 726:W 719:) 716:D 713:( 709:F 706:= 702:) 699:D 696:( 692:G 661:) 658:D 655:( 652:e 626:) 623:D 620:( 616:P 610:1 607:= 603:) 600:D 597:( 593:W 568:+ 562:2 558:D 551:2 547:p 543:+ 540:D 535:1 531:p 527:= 523:) 520:D 517:( 513:P 488:) 483:) 480:D 477:( 473:P 467:1 463:( 458:) 455:D 452:( 448:n 445:= 441:) 438:D 435:( 425:n 415:) 412:D 409:( 405:n 402:= 398:) 395:D 392:( 388:e 365:) 362:D 359:( 349:n 324:) 321:D 318:( 315:n 293:2 290:, 287:1 284:= 281:l 278:, 275:} 270:l 266:p 262:{ 240:D 216:) 213:D 210:( 207:n 179:K 155:M 133:M 127:K 121:0 97:K 93:2

Index

digital signal-processing
magnetic data storage systems
linear recording
analog
areal densities
partial-response maximum-likelihood
digital signal processing
Viterbi algorithm
intersymbol interference
hypothesized
trellis
a diagram of a Magnetic-recording system with NPML detection
maximum likelihood sequence estimation
Gaussian
Markov process
MLSE
low-density parity check
maximum a posteriori
BCJR
digital signal
coding
PRML
autoregressive
autoregressive moving-average
partial-response maximum-likelihood
IBM's
Linear Tape Open (LTO) tape drive products
Maximum likelihood
Partial-response maximum-likelihood
Viterbi algorithm

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