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Downsampling (signal processing)

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The process of down sampling can be visualized as a two-step progression. The process starts as an input series x(n) that is processed by a filter h(n) to obtain the output sequence y(n) with reduced bandwidth. The sample rate of the output sequence is then reduced Q-to-1 to a rate commensurate with
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Fig 1: These graphs depict the spectral distributions of an oversampled function and the same function sampled at 1/3 the original rate. The bandwidth, B, in this example is just small enough that the slower sampling does not cause overlap (aliasing). Sometimes, a sampled function is resampled at a
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lower rate by keeping only every M sample and discarding the others, commonly called "decimation". Potential aliasing is prevented by lowpass-filtering the samples before decimation. The maximum filter bandwidth is tabulated in the bandwidth units used by the common filter design applications.
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outputs are being summed. This viewpoint offers a different implementation that might be advantageous in a multi-processor architecture. In other words, the input stream is demultiplexed and sent through a bank of M filters whose outputs are summed. When implemented that way, it is called a
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Sliusar I.I., Slyusar V.I., Voloshko S.V., Smolyar V.G. Next Generation Optical Access based on N-OFDM with decimation.// Third International Scientific-Practical Conference "Problems of Infocommunications. Science and Technology (PIC S&T'2016)". – Kharkiv. - October 3 –6, 2016.
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Realizable low-pass filters have a "skirt", where the response diminishes from near one to near zero.  In practice the cutoff frequency is placed far enough below the theoretical cutoff that the filter's skirt is contained below the theoretical
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T. Schilcher. RF applications in digital signal processing//" Digital signal processing". Proceedings, CERN Accelerator School, Sigtuna, Sweden, May 31-June 9, 2007. - Geneva, Switzerland: CERN (2008). - P. 258. - DOI: 10.5170/CERN-2008-003.
158:(i.e. high-frequency signal components will copy into the lower frequency band and be mistaken for lower frequencies). Step 1, when necessary, suppresses aliasing to an acceptable level. In this application, the filter is called an 670:{\displaystyle \underbrace {\sum _{n=-\infty }^{\infty }\overbrace {x(nT)} ^{x}\ \mathrm {e} ^{-\mathrm {i} 2\pi fnT}} _{\text{DTFT}}={\frac {1}{T}}\sum _{k=-\infty }^{\infty }X{\Bigl (}f-{\frac {k}{T}}{\Bigr )}.} 1841:
Sampling rate conversion systems are used to change the sampling rate of a signal. The process of sampling rate decrease is called decimation, and the process of sampling rate increase is called interpolation.
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Generally, this approach is applicable when the ratio Fy/Fx is a rational, or an irrational number, and is suitable for the sampling rate increase and for the sampling rate decrease.
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Saska Lindfors, Aarno Pärssinen, Kari A. I. Halonen. A 3-V 230-MHz CMOS Decimation Subsampler.// IEEE transactions on circuits and systems— Vol. 52, No. 2, February 2005. – P. 110.
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For completeness, we now mention that a possible, but unlikely, implementation of each phase is to replace the coefficients of the other phases with zeros in a copy of the
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the reduced signal bandwidth. In reality the processes of bandwidth reduction and sample rate reduction are merged in a single process called a multirate filter.
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such subsequences (phases) multiplexed together. The dot product is the sum of the dot products of each subsequence with the corresponding samples of the
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or a continuous function, it produces an approximation of the sequence that would have been obtained by sampling the signal at a lower rate (or
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only every tenth sample. This factor multiplies the sampling interval or, equivalently, divides the sampling rate. For example, if
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by a factor of 5/4, the resulting sample rate is 35,280. A system component that performs decimation is called a
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Decimators can be used to reduce the sampling frequency, whereas interpolators can be used to increase it.
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sequence at the input rate (which means multiplying by zeros), and decimate the output by a factor of
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can be explained as a two-step process, with an equivalent implementation that is more efficient:
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represents the input sequence being downsampled. In a general purpose processor, after computing
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used for the downsampling process has been accepted and used in many textbooks and fields.
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The periodic summation has been reduced in amplitude and periodicity by a factor of
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design, it relies on feedback from output to input, prior to the second step. With
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The process of reducing a sampling rate by an integer factor is referred to as
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output. The calculation performed by a decimating FIR filter for the
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Digital Signal Processing: Principles, Algorithms and Applications
1694:(2 ed.). Wellesley, MA: Wellesley-Cambridge Press. pp.  1529:(2nd ed.). Upper Saddle River, N.J.: Prentice Hall. p.  68:, or they can describe an entire process of bandwidth reduction ( 716:
in the formulas above gives the DTFT of the decimated sequence,
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dot products is never involved in the other dot products. Thus
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General techniques for sample-rate conversion by factor R ∈
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Reduce high-frequency signal components with a digital
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of a data sequence. We also refer to downsampling as
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Multirate Signal Processing for Communication Systems
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Handbook of Formulas and Tables for Signal Processing
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Decreasing the sampling rate is known as decimation.
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Impulse response coefficients taken at intervals of
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Step 1 requires a lowpass filter after increasing (
1687: 1522: 1455: 1392: 1279: 1179: 1090: 1022: 978: 902: 696: 669: 352:sequence. Furthermore, because of downsampling by 286: 1827:Multirate Filtering for Digital Signal Processing 1724:Multirate Filtering for Digital Signal Processing 1521:; Schafer, Ronald W.; Buck, John R. (1999). "4". 659: 636: 112:. Decimation by an integer factor is also called 2113: 1594: 1035:Increase (resample) the sequence by a factor of 368:low-order FIR filters are each filtering one of 1456:{\displaystyle X_{c}(i2\pi f)\triangleq X(f).} 162:, and its design is discussed below. Also see 1891: 1877: 325:, and recompute the dot product. In the case 181:, it is an easy matter to compute only every 1682: 1069:case, the anti-aliasing filter cutoff,  287:{\displaystyle y=\sum _{k=0}^{K-1}x\cdot h,} 1626:Poularikas, Alexander D. (September 1998). 1884: 1870: 1625: 1630:(1 ed.). CRC Press. pp. 42–48. 1619: 1280:{\displaystyle \Omega \triangleq 2\pi f,} 1167: 1016: 46:are terms associated with the process of 1794: 1588: 1511: 406: 317:is to advance the starting index in the 1775:Understanding Digital Signal Processing 1753: 1644: 997: 416: 14: 2114: 1758:(3rd ed.). India: Prentice-Hall. 1650: 301:sequence is the impulse response, and 86:is a term that historically means the 1865: 1824: 1772: 1721: 1715: 1676: 1006:denote the decimation factor, where: 1547: 173:When the anti-aliasing filter is an 124:Rate reduction by an integer factor 54:multi-rate digital signal processing 1710:No sensible engineer would do that. 1602:Multirate Digital Signal Processing 1553: 441:), whose samples at some interval, 360:samples involved in any one of the 80:, as in the case of a photograph). 24: 1747: 1726:. New York: Hershey. p. 192. 1376: 1372: 1363: 1338: 1333: 1310: 1259: 856: 851: 789: 780: 749: 744: 626: 621: 561: 552: 502: 497: 344:form a subsequence, and there are 104:audio at 44,100 samples/second is 25: 2138: 1829:. New York: Hershey. p. 35. 1197: 1091:{\displaystyle {\tfrac {0.5}{M}}} 166:for information about decimating 154:Step 2 alone creates undesirable 120:Downsampling by an integer factor 1922:Nyquist–Shannon sampling theorem 1180:{\displaystyle \mathbb {R} ^{+}} 933:) do not overlap each other is: 2008:Discrete-time Fourier transform 1686:; Nguyen, Truong (1996-10-01). 1525:Discrete-Time Signal Processing 1489: 1477: 1465: 1239: 1152: 1142: 451:discrete-time Fourier transform 1777:. Prentice Hall. p. 304. 1483: 1447: 1441: 1432: 1417: 1355: 1346: 1313: 1304: 1245: 1227: 1221: 1215: 1203: 1099:cycles per intermediate sample 814: 805: 772: 757: 542: 536: 523: 514: 278: 272: 263: 248: 212: 206: 18:Decimation (signal processing) 13: 1: 1953:Statistical signal processing 1556:"Upsampling and downsampling" 1504: 1471: 1248:. "4.2". p 143. eq 4.6, where 1233: 1209: 376:of the input stream, and the 313:, the easiest way to compute 1131:Visvalingam–Whyatt algorithm 1023:{\displaystyle \mathbb {Z} } 392:array, process the original 94:decimation by a factor of 10 92:. But in signal processing, 7: 1104: 146:; that is, keep only every 10: 2143: 2002:Discrete Fourier transform 1979:Matched Z-transform method 1795:Antoniou, Andreas (2006). 1495: 1101:, is the lower frequency. 89:removal of every tenth one 2122:Digital signal processing 2047: 1996:Discrete cosine transform 1961: 1930: 1899: 1893:Digital signal processing 1799:Digital Signal Processing 1754:Proakis, John G. (2000). 1690:Wavelets and Filter Banks 1486:. "4.6". p 171. fig 4.22. 1191:and the Farrow structure. 32:digital signal processing 2029:Post's inversion formula 1943:Digital image processing 1825:Milic, Ljiljana (2009). 1722:Milić, Ljiljana (2009). 1474:. "2.2". p 22. fig 2.10. 1189:polynomial interpolation 1136: 1050:Decimate by a factor of 1938:Audio signal processing 1803:. McGraw-Hill. p.  1773:Lyons, Richard (2001). 986:so that is the maximum 170:functions and signals. 142:the filtered signal by 64:can be synonymous with 1554:Tan, Li (2008-04-21). 1457: 1394: 1342: 1281: 1181: 1121:Sample-rate conversion 1092: 1024: 994:anti-aliasing filter. 980: 904: 860: 753: 698: 684:has units of seconds, 671: 630: 506: 413: 288: 244: 1654:(2004-05-24). "2.2". 1484:Oppenheim and Schafer 1458: 1395: 1319: 1282: 1246:Oppenheim and Schafer 1222:Crochiere and Rabiner 1182: 1093: 1025: 981: 905: 837: 730: 699: 672: 607: 483: 410: 333:can be designed as a 305:is its length.  289: 218: 2062:Anti-aliasing filter 1991:Constant-Q transform 1974:Advanced z-transform 1498:. "1.2.1". fig 12.2. 1404: 1291: 1256: 1224:"2". p 32. eq 2.55a. 1162: 1073: 1012: 998:By a rational factor 937: 727: 688: 476: 457:representation of a 417:Anti-aliasing filter 402:first Noble identity 200: 160:anti-aliasing filter 1652:Harris, Frederic J. 449:sequence. Then the 189:output sample is a 2019:Integral transform 2014:Impulse invariance 1986:Bilinear transform 1519:Oppenheim, Alan V. 1453: 1390: 1277: 1177: 1088: 1086: 1020: 976: 971: 956: 900: 890: 694: 667: 593: 586: 459:periodic summation 414: 284: 2127:Signal processing 2109: 2108: 2034:Starred transform 2024:Laplace transform 1948:Speech processing 1917:Estimation theory 1836:978-1-60566-178-0 1733:978-1-60566-178-0 1595:Crochiere, R.E.; 1400:  and   1360: 1085: 1039:. This is called 970: 955: 889: 835: 777: 697:{\displaystyle f} 655: 605: 591: 549: 546: 530: 481: 479: 433:of any function, 431:Fourier transform 27:Resampling method 16:(Redirected from 2134: 1907:Detection theory 1886: 1879: 1872: 1863: 1862: 1843: 1821: 1802: 1791: 1769: 1741: 1740: 1719: 1713: 1712: 1693: 1680: 1674: 1673: 1648: 1642: 1641: 1623: 1617: 1616: 1592: 1586: 1585: 1568: 1567: 1551: 1545: 1544: 1528: 1515: 1499: 1493: 1487: 1481: 1475: 1469: 1463: 1462: 1460: 1459: 1454: 1416: 1415: 1399: 1397: 1396: 1391: 1386: 1385: 1375: 1366: 1358: 1341: 1336: 1303: 1302: 1286: 1284: 1283: 1278: 1243: 1237: 1236:. "2.2.1". p 25. 1231: 1225: 1219: 1213: 1207: 1192: 1186: 1184: 1183: 1178: 1176: 1175: 1170: 1156: 1150: 1146: 1097: 1095: 1094: 1089: 1087: 1078: 1065: >  1031: 1029: 1027: 1026: 1021: 1019: 988:cutoff frequency 985: 983: 982: 977: 972: 963: 957: 948: 909: 907: 906: 901: 896: 892: 891: 888: 877: 859: 854: 836: 834: 823: 818: 817: 792: 783: 775: 752: 747: 703: 701: 700: 695: 676: 674: 673: 668: 663: 662: 656: 648: 640: 639: 629: 624: 606: 598: 592: 589: 587: 582: 581: 580: 564: 555: 547: 545: 531: 526: 509: 507: 505: 500: 356:, the stream of 335:half-band filter 293: 291: 290: 285: 243: 232: 21: 2142: 2141: 2137: 2136: 2135: 2133: 2132: 2131: 2112: 2111: 2110: 2105: 2043: 1957: 1926: 1912:Discrete signal 1895: 1890: 1837: 1815: 1785: 1766: 1750: 1748:Further reading 1745: 1744: 1734: 1720: 1716: 1706: 1684:Strang, Gilbert 1681: 1677: 1666: 1649: 1645: 1638: 1624: 1620: 1613: 1593: 1589: 1565: 1563: 1552: 1548: 1541: 1516: 1512: 1507: 1502: 1494: 1490: 1482: 1478: 1470: 1466: 1411: 1407: 1405: 1402: 1401: 1371: 1367: 1362: 1361: 1337: 1323: 1298: 1294: 1292: 1289: 1288: 1257: 1254: 1253: 1244: 1240: 1232: 1228: 1220: 1216: 1212:. "6.1". p 128. 1208: 1204: 1200: 1195: 1171: 1166: 1165: 1163: 1160: 1159: 1157: 1153: 1147: 1143: 1139: 1107: 1076: 1074: 1071: 1070: 1015: 1013: 1010: 1009: 1007: 1000: 961: 946: 938: 935: 934: 881: 875: 868: 864: 855: 841: 827: 822: 788: 784: 779: 778: 748: 734: 728: 725: 724: 689: 686: 685: 658: 657: 647: 635: 634: 625: 611: 597: 588: 560: 556: 551: 550: 532: 510: 508: 501: 487: 482: 480: 477: 474: 473: 419: 233: 222: 201: 198: 197: 122: 96:actually means 28: 23: 22: 15: 12: 11: 5: 2140: 2130: 2129: 2124: 2107: 2106: 2104: 2103: 2098: 2093: 2088: 2083: 2078: 2069: 2064: 2059: 2053: 2051: 2045: 2044: 2042: 2041: 2036: 2031: 2026: 2021: 2016: 2011: 2005: 1999: 1993: 1988: 1983: 1982: 1981: 1976: 1965: 1963: 1959: 1958: 1956: 1955: 1950: 1945: 1940: 1934: 1932: 1928: 1927: 1925: 1924: 1919: 1914: 1909: 1903: 1901: 1897: 1896: 1889: 1888: 1881: 1874: 1866: 1860: 1859: 1856: 1850: 1844: 1835: 1822: 1813: 1792: 1783: 1770: 1764: 1749: 1746: 1743: 1742: 1732: 1714: 1704: 1675: 1664: 1643: 1636: 1618: 1611: 1587: 1546: 1539: 1509: 1508: 1506: 1503: 1501: 1500: 1488: 1476: 1464: 1452: 1449: 1446: 1443: 1440: 1437: 1434: 1431: 1428: 1425: 1422: 1419: 1414: 1410: 1389: 1384: 1381: 1378: 1374: 1370: 1365: 1357: 1354: 1351: 1348: 1345: 1340: 1335: 1332: 1329: 1326: 1322: 1318: 1315: 1312: 1309: 1306: 1301: 1297: 1276: 1273: 1270: 1267: 1264: 1261: 1238: 1226: 1214: 1201: 1199: 1198:Page citations 1196: 1194: 1193: 1174: 1169: 1151: 1140: 1138: 1135: 1134: 1133: 1128: 1123: 1118: 1113: 1106: 1103: 1084: 1081: 1055: 1054: 1048: 1018: 999: 996: 975: 969: 966: 960: 954: 951: 945: 942: 911: 910: 899: 895: 887: 884: 880: 874: 871: 867: 863: 858: 853: 850: 847: 844: 840: 833: 830: 826: 821: 816: 813: 810: 807: 804: 801: 798: 795: 791: 787: 782: 774: 771: 768: 765: 762: 759: 756: 751: 746: 743: 740: 737: 733: 693: 678: 677: 666: 661: 654: 651: 646: 643: 638: 633: 628: 623: 620: 617: 614: 610: 604: 601: 596: 585: 579: 576: 573: 570: 567: 563: 559: 554: 544: 541: 538: 535: 529: 525: 522: 519: 516: 513: 504: 499: 496: 493: 490: 486: 455:Fourier series 418: 415: 295: 294: 283: 280: 277: 274: 271: 268: 265: 262: 259: 256: 253: 250: 247: 242: 239: 236: 231: 228: 225: 221: 217: 214: 211: 208: 205: 152: 151: 137: 134:lowpass filter 121: 118: 26: 9: 6: 4: 3: 2: 2139: 2128: 2125: 2123: 2120: 2119: 2117: 2102: 2099: 2097: 2096:Undersampling 2094: 2092: 2091:Sampling rate 2089: 2087: 2084: 2082: 2079: 2077: 2073: 2070: 2068: 2065: 2063: 2060: 2058: 2055: 2054: 2052: 2050: 2046: 2040: 2039:Zak transform 2037: 2035: 2032: 2030: 2027: 2025: 2022: 2020: 2017: 2015: 2012: 2009: 2006: 2003: 2000: 1997: 1994: 1992: 1989: 1987: 1984: 1980: 1977: 1975: 1972: 1971: 1970: 1967: 1966: 1964: 1960: 1954: 1951: 1949: 1946: 1944: 1941: 1939: 1936: 1935: 1933: 1929: 1923: 1920: 1918: 1915: 1913: 1910: 1908: 1905: 1904: 1902: 1898: 1894: 1887: 1882: 1880: 1875: 1873: 1868: 1867: 1864: 1857: 1855: 1851: 1849: 1845: 1842: 1838: 1832: 1828: 1823: 1820: 1816: 1814:0-07-145424-1 1810: 1806: 1801: 1800: 1793: 1790: 1786: 1784:0-201-63467-8 1780: 1776: 1771: 1767: 1761: 1757: 1752: 1751: 1739: 1735: 1729: 1725: 1718: 1711: 1707: 1701: 1697: 1692: 1691: 1685: 1679: 1672: 1667: 1661: 1657: 1653: 1647: 1639: 1633: 1629: 1622: 1614: 1608: 1604: 1603: 1599:(1983). "2". 1598: 1597:Rabiner, L.R. 1591: 1584: 1582: 1578: 1574: 1561: 1557: 1550: 1542: 1540:0-13-754920-2 1536: 1532: 1527: 1526: 1520: 1514: 1510: 1497: 1492: 1485: 1480: 1473: 1468: 1450: 1444: 1438: 1435: 1429: 1426: 1423: 1420: 1412: 1408: 1387: 1382: 1379: 1368: 1352: 1349: 1343: 1330: 1327: 1324: 1320: 1316: 1307: 1299: 1295: 1274: 1271: 1268: 1265: 1262: 1251: 1247: 1242: 1235: 1230: 1223: 1218: 1211: 1206: 1202: 1190: 1172: 1155: 1145: 1141: 1132: 1129: 1127: 1124: 1122: 1119: 1117: 1116:Posterization 1114: 1112: 1109: 1108: 1102: 1100: 1082: 1079: 1068: 1064: 1060: 1053: 1049: 1046: 1045:interpolation 1042: 1038: 1034: 1033: 1032: 1005: 995: 993: 989: 973: 967: 964: 958: 952: 949: 943: 940: 932: 928: 924: 920: 916: 897: 893: 885: 882: 878: 872: 869: 865: 861: 848: 845: 842: 838: 831: 828: 824: 819: 811: 808: 802: 799: 796: 793: 785: 769: 766: 763: 760: 754: 741: 738: 735: 731: 723: 722: 721: 719: 715: 711: 707: 704:has units of 691: 683: 664: 652: 649: 644: 641: 631: 618: 615: 612: 608: 602: 599: 594: 583: 577: 574: 571: 568: 565: 557: 539: 533: 527: 520: 517: 511: 494: 491: 488: 484: 472: 471: 470: 468: 464: 460: 456: 452: 448: 444: 440: 436: 432: 428: 424: 409: 405: 403: 399: 395: 391: 386: 384: 379: 375: 371: 367: 363: 359: 355: 351: 347: 343: 338: 336: 332: 328: 324: 320: 316: 312: 308: 304: 300: 281: 275: 269: 266: 260: 257: 254: 251: 245: 240: 237: 234: 229: 226: 223: 219: 215: 209: 203: 196: 195: 194: 192: 188: 184: 180: 179:FIR filtering 176: 171: 169: 165: 164:undersampling 161: 157: 149: 145: 141: 138: 135: 131: 130: 129: 127: 117: 115: 111: 107: 103: 99: 95: 91: 90: 85: 81: 79: 75: 71: 67: 63: 59: 56:system. Both 55: 51: 50: 45: 41: 37: 33: 19: 2086:Quantization 2081:Oversampling 2072:Nyquist rate 2067:Downsampling 2066: 1840: 1826: 1818: 1798: 1788: 1774: 1755: 1737: 1723: 1717: 1709: 1689: 1678: 1669: 1655: 1646: 1627: 1621: 1601: 1590: 1580: 1576: 1573:downsampling 1572: 1570: 1564:. Retrieved 1559: 1549: 1524: 1513: 1491: 1479: 1467: 1249: 1241: 1229: 1217: 1205: 1154: 1144: 1098: 1066: 1062: 1058: 1056: 1051: 1044: 1036: 1003: 1001: 991: 930: 926: 922: 918: 914: 912: 717: 713: 709: 708:. Replacing 681: 679: 466: 462: 453:(DTFT) is a 446: 445:, equal the 442: 438: 434: 426: 422: 420: 401: 397: 393: 389: 387: 382: 377: 373: 372:multiplexed 369: 365: 361: 357: 353: 349: 345: 341: 339: 330: 326: 322: 318: 314: 310: 306: 302: 298: 296: 186: 182: 172: 153: 147: 143: 139: 125: 123: 113: 109: 105: 102:compact disc 97: 93: 87: 83: 82: 73: 65: 61: 58:downsampling 57: 48: 43: 39: 36:downsampling 35: 29: 1969:Z-transform 1579:. The term 1560:eetimes.com 1472:Harris 2004 1234:Harris 2004 1210:Harris 2004 1030:; M > L. 191:dot product 114:compression 66:compression 40:compression 2116:Categories 2101:Upsampling 1962:Techniques 1931:Sub-fields 1765:8120311299 1705:0961408871 1665:0131465112 1637:0849385792 1612:0136051626 1581:decimation 1577:decimation 1566:2017-04-10 1562:. EE Times 1505:References 1111:Upsampling 1041:Upsampling 297:where the 84:Decimation 62:decimation 49:resampling 44:decimation 2076:frequency 1436:≜ 1427:π 1377:Ω 1369:− 1339:∞ 1334:∞ 1331:− 1321:∑ 1317:≜ 1311:Ω 1269:π 1263:≜ 1260:Ω 1059:expanding 959:⋅ 873:− 857:∞ 852:∞ 849:− 839:∑ 797:π 786:− 764:⋅ 750:∞ 745:∞ 742:− 732:∑ 645:− 627:∞ 622:∞ 619:− 609:∑ 584:⏟ 569:π 558:− 528:⏞ 503:∞ 498:∞ 495:− 485:∑ 429:) be the 383:polyphase 321:array by 267:⋅ 258:− 238:− 220:∑ 110:decimator 106:decimated 70:filtering 2057:Aliasing 2049:Sampling 1496:Tan 2008 1187:include 1126:Aliasing 1105:See also 385:filter. 168:bandpass 156:aliasing 140:Decimate 1287:  1149:cutoff. 1008:M, L ∈ 150:sample. 98:keeping 78:density 2010:(DTFT) 1900:Theory 1833:  1811:  1781:  1762:  1730:  1702:  1698:–101. 1662:  1634:  1609:  1537:  1359:  1252:  990:of an 776:  548:  374:phases 74:signal 42:, and 2004:(DFT) 1998:(DCT) 1137:Notes 1043:, or 992:ideal 712:with 706:hertz 680:When 52:in a 1831:ISBN 1809:ISBN 1779:ISBN 1760:ISBN 1728:ISBN 1700:ISBN 1660:ISBN 1632:ISBN 1607:ISBN 1535:ISBN 1002:Let 944:< 590:DTFT 421:Let 329:=2, 60:and 1805:830 1696:100 1531:168 1080:0.5 1004:M/L 950:0.5 469:): 461:of 175:IIR 30:In 2118:: 2074:/ 1839:. 1817:. 1807:. 1787:. 1736:. 1708:. 1668:. 1569:. 1558:. 1533:. 720:: 714:MT 193:: 116:. 38:, 34:, 1885:e 1878:t 1871:v 1768:. 1640:. 1615:. 1543:. 1451:. 1448:) 1445:f 1442:( 1439:X 1433:) 1430:f 1424:2 1421:i 1418:( 1413:c 1409:X 1388:, 1383:T 1380:n 1373:i 1364:e 1356:) 1353:T 1350:n 1347:( 1344:x 1328:= 1325:n 1314:) 1308:i 1305:( 1300:s 1296:X 1275:, 1272:f 1266:2 1250:: 1173:+ 1168:R 1083:M 1067:L 1063:M 1052:M 1047:. 1037:L 1017:Z 974:, 968:M 965:1 953:T 941:B 931:f 929:( 927:X 923:f 921:( 919:X 915:M 898:. 894:) 886:T 883:M 879:k 870:f 866:( 862:X 846:= 843:k 832:T 829:M 825:1 820:= 815:) 812:T 809:M 806:( 803:n 800:f 794:2 790:i 781:e 773:) 770:T 767:M 761:n 758:( 755:x 739:= 736:n 718:x 710:T 692:f 682:T 665:. 660:) 653:T 650:k 642:f 637:( 632:X 616:= 613:k 603:T 600:1 595:= 578:T 575:n 572:f 566:2 562:i 553:e 543:] 540:n 537:[ 534:x 524:) 521:T 518:n 515:( 512:x 492:= 489:n 467:f 465:( 463:X 447:x 443:T 439:t 437:( 435:x 427:f 425:( 423:X 398:M 394:x 390:h 378:M 370:M 366:M 362:M 358:x 354:M 350:x 346:M 342:M 331:h 327:M 323:M 319:x 315:y 311:y 307:x 303:K 299:h 282:, 279:] 276:k 273:[ 270:h 264:] 261:k 255:M 252:n 249:[ 246:x 241:1 235:K 230:0 227:= 224:k 216:= 213:] 210:n 207:[ 204:y 187:n 183:M 148:M 144:M 136:. 126:M 20:)

Index

Decimation (signal processing)
digital signal processing
resampling
multi-rate digital signal processing
filtering
density
removal of every tenth one
compact disc
lowpass filter
aliasing
anti-aliasing filter
undersampling
bandpass
IIR
FIR filtering
dot product
half-band filter

Fourier transform
discrete-time Fourier transform
Fourier series
periodic summation
hertz
cutoff frequency
Upsampling
Upsampling
Posterization
Sample-rate conversion
Aliasing
Visvalingam–Whyatt algorithm

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