{"id":1514,"date":"2026-10-27T04:00:00","date_gmt":"2026-10-26T19:00:00","guid":{"rendered":"https:\/\/quantumsea.net\/?p=1514"},"modified":"2026-10-26T22:34:13","modified_gmt":"2026-10-26T13:34:13","slug":"qs-johnson-noise-bandwidth-20261024","status":"publish","type":"post","link":"https:\/\/quantumsea.net\/?p=1514","title":{"rendered":"\u30b8\u30e7\u30f3\u30bd\u30f3\u96d1\u97f3\u3001\u62b5\u6297\u306e\u71b1\u96d1\u97f3\u96fb\u5727\u306f\u5e2f\u57df\u5e45\u3067\u3069\u3046\u5909\u308f\u308b\u304b"},"content":{"rendered":"<p>\u30bb\u30f3\u30b5\u30fc\u306e\u5c0f\u3055\u306a\u96fb\u5727\u3092\u6e2c\u308b\u3068\u304d\u3001\u6e2c\u5b9a\u5668\u306e\u5e2f\u57df\u5e45\u3092\u5e83\u3052\u308b\u3068\u3001\u4fe1\u53f7\u306e\u901f\u3044\u5909\u5316\u3092\u8ffd\u3044\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002\u3057\u304b\u3057\u3001\u8868\u793a\u306e\u63fa\u3089\u304e\u307e\u3067\u5927\u304d\u304f\u306a\u308b\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u3002\u5468\u6ce2\u6570\u306e\u5e83\u3044\u7bc4\u56f2\u306b\u5206\u5e03\u3059\u308b\u96d1\u97f3\u3082\u3001\u4e00\u7dd2\u306b\u53d6\u308a\u8fbc\u3080\u305f\u3081\u3067\u3059\u3002<\/p>\n<p>\u305d\u306e\u57fa\u672c\u7684\u306a\u4e00\u3064\u304c\u3001\u62b5\u6297\u3067\u751f\u3058\u308b<strong>\u30b8\u30e7\u30f3\u30bd\u30f3\u96d1\u97f3\uff08\u71b1\u96d1\u97f3\uff09<\/strong>\u3067\u3059\u3002\u5916\u304b\u3089\u4fe1\u53f7\u3092\u52a0\u3048\u306a\u304f\u3066\u3082\u3001\u6e29\u5ea6\u3092\u6301\u3064\u62b5\u6297\u306b\u306f\u96fb\u6c17\u7684\u306a\u63fa\u3089\u304e\u304c\u3042\u308a\u307e\u3059\u3002\u3053\u3053\u3067\u306f\u62b5\u6297\u305d\u306e\u3082\u306e\u306e\u96d1\u97f3\u306b\u7d5e\u308a\u3001\u300c\u5e2f\u57df\u5e45\u3092\u4f55\u500d\u306b\u3059\u308b\u3068\u3001\u6e2c\u308b\u96fb\u5727\u306e\u63fa\u3089\u304e\u306f\u4f55\u500d\u306b\u306a\u308b\u304b\u300d\u3092\u8a08\u7b97\u3057\u307e\u3059\u3002<\/p>\n<section class=\"influvetor-quick-summary\">\n<p><strong>\u7c21\u5358\u306b\u307e\u3068\u3081\u308b\u3068\uff1f<\/strong><\/p>\n<ul>\n<li>\u62b5\u6297\u306e\u71b1\u96d1\u97f3\u306f\u3001\u5e73\u5747\u96fb\u5727\u304c\u30bc\u30ed\u3067\u3082\u6d88\u3048\u307e\u305b\u3093\u3002\u5927\u304d\u3055\u306f\u96fb\u5727\u3092\u4e8c\u4e57\u3057\u3066\u5e73\u5747\u3057\u3001\u5e73\u65b9\u6839\u3092\u53d6\u3063\u305f\u5b9f\u52b9\u5024\u3067\u6bd4\u3079\u307e\u3059\u3002<\/li>\n<li>\u540c\u3058\u6e29\u5ea6\u3068\u62b5\u6297\u306a\u3089\u3001\u7406\u60f3\u7684\u306a\u901a\u904e\u5e2f\u57df\u3092100\u500d\u306b\u3059\u308b\u3068\u3001\u96d1\u97f3\u96fb\u5727\u306e\u5b9f\u52b9\u5024\u306f10\u500d\u306b\u306a\u308a\u307e\u3059\u3002<\/li>\n<li>\u5b9f\u969b\u306e\u30d5\u30a3\u30eb\u30bf\u30fc\u3067\u306f\u3001\u906e\u65ad\u5468\u6ce2\u6570\u3088\u308a\u9ad8\u3044\u6210\u5206\u3082\u5c11\u3057\u901a\u308a\u307e\u3059\u3002\u96d1\u97f3\u306e\u8a08\u7b97\u306b\u306f\u3001\u30d5\u30a3\u30eb\u30bf\u30fc\u306e\u5f62\u3092\u542b\u3081\u305f\u300c\u7b49\u4fa1\u96d1\u97f3\u5e2f\u57df\u5e45\u300d\u304c\u5fc5\u8981\u3067\u3059\u3002<\/li>\n<\/ul>\n<\/section>\n<h2>\u5e73\u5747\u304c\u30bc\u30ed\u3067\u3082\u3001\u96fb\u5727\u306e\u63fa\u3089\u304e\u306f\u6b8b\u308b<\/h2>\n<p>\u96d1\u97f3\u96fb\u5727\u306f\u6b63\u8ca0\u306b\u63fa\u308c\u308b\u305f\u3081\u3001\u5341\u5206\u306a\u6642\u9593\u306b\u308f\u305f\u3063\u3066\u5e73\u5747\u3059\u308b\u3068\u30bc\u30ed\u3078\u8fd1\u3065\u304f\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002\u305d\u308c\u3067\u3082\u77ac\u9593\u3054\u3068\u306e\u5024\u304c\u30bc\u30ed\u306b\u306a\u308b\u308f\u3051\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u6b63\u8ca0\u3092\u6253\u3061\u6d88\u3055\u305a\u306b\u5927\u304d\u3055\u3092\u6e2c\u308b\u306b\u306f\u3001\u96fb\u5727\u3092\u4e8c\u4e57\u3057\u3066\u5e73\u5747\u3057\u307e\u3059\u3002\u3053\u308c\u304c\u5e73\u5747\u4e8c\u4e57\u96fb\u5727\u3067\u3001\u5358\u4f4d\u306fV\u00b2\u3067\u3059\u3002\u305d\u306e\u5e73\u65b9\u6839\u3092\u53d6\u308b\u3068\u3001\u96fb\u5727\u3068\u540c\u3058\u5358\u4f4dV\u306e<strong>\u5b9f\u52b9\u5024\uff08RMS\uff09<\/strong>\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\u71b1\u5e73\u8861\u306b\u3042\u308a\u3001\u5bfe\u8c61\u306e\u5468\u6ce2\u6570\u3067\u7d14\u7c8b\u306a\u62b5\u6297R\u3068\u3057\u3066\u6271\u3048\u308b\u90e8\u54c1\u306b\u3064\u3044\u3066\u3001\u53e4\u5178\u7684\u306a\u71b1\u96d1\u97f3\u306e\u5f0f\u306f\u6b21\u306e\u3088\u3046\u306b\u66f8\u3051\u307e\u3059\u3002[1]<\/p>\n<p style=\"overflow-wrap:anywhere\"><strong>\u5e73\u5747\u4e8c\u4e57\u96fb\u5727 = 4k<sub>B<\/sub>TRB<br \/>\u5b9f\u52b9\u5024 v<sub>rms<\/sub> = \u221a(4k<sub>B<\/sub>TRB)<\/strong><\/p>\n<p>T\u306f\u7d76\u5bfe\u6e29\u5ea6\u3067\u5358\u4f4d\u306fK\uff08\u30b1\u30eb\u30d3\u30f3\uff09\u3001B\u306f\u53d6\u308a\u8fbc\u3080\u5e2f\u57df\u5e45\u3067\u5358\u4f4d\u306fHz\u3067\u3059\u3002k<sub>B<\/sub>\u306f\u30dc\u30eb\u30c4\u30de\u30f3\u5b9a\u6570\u3067\u3001\u3053\u3053\u3067\u306f\u73fe\u884cSI\u306e\u53b3\u5bc6\u306a\u50241.380649 \u00d7 10<sup>\u221223<\/sup> J\/K\u3092\u4f7f\u3044\u307e\u3059\u3002[2] \u6e29\u5ea6\u306b\u306f\u6442\u6c0f\u306e\u6570\u5b57\u3092\u305d\u306e\u307e\u307e\u5165\u308c\u307e\u305b\u3093\u3002\u4f8b\u3048\u3070300 K\u306f\u7d0426.85\u2103\u3067\u3059\u3002<\/p>\n<p>\u3053\u306e\u5f0f\u306e\u96fb\u5727\u306f\u3001\u62b5\u6297\u306e\u4e21\u7aef\u3092\u8ca0\u8377\u306e\u5f71\u97ff\u306a\u3057\u306b\u89b3\u6e2c\u3059\u308b\u5834\u5408\u306e\u5024\u3067\u3059\u3002B\u306e\u7bc4\u56f2\u3092\u4e00\u5b9a\u306e\u5229\u5f971\u3067\u901a\u3057\u3001\u305d\u308c\u4ee5\u5916\u3092\u901a\u3055\u306a\u3044\u7406\u60f3\u7684\u306a\u30d5\u30a3\u30eb\u30bf\u30fc\u3092\u8003\u3048\u307e\u3059\u3002\u62b5\u6297\u3092\u5225\u306e\u56de\u8def\u306b\u3064\u306a\u3050\u3068\u5206\u5727\u3084\u5468\u6ce2\u6570\u5fdc\u7b54\u304c\u5909\u308f\u308b\u305f\u3081\u3001\u305d\u306e\u56de\u8def\u306e\u51fa\u529b\u3078\u7121\u6761\u4ef6\u306b\u5f53\u3066\u306f\u3081\u308b\u3053\u3068\u306f\u3067\u304d\u307e\u305b\u3093\u3002<\/p>\n<h2>1k\u03a9\u306e\u62b5\u6297\u3092\u3001\u3069\u308c\u3060\u3051\u5e83\u3044\u5e2f\u57df\u3067\u898b\u308b\u304b<\/h2>\n<p>\u6e29\u5ea6300 K\u3001\u62b5\u62971 k\u03a9\u3092\u4f8b\u306b\u3057\u307e\u3059\u3002\u96d1\u97f3\u306e\u5e73\u5747\u4e8c\u4e57\u96fb\u5727\u304c\u5468\u6ce2\u65701 Hz\u5f53\u305f\u308a\u306b\u3069\u308c\u3060\u3051\u5206\u5e03\u3059\u308b\u304b\u3092\u8868\u3059\u91cf\u304c\u3001\u96fb\u5727\u96d1\u97f3\u306e<strong>\u30d1\u30ef\u30fc\u30b9\u30da\u30af\u30c8\u30eb\u5bc6\u5ea6<\/strong>\u3067\u3059\u3002\u6b63\u306e\u5468\u6ce2\u6570\u5074\u3060\u3051\u3067\u6570\u3048\u308b\u300c\u7247\u5074\u300d\u306e\u5b9a\u7fa9\u3067\u306f\u3001<code>S<sub>v<\/sub> = 4k<sub>B<\/sub>TR<\/code>\u3001\u5358\u4f4d\u306fV\u00b2\/Hz\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\u305d\u306e\u5e73\u65b9\u6839\u306f\u7d04<strong>4.07 nV\/\u221aHz<\/strong>\u3067\u3059\u3002nV\u306f\u30ca\u30ce\u30dc\u30eb\u30c8\u300110\u5104\u5206\u306e1\u30dc\u30eb\u30c8\u3067\u3059\u3002\u3053\u308c\u306f\u300c\u3059\u3067\u306b\u6e2c\u5b9a\u3057\u305f\u96d1\u97f3\u96fb\u5727\u300d\u3067\u306f\u306a\u304f\u3001\u5e2f\u57df\u306b\u5bfe\u3059\u308b\u5bc6\u5ea6\u3067\u3059\u3002\u5b9f\u52b9\u5024\u3092\u6c42\u3081\u308b\u306b\u306f\u3001\u5e2f\u57df\u5e45\u306e\u5e73\u65b9\u6839\u3092\u639b\u3051\u307e\u3059\u3002Hz\u305d\u306e\u3082\u306e\u3092\u639b\u3051\u308b\u3068\u3001\u5358\u4f4d\u3082\u6570\u5024\u3082\u5408\u3044\u307e\u305b\u3093\u3002<\/p>\n<div style=\"max-width:100%;overflow-x:auto\">\n<table>\n<caption>300 K\u30fb1 k\u03a9\u3001\u7406\u60f3\u7684\u306a\u77e9\u5f62\u306e\u901a\u904e\u5e2f\u57df\u306b\u3088\u308b\u72ec\u81ea\u8a08\u7b97<\/caption>\n<thead>\n<tr>\n<th style=\"padding:10px;border:1px solid #cbd5df\">\u5e2f\u57df\u5e45B<\/th>\n<th style=\"padding:10px;border:1px solid #cbd5df\">\u96d1\u97f3\u96fb\u5727\u306e\u5b9f\u52b9\u5024<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"padding:10px;border:1px solid #cbd5df\">100 Hz<\/td>\n<td style=\"padding:10px;border:1px solid #cbd5df\">\u7d0440.7 nV<\/td>\n<\/tr>\n<tr>\n<td style=\"padding:10px;border:1px solid #cbd5df\">1 kHz<\/td>\n<td style=\"padding:10px;border:1px solid #cbd5df\">\u7d04128.7 nV<\/td>\n<\/tr>\n<tr>\n<td style=\"padding:10px;border:1px solid #cbd5df\">10 kHz<\/td>\n<td style=\"padding:10px;border:1px solid #cbd5df\">\u7d04407 nV<\/td>\n<\/tr>\n<tr>\n<td style=\"padding:10px;border:1px solid #cbd5df\">100 kHz<\/td>\n<td style=\"padding:10px;border:1px solid #cbd5df\">\u7d041.287 \u00b5V<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>1 kHz\u304b\u3089100 kHz\u3078\u5e83\u3052\u308b\u3068\u5e2f\u57df\u306f100\u500d\u3067\u3059\u304c\u3001\u5b9f\u52b9\u5024\u306f10\u500d\u3067\u3059\u3002\u52a0\u308f\u308b\u306e\u306f\u96fb\u5727\u306e\u5927\u304d\u3055\u305d\u306e\u3082\u306e\u3067\u306f\u306a\u304f\u3001\u307e\u305a\u5e73\u5747\u4e8c\u4e57\u306e\u91cf\u3060\u304b\u3089\u3067\u3059\u3002\u540c\u69d8\u306b\u3001\u5e2f\u57df\u3068\u6e29\u5ea6\u3092\u56fa\u5b9a\u3057\u305f\u307e\u307e\u62b5\u6297\u30924\u500d\u306b\u3059\u308b\u3068\u3001\u5b9f\u52b9\u5024\u306f2\u500d\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\u307e\u305f\u3001128.7 nV\u3068\u3044\u3046\u5b9f\u52b9\u5024\u306f\u300c\u77ac\u9593\u306e\u96fb\u5727\u304c\u5fc5\u305a\u3053\u306e\u7bc4\u56f2\u306b\u53ce\u307e\u308b\u300d\u3068\u3044\u3046\u4e0a\u9650\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u30e9\u30f3\u30c0\u30e0\u306a\u63fa\u3089\u304e\u3092\u7d71\u8a08\u7684\u306b\u8868\u3059\u5c3a\u5ea6\u3067\u3059\u3002\u30aa\u30b7\u30ed\u30b9\u30b3\u30fc\u30d7\u3067\u898b\u305f\u6700\u5927\u5024\u3084\u3001\u6e2c\u5b9a\u6642\u9593\u306e\u7570\u306a\u308b\u30d4\u30fc\u30af\u30fb\u30c4\u30fc\u30fb\u30d4\u30fc\u30af\u5024\u3068\u3001\u305d\u306e\u307e\u307e\u6bd4\u8f03\u3057\u306a\u3044\u3088\u3046\u306b\u3057\u307e\u3059\u3002<\/p>\n<h2>\u906e\u65ad\u5468\u6ce2\u65701kHz\u3067\u3082\u3001\u96d1\u97f3\u5e2f\u57df\u306f1kHz\u3068\u306f\u9650\u3089\u306a\u3044<\/h2>\n<p>\u73fe\u5b9f\u306e\u30ed\u30fc\u30d1\u30b9\u30d5\u30a3\u30eb\u30bf\u30fc\u306f\u3001\u5883\u754c\u3067\u6025\u306b\u3059\u3079\u3066\u3092\u906e\u308b\u308f\u3051\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u4e00\u6bb5\u306e\u7406\u60f3\u7684\u306aRC\u30ed\u30fc\u30d1\u30b9\u30d5\u30a3\u30eb\u30bf\u30fc\u3092\u8003\u3048\u3001\u4f4e\u3044\u5468\u6ce2\u6570\u3067\u306e\u96fb\u5727\u5229\u5f97\u30921\u3001\u906e\u65ad\u5468\u6ce2\u6570\u3092f<sub>c<\/sub>\u3068\u3057\u307e\u3059\u3002\u5468\u6ce2\u6570f\u3067\u306e\u96fb\u5727\u5229\u5f97H\u306e\u4e8c\u4e57\u306f\u3001\u6b21\u306e\u5f62\u3067\u3059\u3002<\/p>\n<p style=\"overflow-wrap:anywhere\"><strong>|H(f)|\u00b2 = 1 \/ {1 + (f\/f<sub>c<\/sub>)\u00b2}<\/strong><\/p>\n<p>f = f<sub>c<\/sub>\u3067\u306f\u5229\u5f97\u306e\u4e8c\u4e57\u304c1\/2\u3067\u3059\u3002\u3053\u3053\u304c\u901a\u5e38\u3044\u3046\u22123 dB\u306e\u906e\u65ad\u5468\u6ce2\u6570\u3067\u3042\u308a\u3001\u96d1\u97f3\u304c\u305d\u3053\u304b\u3089\u5148\u3078\u5168\u304f\u901a\u3089\u306a\u304f\u306a\u308b\u5730\u70b9\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<figure><img decoding=\"async\" src=\"https:\/\/quantumsea.net\/wp-content\/uploads\/2026\/10\/qs-johnson-noise-bandwidth-20261024-figure-b87bae7ce50f.png\" alt=\"\u906e\u65ad\u5468\u6ce2\u65701\u30ad\u30ed\u30d8\u30eb\u30c4\u306e\u4e00\u6b21\u30ed\u30fc\u30d1\u30b9\u306e\u5229\u5f97\u4e8c\u4e57\u306f\u3001\u305d\u308c\u3088\u308a\u9ad8\u3044\u5468\u6ce2\u6570\u3067\u3082\u30bc\u30ed\u306b\u306a\u3089\u306a\u3044\u3002\u7b49\u4fa1\u96d1\u97f3\u5e2f\u57df\u5e45\u306f1.571\u30ad\u30ed\u30d8\u30eb\u30c4\u3067\u3001\u5e451\u30ad\u30ed\u30d8\u30eb\u30c4\u306e\u77e9\u5f62\u3088\u308a\u5e83\u3044\u3002\" style=\"width:100%;height:auto;max-width:100%\"\/><figcaption>\u5229\u5f97\u306e\u4e8c\u4e57\u3092\u7a4d\u5206\u3059\u308b\u72ec\u81ea\u8a08\u7b97\u3002\u77e9\u5f62\u30d5\u30a3\u30eb\u30bf\u30fc\u306f1 kHz\u3067\u5b8c\u5168\u306b\u906e\u65ad\u3057\u307e\u3059\u304c\u3001\u4e00\u6b21\u30ed\u30fc\u30d1\u30b9\u306b\u306f\u9ad8\u3044\u5468\u6ce2\u6570\u5074\u306e\u88fe\u304c\u6b8b\u308a\u307e\u3059\u3002\u66f2\u7dda\u4e0b\u306e\u5168\u9762\u7a4d\u306b\u76f8\u5f53\u3059\u308b\u5e2f\u57df\u5e45\u306f\u7d041.571 kHz\u3067\u3059\u3002\u56f3\u306e\u6a2a\u8ef8\u3088\u308a\u5148\u306b\u3082\u88fe\u306f\u7d9a\u304d\u307e\u3059\u3002<\/figcaption><\/figure>\n<p>\u5165\u529b\u306e\u96d1\u97f3\u5bc6\u5ea6\u304c\u4e00\u5b9a\u306a\u3089\u3001\u51fa\u529b\u306e\u5e73\u5747\u4e8c\u4e57\u96fb\u5727\u306f\u3001\u5404\u5468\u6ce2\u6570\u3067\u901a\u904e\u3059\u308b\u5272\u5408\u3092\u8db3\u3057\u5408\u308f\u305b\u3066\u6c42\u3081\u3089\u308c\u307e\u3059\u3002\u3053\u3053\u3067\u306f\u6b63\u306e\u5468\u6ce2\u6570\u5168\u4f53\u306b\u3064\u3044\u3066\u7a4d\u5206\u3057\u307e\u3059\u3002<\/p>\n<p style=\"overflow-wrap:anywhere\"><strong>v<sub>rms<\/sub>\u00b2 = 4k<sub>B<\/sub>TR \u222b<sub>0<\/sub><sup>\u221e<\/sup>|H(f)|\u00b2 df<\/strong><\/p>\n<p>\u3053\u306e\u7a4d\u5206\u3092<strong>\u7b49\u4fa1\u96d1\u97f3\u5e2f\u57df\u5e45<\/strong>\u3068\u547c\u3073\u307e\u3059\u3002\u4f4e\u5468\u6ce2\u5229\u5f971\u3068\u3044\u3046\u4eca\u56de\u306e\u6761\u4ef6\u3067\u306f\u3001\u540c\u3058\u5e73\u5747\u4e8c\u4e57\u96d1\u97f3\u3092\u901a\u3059\u77e9\u5f62\u30d5\u30a3\u30eb\u30bf\u30fc\u306e\u5e45\u306b\u76f8\u5f53\u3057\u307e\u3059\u3002\u4e00\u6b21\u30ed\u30fc\u30d1\u30b9\u306e\u5f0f\u3078\u4ee3\u5165\u3059\u308b\u3068\u3001\u5909\u6570\u3092x = f\/f<sub>c<\/sub>\u306b\u7f6e\u304d\u63db\u3048\u3001<code>f<sub>c<\/sub>\u222b\u2080\u221e dx\/(1+x\u00b2) = \u03c0f<sub>c<\/sub>\/2<\/code>\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\u906e\u65ad\u5468\u6ce2\u6570\u304c1 kHz\u306a\u3089\u3001\u7b49\u4fa1\u96d1\u97f3\u5e2f\u57df\u5e45\u306f\u7d041.571 kHz\u3002\u5148\u307b\u3069\u3068\u540c\u3058300 K\u30fb1 k\u03a9\u3067\u306f\u3001\u5b9f\u52b9\u5024\u306f\u7d04<strong>161.3 nV<\/strong>\u3067\u3059\u3002\u77e9\u5f62\u306e1 kHz\u3067\u8a08\u7b97\u3057\u305f128.7 nV\u3088\u308a\u7d0425.3%\u5927\u304d\u304f\u306a\u308a\u307e\u3059\u3002\u906e\u65ad\u5468\u6ce2\u6570\u3060\u3051\u3092\u5e2f\u57df\u5e45\u306e\u6b04\u3078\u5165\u308c\u308b\u3068\u3001\u3053\u306e\u88fe\u306e\u5206\u3092\u843d\u3068\u3057\u3066\u3057\u307e\u3044\u307e\u3059\u3002<\/p>\n<h2>\u62b5\u6297\u3092\u5909\u3048\u308b\u3068\u304d\u306f\u3001\u5e2f\u57df\u3082\u5909\u308f\u3063\u3066\u3044\u306a\u3044\u304b\u3092\u898b\u308b<\/h2>\n<p>\u300c\u62b5\u6297\u30924\u500d\u306b\u3059\u308b\u3068\u96d1\u97f3\u96fb\u5727\u304c2\u500d\u300d\u3068\u3044\u3046\u5148\u307b\u3069\u306e\u6bd4\u8f03\u306b\u306f\u3001\u5e2f\u57df\u3092\u56fa\u5b9a\u3059\u308b\u6761\u4ef6\u304c\u3042\u308a\u307e\u3057\u305f\u3002\u3068\u3053\u308d\u304c\u3001\u305d\u306e\u62b5\u6297\u81ea\u8eab\u304cRC\u30d5\u30a3\u30eb\u30bf\u30fc\u3092\u69cb\u6210\u3059\u308b\u5834\u5408\u3001\u62b5\u6297\u3092\u5909\u3048\u308b\u3068\u906e\u65ad\u5468\u6ce2\u6570\u3082\u5909\u308f\u308a\u307e\u3059\u3002<\/p>\n<p>\u4e00\u3064\u306e\u62b5\u6297R\u3068\u30b3\u30f3\u30c7\u30f3\u30b5C\u3067\u3067\u304d\u305f\u3001\u8ca0\u8377\u306e\u306a\u3044\u7406\u60f3RC\u56de\u8def\u3067\u306f\u3001<code>f<sub>c<\/sub> = 1\/(2\u03c0RC)<\/code>\u3067\u3059\u3002\u3053\u306e\u5f0f\u3068\u7b49\u4fa1\u96d1\u97f3\u5e2f\u57df\u5e45\u3092\u7d44\u307f\u5408\u308f\u305b\u308b\u3068\u3001\u30b3\u30f3\u30c7\u30f3\u30b5\u4e21\u7aef\u306e\u5e73\u5747\u4e8c\u4e57\u71b1\u96d1\u97f3\u306f <strong>4k<sub>B<\/sub>TR \u00d7 \u03c0f<sub>c<\/sub>\/2 = k<sub>B<\/sub>T\/C<\/strong> \u3068\u306a\u308a\u307e\u3059\u3002\u3053\u308c\u306f\u540c\u3058\u53e4\u5178\u7684\u306a\u5e73\u8861\u30e2\u30c7\u30eb\u304b\u3089\u306e\u8a08\u7b97\u3067\u3059\u3002<\/p>\n<p>\u4f8b\u3048\u3070R\u304c1 k\u03a9\u3001C\u304c\u7d04159.2 nF\u306a\u3089\u906e\u65ad\u5468\u6ce2\u6570\u306f\u7d041 kHz\u3067\u3001\u96d1\u97f3\u306f\u7d04161.3 nV\u3067\u3059\u3002\u540c\u3058C\u306e\u307e\u307eR\u3092100 k\u03a9\u3078\u5897\u3084\u3059\u3068\u3001\u906e\u65ad\u5468\u6ce2\u6570\u306f\u7d0410 Hz\u306b\u306a\u308a\u307e\u3059\u3002\u62b5\u6297\u306e\u96d1\u97f3\u5bc6\u5ea6\u306f\u5927\u304d\u304f\u306a\u308a\u307e\u3059\u304c\u3001\u901a\u3059\u5e2f\u57df\u304c\u72ed\u304f\u306a\u308b\u305f\u3081\u3001\u3053\u306e\u30e2\u30c7\u30eb\u3067\u7a4d\u5206\u3057\u305f\u96d1\u97f3\u306e\u5b9f\u52b9\u5024\u306f\u5909\u308f\u308a\u307e\u305b\u3093\u3002\u305d\u306e\u4ee3\u308f\u308a\u3001\u56de\u8def\u304c\u5909\u5316\u306b\u8ffd\u3044\u3064\u304f\u6642\u9593\u306f100\u500d\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\u3053\u308c\u306f\u3001\u3069\u3093\u306a\u56de\u8def\u3067\u3082\u62b5\u6297\u5024\u3092\u7121\u8996\u3057\u3066\u3088\u3044\u3068\u3044\u3046\u610f\u5473\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u4e00\u5b9a\u306e\u5e2f\u57df\u3067\u62b5\u6297\u5358\u4f53\u3092\u6bd4\u3079\u308b\u306e\u304b\u3001\u540c\u3058\u5bb9\u91cf\u3092\u6301\u3064RC\u56de\u8def\u306e\u51fa\u529b\u3092\u6bd4\u3079\u308b\u306e\u304b\u3002\u56fa\u5b9a\u3059\u308b\u6761\u4ef6\u3092\u5148\u306b\u6c7a\u3081\u308b\u3068\u3001\u898b\u304b\u3051\u4e0a\u9055\u3046\u7d50\u8ad6\u3092\u6574\u7406\u3067\u304d\u307e\u3059\u3002<\/p>\n<h2>\u6e2c\u5b9a\u5e2f\u57df\u3092\u7d5e\u308b\u524d\u306b\u3001\u6b8b\u3057\u305f\u3044\u5909\u5316\u3092\u6c7a\u3081\u308b<\/h2>\n<p>\u3086\u3063\u304f\u308a\u5909\u308f\u308b\u30bb\u30f3\u30b5\u30fc\u306e\u5024\u3092\u8aad\u3080\u306a\u3089\u3001\u4e0d\u8981\u306a\u9ad8\u5468\u6ce2\u6210\u5206\u3092\u901a\u3055\u306a\u3044\u3053\u3068\u3067\u3001\u71b1\u96d1\u97f3\u306e\u5b9f\u52b9\u5024\u3092\u5c0f\u3055\u304f\u3067\u304d\u307e\u3059\u3002\u4e00\u65b9\u3001\u77ed\u3044\u30d1\u30eb\u30b9\u3084\u6025\u306a\u5909\u5316\u3092\u898b\u305f\u3044\u3068\u304d\u306b\u5e2f\u57df\u3092\u72ed\u3081\u3059\u304e\u308b\u3068\u3001\u76ee\u7684\u306e\u4fe1\u53f7\u307e\u3067\u4e38\u304f\u306a\u308a\u3001\u5fdc\u7b54\u3082\u9045\u308c\u307e\u3059\u3002\u96d1\u97f3\u306e\u6570\u5b57\u3060\u3051\u3092\u6700\u5c0f\u306b\u3059\u308b\u306e\u3067\u306f\u306a\u304f\u3001\u5fc5\u8981\u306a\u4fe1\u53f7\u306e\u5468\u6ce2\u6570\u3068\u5f85\u3066\u308b\u6642\u9593\u3092\u5408\u308f\u305b\u3066\u6c7a\u3081\u307e\u3059\u3002<\/p>\n<p>\u3053\u3053\u307e\u3067\u306e\u6570\u5024\u306f\u90e8\u54c1\u3084\u6e2c\u5b9a\u5668\u306e\u5b9f\u6e2c\u5024\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u71b1\u5e73\u8861\u3001\u4e00\u5b9a\u306e\u62b5\u6297\u5024\u3001\u8ca0\u8377\u306e\u5f71\u97ff\u3092\u9664\u3044\u305f\u7dda\u5f62\u56de\u8def\u3001\u305d\u3057\u3066\u91cf\u5b50\u52b9\u679c\u3092\u7121\u8996\u3067\u304d\u308b\u5468\u6ce2\u6570\u7bc4\u56f2\u3092\u4eee\u5b9a\u3057\u3066\u3044\u307e\u3059\u3002\u9ad8\u5468\u6ce2\u3067\u306f\u3001\u5149\u5b50\u306e\u30a8\u30cd\u30eb\u30ae\u30fchf\u304c\u71b1\u306e\u5c3a\u5ea6k<sub>B<\/sub>T\u306b\u6bd4\u3079\u3066\u5341\u5206\u5c0f\u3055\u3044\u304b\u3068\u3044\u3046\u6761\u4ef6\u306b\u3082\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n<p>\u5b9f\u6a5f\u3067\u306f\u5897\u5e45\u5668\u306e\u96fb\u5727\u30fb\u96fb\u6d41\u96d1\u97f3\u3001\u4f4e\u5468\u6ce2\u3067\u5897\u3048\u308b1\/f\u96d1\u97f3\u3001\u96fb\u6e90\u3084\u5916\u6765\u96fb\u6ce2\u306e\u6df7\u5165\u3001\u90e8\u54c1\u306e\u5bc4\u751f\u6210\u5206\u3082\u95a2\u308f\u308a\u307e\u3059\u3002\u62b5\u6297\u306e\u71b1\u96d1\u97f3\u306e\u8a08\u7b97\u3060\u3051\u3067\u3001\u6e2c\u5b9a\u7cfb\u5168\u4f53\u306e\u63fa\u3089\u304e\u3092\u8aac\u660e\u3057\u305f\u3053\u3068\u306b\u306f\u306a\u308a\u307e\u305b\u3093\u3002\u307e\u305a\u5bc6\u5ea6\u3068\u5b9f\u52b9\u5024\u3092\u5206\u3051\u3001\u6b21\u306b\u5b9f\u969b\u306e\u30d5\u30a3\u30eb\u30bf\u30fc\u306e\u5f62\u3068\u8ca0\u8377\u3092\u542b\u3081\u308b\u3002\u305d\u306e\u9806\u756a\u3067\u898b\u308b\u3068\u3001\u5e2f\u57df\u3092\u5e83\u3052\u3066\u5897\u3048\u305f\u63fa\u3089\u304e\u304c\u3001\u3069\u3053\u307e\u3067\u4e88\u60f3\u3067\u304d\u308b\u304b\u3092\u5224\u65ad\u3057\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n<h2>\u51fa\u5178<\/h2>\n<ol>\n<li>Albert J. Williams 3rd, <a href=\"https:\/\/ocw.mit.edu\/courses\/2-693-principles-of-oceanographic-instrument-systems-sensors-and-measurements-13-998-spring-2004\/9752c8f35620ae8f5dea0992f2805a1e_notes_williams.pdf\">Principles of Oceanographic Instrument Systems: Sensors and Measurements<\/a>, MIT OpenCourseWare\u30011983\u5e741\u6708\u4f5c\u6210\u30fb2004\u5e742\u6708\u6539\u8a02\u30016\u301c7\u30da\u30fc\u30b8\u3002\u62b5\u6297\u306e\u71b1\u96d1\u97f3\u3068\u5e2f\u57df\u5e45\u306e\u95a2\u4fc2\u3092\u53c2\u7167\u3002\u30d5\u30a3\u30eb\u30bf\u30fc\u7a4d\u5206\u3001\u8868\u3068\u56f3\u306e\u6570\u5024\u306f\u672c\u7a3f\u306e\u6761\u4ef6\u306b\u3088\u308b\u72ec\u81ea\u8a08\u7b97\u3067\u3059\u3002<\/li>\n<li>NIST, <a href=\"https:\/\/www.nist.gov\/si-redefinition\/kelvin\/kelvin-boltzmann-constant\">Kelvin: Boltzmann Constant<\/a>\u30012026\u5e745\u670828\u65e5\u66f4\u65b0\u3002\u73fe\u884cSI\u306e\u30dc\u30eb\u30c4\u30de\u30f3\u5b9a\u6570\u306e\u5024\u3068\u5b9a\u7fa9\u3092\u53c2\u7167\u3002<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>\u30bb\u30f3\u30b5\u30fc\u306e\u5c0f\u3055\u306a\u96fb\u5727\u3092\u6e2c\u308b\u3068\u304d\u3001\u6e2c\u5b9a\u5668\u306e\u5e2f\u57df\u5e45\u3092\u5e83\u3052\u308b\u3068\u3001\u4fe1\u53f7\u306e\u901f\u3044\u5909\u5316\u3092\u8ffd\u3044\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002\u3057\u304b\u3057\u3001\u8868\u793a\u306e\u63fa\u3089\u304e\u307e\u3067\u5927\u304d\u304f\u306a\u308b\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u3002\u5468\u6ce2\u6570\u306e\u5e83\u3044\u7bc4\u56f2\u306b\u5206\u5e03\u3059\u308b\u96d1\u97f3\u3082\u3001\u4e00\u7dd2\u306b\u53d6\u308a\u8fbc\u3080\u305f\u3081\u3067\u3059\u3002 \u305d\u306e\u57fa\u672c\u7684\u306a\u4e00\u3064 [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":1512,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":true,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":false,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[32],"tags":[303],"class_list":["post-1514","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-semiconductors-electronics","tag-johnson-noise"],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/quantumsea.net\/wp-content\/uploads\/2026\/10\/qs-johnson-noise-bandwidth-20261024-featured-8262dd552bfd.png","_links":{"self":[{"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/posts\/1514","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1514"}],"version-history":[{"count":2,"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/posts\/1514\/revisions"}],"predecessor-version":[{"id":1788,"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/posts\/1514\/revisions\/1788"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/media\/1512"}],"wp:attachment":[{"href":"https:\/\/quantumsea.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1514"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1514"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1514"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}