dbm和db与W之间的关系 dB和dBm又有什么区别？
dBm\u548cdB\u7684\u5173\u7cfb\u662f\u4ec0\u4e48\uff1fdB\u7684\u5f15\u5165\u662f\u4e3a\u4e86\u628a\u4e58\u9664\u5173\u7cfb\u53d8\u6362\u4e3a\u52a0\u51cf\uff0c\u4fbf\u4e8e\u5de5\u7a0b\u4e2d\u7684\u8fd0\u7b97\u3002[dB] = 10lg(\u8f93\u51fa\u529f\u7387W/\u8f93\u5165\u529f\u7387W)\u3002\u5982\uff1a\u8f93\u5165\u529f\u7387\u4e3a1W\u800c\u8f93\u51fa\u7387\u4e3a1000W\uff0c\u5219\u7cfb\u7edf\u7684\u589e\u76ca\u4e3a10lg(1000/1)=30dB\u3002
\u901a\u4fe1\u4e2d\u4e3a\u4e86\u8868\u793a\u4e00\u4e2a\u8f93\u51fa\u529f\u7387\u7684\u7edd\u5bf9\u503c\uff0c\u5219\u5f15\u5165\u4e86dBm\u3002
dBm\u8868\u793a\u76f8\u5bf9\u4e8e1mW\u8f93\u5165\u529f\u7387\u7684\u7cfb\u7edf\u589e\u76ca\uff08\u5bf9\u4e8e1mW\u7684\u653e\u5927\u500d\u6570\uff09\u3002\u5982\u679c\u7cfb\u7edf\u7684\u8f93\u51fa\u529f\u7387\u4e3a1W\uff0c\u6362\u7b97\u4e3adBm\u5219\u4e3a\uff1adBm=10lg(1W/1mW) = 10lg(1000) = 30 dBm\u3002
\u5206\u8d1d
\u5206\u8d1d\uff08decibel\uff09\u662f\u91cf\u5ea6\u4e24\u4e2a\u76f8\u540c\u5355\u4f4d\u4e4b\u6570\u91cf\u6bd4\u4f8b\u7684\u5355\u4f4d\uff0c\u4e3b\u8981\u7528\u4e8e\u5ea6\u91cf\u58f0\u97f3\u5f3a\u5ea6\uff0c\u5e38\u7528dB\u8868\u793a\u3002\u201c\u5206\u201d\uff08deci-\uff09\u6307\u5341\u5206\u4e4b\u4e00\uff0c\u4e2a\u4f4d\u662f\u201c\u8d1d\u201d\u6216\u201c\u8d1d\u5c14\u201d\uff08bel\uff0c\u7eaa\u5ff5\u53d1\u660e\u5bb6\u4e9a\u5386\u5c71\u5927\u00b7\u683c\u62c9\u6c49\u59c6\u00b7\u8d1d\u5c14\uff09\uff0c\u4f46\u4e00\u822c\u53ea\u7528\u5206\u8d1d\u3002
\u901a\u5e38\u88ab\u8ba4\u4e3a\u662f\u4eba\u7c7b\u7684\u6700\u5c11\u542c\u89c9\u54cd\u5e94\u503c\uff08\u5927\u7ea6\u662f3\u7c73\u4ee5\u5916\u98de\u884c\u7684\u868a\u5b50\u58f0\u97f3\uff09\u3002\u6700\u5b8c\u5584\u7684\u6c34\u5e73\u6d4b\u91cf\uff0c\u6d4b\u91cf1\u5e15\u65af\u5361\u7b49\u4e8e94\u5206\u8d1d\u58f0\u538b\u7ea7\u3002\u5728\u5176\u4ed6\u4ecb\u8d28\uff0c\u5982\u6c34\u4e0b\uff0c1\u5fae\u5e15\u65af\u5361\u66f4\u4e3a\u666e\u904d\u3002\u8fd9\u4e9b\u6807\u51c6\u88abANSIS1.1-1994.\u6240\u6536\u5f55\u3002
\u4ee5\u4e0a\u5185\u5bb9\u53c2\u8003\uff1a\u767e\u5ea6\u767e\u79d1-dBm
\u9996\u5148\uff0c DB \u662f\u4e00\u4e2a\u7eaf\u8ba1\u6570\u5355\u4f4d\uff1adB = 10logX\u3002dB\u7684\u610f\u4e49\u5176\u5b9e\u518d\u7b80\u5355\u4e0d\u8fc7\u4e86\uff0c\u5c31\u662f\u628a\u4e00\u4e2a\u5f88\u5927\uff08\u540e\u9762\u8ddf\u4e00\u957f\u4e320\u7684\uff09\u6216\u8005\u5f88\u5c0f\uff08\u524d\u9762\u6709\u4e00\u957f\u4e320\u7684\uff09\u7684\u6570\u6bd4\u8f83\u7b80\u77ed\u5730\u8868\u793a\u51fa\u6765\u3002\u5982\uff1a
X = 1000000000000000\uff08\u591a\u5c11\u4e2a\u4e86\uff1f\uff09= 10logX = 150 dB
X = 0.000000000000001 = 10logX = -150 dB
dBm \u5b9a\u4e49\u7684\u662f miliwatt\u3002 0 dBm = 10log1 mw\uff1b
dBw \u5b9a\u4e49 watt\u3002 0 dBw = 10log1 W = 10log1000 mw = 30 dBm\u3002
DB\u5728\u7f3a\u7701\u60c5\u51b5\u4e0b\u603b\u662f\u5b9a\u4e49\u529f\u7387\u5355\u4f4d\uff0c\u4ee5 10log \u4e3a\u8ba1\u3002\u5f53\u7136\u67d0\u4e9b\u60c5\u51b5\u4e0b\u53ef\u4ee5\u7528\u4fe1\u53f7\u5f3a\u5ea6\uff08Amplitude\uff09\u6765\u63cf\u8ff0\u529f\u548c\u529f\u7387\uff0c\u8fd9\u65f6\u5019\u5c31\u7528 20log \u4e3a\u8ba1\u3002\u4e0d\u7ba1\u662f\u63a7\u5236\u9886\u57df\u8fd8\u662f\u4fe1\u53f7\u5904\u7406\u9886\u57df\u90fd\u662f\u8fd9\u6837\u3002\u6bd4\u5982\u6709\u65f6\u5019\u5927\u5bb6\u53ef\u4ee5\u770b\u5230 dBmV \u7684\u8868\u8fbe\u3002
\u5728dB\uff0cdBm\u8ba1\u7b97\u4e2d\uff0c\u8981\u6ce8\u610f\u57fa\u672c\u6982\u5ff5\u3002\u6bd4\u5982\u524d\u9762\u8bf4\u7684 0dBw = 10log1W = 10log1000mw = 30dBm\uff1b\u53c8\u6bd4\u5982\uff0c\u7528\u4e00\u4e2adBm \u51cf\u53e6\u5916\u4e00\u4e2adBm\u65f6\uff0c\u5f97\u5230\u7684\u7ed3\u679c\u662fdB\u3002\u5982\uff1a30dBm - 0dBm = 30dB\u3002
\u4e00\u822c\u6765\u8bb2\uff0c\u5728\u5de5\u7a0b\u4e2d\uff0cdB\u548cdB\u4e4b\u95f4\u53ea\u6709\u52a0\u51cf\uff0c\u6ca1\u6709\u4e58\u9664\u3002\u800c\u7528\u5f97\u6700\u591a\u7684\u662f\u51cf\u6cd5\uff1adBm \u51cf dBm \u5b9e\u9645\u4e0a\u662f\u4e24\u4e2a\u529f\u7387\u76f8\u9664\uff0c\u4fe1\u53f7\u529f\u7387\u548c\u566a\u58f0\u529f\u7387\u76f8\u9664\u5c31\u662f\u4fe1\u566a\u6bd4\uff08SNR\uff09\u3002dBm \u52a0 dBm \u5b9e\u9645\u4e0a\u662f\u4e24\u4e2a\u529f\u7387\u76f8\u4e58\uff0c\u8fd9\u4e2a\u5df2\u7ecf\u4e0d\u591a\u89c1\uff08\u6211\u53ea\u77e5\u9053\u5728\u529f\u7387\u8c31\u5377\u79ef\u8ba1\u7b97\u4e2d\u6709\u8fd9\u6837\u7684\u5e94\u7528\uff09\u3002dBm \u4e58 dBm \u662f\u4ec0\u4e48\uff0c1mW \u7684 1mW \u6b21\u65b9\uff1f\u9664\u4e86\u540c\u5b66\u4eec\u8001\u7ed9\u6211\u5199\u8fd9\u6837\u51e0\u4e4e\u53ef\u4ee5\u548c\u6b4c\u5fb7\u5df4\u8d6b\u731c\u60f3\u5e76\u9a7e\u9f50\u9a71\u7684\u8868\u8fbe\u5f0f\u5916\uff0c\u6211\u6d3b\u4e86\u8fd9\u4e48\u591a\u5e74\u4e5f\u6ca1\u89c1\u8fc7\u54ea\u4e2a\u5de5\u7a0b\u9886\u57df\u73a9\u8fd9\u4e2a\u3002
dB\u662f\u529f\u7387\u589e\u76ca\u7684\u5355\u4f4d\uff0c\u8868\u793a\u4e00\u4e2a\u76f8\u5bf9\u503c\u3002\u5f53\u8ba1\u7b97A\u7684\u529f\u7387\u76f8\u6bd4\u4e8eB\u5927\u6216\u5c0f\u591a\u5c11\u4e2adB\u65f6\uff0c\u53ef\u6309\u516c\u5f0f10 lg A/B\u8ba1\u7b97\u3002\u4f8b\u5982\uff1aA\u529f\u7387\u6bd4B\u529f\u7387\u5927\u4e00\u500d\uff0c\u90a3\u4e4810 lg A/B = 10 lg 2 = 3dB\u3002\u4e5f\u5c31\u662f\u8bf4\uff0cA\u7684\u529f\u7387\u6bd4B\u7684\u529f\u7387\u59273dB\uff1b\u5982\u679cA\u7684\u529f\u7387\u4e3a46dBm\uff0cB\u7684\u529f\u7387\u4e3a40dBm\uff0c\u5219\u53ef\u4ee5\u8bf4\uff0cA\u6bd4B\u59276dB\uff1b\u5982\u679cA\u5929\u7ebf\u4e3a12dBd\uff0cB\u5929\u7ebf\u4e3a14dBd\uff0c\u53ef\u4ee5\u8bf4A\u6bd4B\u5c0f2dB\u3002
dBm\u662f\u4e00\u4e2a\u8868\u793a\u529f\u7387\u7edd\u5bf9\u503c\u7684\u5355\u4f4d\uff0c\u8ba1\u7b97\u516c\u5f0f\u4e3a\uff1a10lg\u529f\u7387\u503c/1mW\u3002\u4f8b\u5982\uff1a\u5982\u679c\u53d1\u5c04\u529f\u7387\u4e3a1mW\uff0c\u6309dBm\u5355\u4f4d\u8fdb\u884c\u6298\u7b97\u540e\u7684\u503c\u5e94\u4e3a\uff1a10 lg 1mW/1mW = 0dBm\uff1b\u5bf9\u4e8e40W\u7684\u529f\u7387,\u521910 lg(40W/1mW)=46dBm\u3002
dBm和dBW
dBm是一个考征功率绝对值的值，是以1mW的功率做为参考，直接读作dBm或者dB毫
计算公式:10lg（毫瓦标示的实际功率/1mW）,
例如：0dBm=1mW，10dBm=10mW，17dBm=50mW，20dBm=100mW，27dBm=500mW，30dBm=1000mW。dBW则是以1W功率作为参考，此单位很少用。
绛旓細X=1000000000000000 锛堝叡15涓0锛夊彲浠ヨ〃绀轰负锛10lgX=150dB X=0.000000000000001 鍙互琛ㄧず涓猴細10lgX=-150 dB dBm 瀹氫箟鐨勬槸 miliwatt(姣摝鐗)銆0 dBm=1mw锛沝Bw 瀹氫箟 watt銆0 dBW = 1 W =1000 mw = 10lg(1000/1)dBm=30dbm銆俵gX鍦ㄧ己鐪"X"鎯呭喌涓嬫绘槸瀹氫箟鍔熺巼鍗曚綅锛屼互 10lg 涓鸿銆傚綋鐒舵煇浜涙儏鍐...
绛旓細0 dBm = 10log1 mw锛沝Bw 瀹氫箟 watt銆 0 dBw = 10log1 W = 10log1000 mw = 30 dBm銆 DB鍦ㄧ己鐪佹儏鍐典笅鎬绘槸瀹氫箟鍔熺巼鍗曚綅锛屼互 10log 涓鸿銆傚綋鐒舵煇浜涙儏鍐典笅鍙互鐢ㄤ俊鍙峰己搴︼紙Amplitude锛夋潵鎻忚堪鍔熷拰鍔熺巼锛岃繖鏃跺欏氨鐢 20log 涓鸿銆備笉绠℃槸鎺у埗棰嗗煙杩樻槸淇″彿澶勭悊棰嗗煙閮芥槸杩欐牱銆傛瘮濡傛湁鏃跺欏ぇ瀹跺彲浠ョ湅鍒 ...
绛旓細dBw 涓巇Bm涓鏍凤紝dBw鏄竴涓〃绀哄姛鐜囩粷瀵瑰肩殑鍗曚綅锛堜篃鍙互璁や负鏄互1W鍔熺巼涓哄熀鍑嗙殑涓涓瘮鍊硷級锛岃绠楀叕寮忎负锛10log锛堝姛鐜囧/1w锛夈dBw涓dBm涔嬮棿鐨鎹㈢畻鍏崇郴涓猴細0 dBw = 10log1 W = 10log1000 mw = 30 dBm銆俒渚媇 濡傛灉鍔熺巼P涓1w锛屾姌绠椾负dBw鍚庝负0dBw銆傛讳箣锛宒B锛宒Bi, dBd, dBc鏄袱涓噺涔嬮棿鐨...
绛旓細W 灏辨槸涓嶈浜嗗惂锛屽姛鐜嘝鐨勫崟浣 dBm 瀹氫箟鐨勬槸 miliwatt銆倅 dBm = 10log ( P /1 mw), 濡 0 dBm = 10log1 mw锛沝B 瀹氫箟鏄袱涓姛鐜囧樊 = 10log ( P2 / P1 ) 锛
绛旓細0dBm=1mW锛堟鐡︼級锛屾瘡澧炲姞3dB鍔熺巼澧炲姞涓鍊嶏紝3dBm=2mW銆6dBm=4mW...10dBm=10mW銆20dBm=100mW銆30dBm=1000mW...銆
绛旓細dB鏄痙ecibel鐨勭缉鍐欐剰鍗冲崄鍒嗕箣涓璐濆皵(bel)涓 鍒嗚礉銆傚垎璐(dB)鏄浗闄呬笂缁-浣跨敤鐨勭數淇′紶杈撳崟浣嶏紝瀹冩槸娌℃湁閲忕翰鐨勫鏁拌鏁板崟浣嶃傚湪鐢典俊鎶鏈鍩燂紝涓轰簡鍑嗙‘璁￠噺淇″彿鍦ㄧ數璺腑鍚勭偣鐨勫姛鐜囥佺數鍘嬪拰鐢垫祦绛夌殑浼犺緭鍙樺寲鎯呭喌锛屼竴鑸笉鐩存帴鐢ㄧ摝(W)銆佷紡()鍜屽畨(A)浣滀负娴嬮噺 銆傝绠楁柟娉 鍩虹鍏紡0dBm=1mW锛堝繀椤昏涓嬫潵锛...
绛旓細涓巇Bm涓鏍凤紝dBw鏄竴涓〃绀哄姛鐜囩粷瀵瑰肩殑鍗曚綅锛堜互1W鍔熺巼涓哄熀鍑嗭紝dBm鏄互1mW涓哄熀鍑嗭級銆dBw涓dBm涔嬮棿鐨鎹㈢畻鍏崇郴涓猴細0 dBw = 10log1 W = 10log1000 mw = 30 dBm銆俤B锛宒Bi, dBd, dBc鏄袱涓噺涔嬮棿鐨勬瘮鍊硷紝琛ㄧず涓や釜閲忛棿鐨勭浉瀵瑰ぇ灏忥紝鑰宒Bm銆乨Bw鍒欐槸琛ㄧず鍔熺巼缁濆澶у皬鐨勫笺傚湪dB锛宒Bm锛宒Bw璁＄畻涓紝...
绛旓細1銆db涓巇bm锛氱敤涓涓dBm鍑忓彟澶栦竴涓猟Bm鏃讹紝寰楀埌鐨勭粨鏋滄槸dB銆俤Bm鍑廳Bm瀹為檯涓婃槸涓や釜鍔熺巼鐩搁櫎锛屼俊鍙峰姛鐜囧拰鍣０鍔熺巼鐩搁櫎灏辨槸淇″櫔姣旓紙SNR锛夈傛瘮濡傦細30dBm - 0dBm = 1000mW/1mW = 1000 = 30dB銆俤Bm鏄竴涓〃绀哄姛鐜囩粷瀵瑰肩殑鍗曚綅锛岃绠楀叕寮忎负锛10lg鍔熺巼鍊/1mW銆2銆乨bd涓巇bi锛0dBd=2.15dBi銆俤Bi鐨勫弬鑰...
绛旓細杩欓噷鐨勫畾涔変负璇ユ埧闂寸殑鏈夌敤淇″彿寮哄害涓庢墍鏈変俊鍙凤紙鍖呮嫭骞叉壈淇″彿锛夌殑姣斿笺傚父瑙佽〃绀哄舰寮忥細dBm銆乨Bw 锛3锛夊湪澶╃嚎鎶鏈柟闈紝DB鏄 閲忓ぉ绾挎ц兘鐨勪竴涓弬鏁帮紝鍚嶇О涓哄鐩娿傚畠鏄寚鍦ㄨ緭鍏ュ姛鐜囩浉绛夌殑鏉′欢涓嬶紝瀹為檯澶╃嚎涓庣悊鎯冲ぉ绾垮湪绌洪棿鍚屼竴鐐瑰鎵浜х敓鐨勪俊鍙风殑鍔熺巼瀵嗗害涔嬫瘮銆傚父瑙佽〃绀哄舰寮忥細dBi銆乨Bd ...
绛旓細X = 1000000000000000锛堝灏戜釜浜嗭紵锛= 10logX = 150 dB X = 0.000000000000001 = 10logX = -150 dB dBm 瀹氫箟鐨勬槸 miliwatt銆 0 dBm = 10log1 mw锛沝Bw 瀹氫箟 watt銆 0 dBw = 10log1 W = 10log1000 mw = 30 dBm銆DB鍦ㄧ己鐪佹儏鍐典笅鎬绘槸瀹氫箟鍔熺巼鍗曚綅锛屼互 10log 涓鸿銆傚綋鐒舵煇浜涙儏鍐典笅鍙互...
