噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)監(jian)(jian)測(ce)(ce)是對煩擾我(wo)們學(xue)習(xi)、作業和(he)(he)日子的(de)(de)(de)聲(sheng)(sheng)(sheng)(sheng)(sheng)響及其聲(sheng)(sheng)(sheng)(sheng)(sheng)源(yuan)進行的(de)(de)(de)監(jian)(jian)測(ce)(ce)活動(dong)。其間包括：城市各功用區噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)監(jian)(jian)測(ce)(ce)、路途交(jiao)通噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)監(jian)(jian)測(ce)(ce)、區域環境噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)監(jian)(jian)測(ce)(ce)和(he)(he)噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)源(yuan)監(jian)(jian)測(ce)(ce)等。噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)監(jian)(jian)測(ce)(ce)成果析噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)污(wu)染(ran)(ran)的(de)(de)(de)現(xian)狀及改變趨勢，也(ye)為(wei)噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)污(wu)染(ran)(ran)的(de)(de)(de)方案辦理(li)和(he)(he)歸納(na)整治供給根底(di)數據。通常以A計(ji)權聲(sheng)(sheng)(sheng)(sheng)(sheng)級標(biao)明，所用的(de)(de)(de)首要儀器是聲(sheng)(sheng)(sheng)(sheng)(sheng)級計(ji)和(he)(he)頻譜分析器。噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)監(jian)(jian)測(ce)(ce)的(de)(de)(de)成果用于分析噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)污(wu)染(ran)(ran)的(de)(de)(de)現(xian)狀及改變趨勢，也(ye)為(wei)噪(zao)聲(sheng)(sheng)(sheng)(sheng)(sheng)污(wu)染(ran)(ran)的(de)(de)(de)方案辦理(li)和(he)(he)歸納(na)整治供給根底(di)數據。

    噪(zao)(zao)聲又稱雜音，歸于(yu)隨機(ji)信號，可用計算(suan)學辦法加以描繪，即其計算(suan)量是可測(ce)的。噪(zao)(zao)聲存在(zai)于(yu)悉數電子體系中(zhong)，嚴峻地(di)影(ying)(ying)響通(tong)訊(xun)體系接收微小信號的才能，即影(ying)(ying)響通(tong)訊(xun)的質量。

    噪聲(sheng)測量包括兩個(ge)內(nei)容：對噪聲(sheng)計算特性的測量和使用噪聲(sheng)作(zuo)為查驗信號的測量。

    計算特(te)(te)性(xing)的(de)(de)測(ce)量(liang)(liang)噪(zao)聲計算特(te)(te)性(xing)的(de)(de)測(ce)量(liang)(liang)歸(gui)于高低域測(ce)量(liang)(liang)，包括數學期(qi)望（均(jun)勻(yun)值(zhi)(zhi)），方差（均(jun)方值(zhi)(zhi)），功率譜密度、概率密度分布以及自有關和互有關函數的(de)(de)測(ce)量(liang)(liang)。通訊線路(lu)噪(zao)聲的(de)(de)測(ce)量(liang)(liang)，就是在規則(ze)帶寬內，噪(zao)聲均(jun)方值(zhi)(zhi)（功率）或均(jun)方根值(zhi)(zhi)（有用值(zhi)(zhi)）的(de)(de)測(ce)量(liang)(liang)。

    隨機信號(hao)(hao)電(dian)(dian)(dian)(dian)壓的(de)(de)測(ce)(ce)量與(yu)確(que)知信號(hao)(hao)電(dian)(dian)(dian)(dian)壓的(de)(de)測(ce)(ce)量不一樣：①有(you)(you)必(bi)要留心電(dian)(dian)(dian)(dian)壓表(biao)(biao)的(de)(de)檢波(bo)(bo)特性，有(you)(you)用(yong)值(zhi)電(dian)(dian)(dian)(dian)壓表(biao)(biao)是測(ce)(ce)量噪(zao)聲電(dian)(dian)(dian)(dian)壓比照抱負的(de)(de)表(biao)(biao)面，這(zhe)種(zhong)電(dian)(dian)(dian)(dian)壓表(biao)(biao)的(de)(de)讀數(shu)(shu)與(yu)被(bei)測(ce)(ce)電(dian)(dian)(dian)(dian)壓的(de)(de)均方根值(zhi)成(cheng)正比，與(yu)被(bei)測(ce)(ce)電(dian)(dian)(dian)(dian)壓的(de)(de)波(bo)(bo)形無關，故若該電(dian)(dian)(dian)(dian)壓表(biao)(biao)以正弦有(you)(you)用(yong)值(zhi)刻度，則可便利地直接讀出噪(zao)聲電(dian)(dian)(dian)(dian)壓的(de)(de)有(you)(you)用(yong)值(zhi)。否則，需要對讀數(shu)(shu)進行(xing)批改(gai)。例(li)如，選用(yong)均值(zhi)電(dian)(dian)(dian)(dian)壓表(biao)(biao)測(ce)(ce)量高斯白噪(zao)聲，有(you)(you)必(bi)要將讀數(shu)(shu)乘上批改(gai)因數(shu)(shu)1．13。

    ②帶寬(kuan)原則。噪聲(sheng)功(gong)率正比于體(ti)(ti)系的(de)(de)(de)帶寬(kuan)，選用的(de)(de)(de)電(dian)(dian)壓(ya)(ya)表其帶寬(kuan)應遠大于被(bei)測(ce)體(ti)(ti)系的(de)(de)(de)噪聲(sheng)帶寬(kuan)，否(fou)則，將會丟(diu)掉噪聲(sheng)功(gong)率，使測(ce)量(liang)成果偏低。通(tong)常需求電(dian)(dian)壓(ya)(ya)表的(de)(de)(de)3dB帶寬(kuan)△f3db大于8～10倍的(de)(de)(de)噪聲(sheng)帶寬(kuan)。

    ③滿(man)(man)度(du)(du)(du)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)峰(feng)(feng)(feng)(feng)(feng)因(yin)數(shu)和測(ce)量(liang)時(shi)刻的(de)(de)(de)(de)(de)(de)影響。波(bo)(bo)(bo)(bo)(bo)(bo)(bo)峰(feng)(feng)(feng)(feng)(feng)因(yin)數(shu)是交流電(dian)(dian)(dian)(dian)壓的(de)(de)(de)(de)(de)(de)峰(feng)(feng)(feng)(feng)(feng)值(zhi)與有(you)用(yong)值(zhi)之比，如正弦(xian)(xian)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)的(de)(de)(de)(de)(de)(de)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)峰(feng)(feng)(feng)(feng)(feng)因(yin)數(shu)為(wei)。以(yi)(yi)(yi)(yi)測(ce)量(liang)確(que)知(zhi)信號正弦(xian)(xian)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)為(wei)例，當有(you)用(yong)值(zhi)電(dian)(dian)(dian)(dian)壓表(biao)指示滿(man)(man)度(du)(du)(du)時(shi)，其(qi)寬帶(dai)擴(kuo)展(zhan)器(qi)所承受的(de)(de)(de)(de)(de)(de)大瞬時(shi)電(dian)(dian)(dian)(dian)壓（峰(feng)(feng)(feng)(feng)(feng)值(zhi)）為(wei)有(you)用(yong)值(zhi)的(de)(de)(de)(de)(de)(de)倍，若擴(kuo)展(zhan)器(qi)的(de)(de)(de)(de)(de)(de)動態規模滿(man)(man)足，不會發(fa)生測(ce)量(liang)過失(shi)。所以(yi)(yi)(yi)(yi)，對(dui)電(dian)(dian)(dian)(dian)壓表(biao)中運用(yong)的(de)(de)(de)(de)(de)(de)擴(kuo)展(zhan)器(qi)，可(ke)用(yong)其(qi)滿(man)(man)度(du)(du)(du)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)峰(feng)(feng)(feng)(feng)(feng)因(yin)數(shu)直接(jie)反映擴(kuo)展(zhan)器(qi)的(de)(de)(de)(de)(de)(de)動態規模般測(ce)量(liang)正弦(xian)(xian)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓表(biao)來(lai)說，需求電(dian)(dian)(dian)(dian)壓表(biao)具有(you)的(de)(de)(de)(de)(de)(de)滿(man)(man)度(du)(du)(du)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)峰(feng)(feng)(feng)(feng)(feng)因(yin)數(shu)就可(ke)擔任。因(yin)為(wei)噪(zao)(zao)聲(sheng)電(dian)(dian)(dian)(dian)壓的(de)(de)(de)(de)(de)(de)峰(feng)(feng)(feng)(feng)(feng)值(zhi)是隨機的(de)(de)(de)(de)(de)(de)，即(ji)其(qi)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)峰(feng)(feng)(feng)(feng)(feng)因(yin)數(shu)也是隨機的(de)(de)(de)(de)(de)(de)，所以(yi)(yi)(yi)(yi)，只(zhi)能用(yong)計算學辦法來(lai)定量(liang)描繪(hui)峰(feng)(feng)(feng)(feng)(feng)值(zhi)大于有(you)用(yong)值(zhi)的(de)(de)(de)(de)(de)(de)概(gai)(gai)(gai)率(lv)，以(yi)(yi)(yi)(yi)高斯白(bai)噪(zao)(zao)聲(sheng)為(wei)例，其(qi)峰(feng)(feng)(feng)(feng)(feng)值(zhi)是波(bo)(bo)(bo)(bo)(bo)(bo)(bo)峰(feng)(feng)(feng)(feng)(feng)因(yin)數(shu)大于4．4呈現(xian)的(de)(de)(de)(de)(de)(de)概(gai)(gai)(gai)率(lv)為(wei)0.001%。所以(yi)(yi)(yi)(yi)，若電(dian)(dian)(dian)(dian)壓表(biao)的(de)(de)(de)(de)(de)(de)滿(man)(man)度(du)(du)(du)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)峰(feng)(feng)(feng)(feng)(feng)因(yin)數(shu)大于4．4，那(nei)么(me)，用(yong)來(lai)測(ce)量(liang)高斯白(bai)噪(zao)(zao)聲(sheng)是滿(man)(man)足的(de)(de)(de)(de)(de)(de)，因(yin)為(wei)，這時(shi)電(dian)(dian)(dian)(dian)壓表(biao)只(zhi)對(dui)呈現(xian)概(gai)(gai)(gai)率(lv)小于0．001%的(de)(de)(de)(de)(de)(de)那(nei)些(xie)頂峰(feng)(feng)(feng)(feng)(feng)值(zhi)不予計及（被擴(kuo)展(zhan)器(qi)削(xue)波(bo)(bo)(bo)(bo)(bo)(bo)(bo)），分析指出，由此發(fa)生的(de)(de)(de)(de)(de)(de)測(ce)量(liang)過失(shi)為(wei)-0．05%。

    ④電(dian)話電(dian)路的(de)(de)噪聲測(ce)量(liang)，宜加衡(heng)重(zhong)（加權(quan)）網絡，以仿照人耳的(de)(de)接收情況，衡(heng)重(zhong)網絡對各個(ge)頻率的(de)(de)衡(heng)重(zhong)（加權(quan)）系數應契(qi)合CCITT的(de)(de)有關主(zhu)張。后，要思考測(ce)量(liang)時(shi)刻(ke)的(de)(de)影響(xiang)，噪聲電(dian)壓(ya)測(ce)量(liang)本質上是求(qiu)均勻值的(de)(de)進(jin)程(cheng)，求(qiu)均勻應在無限(xian)的(de)(de)時(shi)刻(ke)內進(jin)行，在有限(xian)時(shi)刻(ke)內測(ce)量(liang)噪聲只能(neng)得(de)到均勻值的(de)(de)估量(liang)值，這種過失本身是一個(ge)隨機(ji)變量(liang)，會使表針發生顫動。