壓控震蕩器

   壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)簡單的(de)(de)(de)(de)說就(jiu)是(shi)(shi)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)頻(pin)(pin)率(lv)(lv)(lv)(lv)wo (t)受控(kong)(kong)(kong)(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)Vc (t)控(kong)(kong)(kong)(kong)制(zhi)(zhi)的(de)(de)(de)(de)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)。壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)一般可(ke)通過(guo)(guo)變容(rong)(rong)(rong)二(er)級管來(lai)實(shi)現。因為變容(rong)(rong)(rong)二(er)級管的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)是(shi)(shi)承外(wai)加偏置電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)(de)(de)(de)變化(hua)而變化(hua)，通過(guo)(guo)偏置電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)去控(kong)(kong)(kong)(kong)制(zhi)(zhi)變容(rong)(rong)(rong)二(er)級管電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)的(de)(de)(de)(de)控(kong)(kong)(kong)(kong)制(zhi)(zhi)達到對振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)頻(pin)(pin)率(lv)(lv)(lv)(lv)的(de)(de)(de)(de)控(kong)(kong)(kong)(kong)制(zhi)(zhi)。在鎖(suo)相(xiang)環路中壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)的(de)(de)(de)(de)輸出(chu)(chu)頻(pin)(pin)率(lv)(lv)(lv)(lv)是(shi)(shi)受鑒(jian)相(xiang)器(qi)(qi)(qi)(qi)(qi)輸出(chu)(chu)的(de)(de)(de)(de)相(xiang)位(wei)(或頻(pin)(pin)率(lv)(lv)(lv)(lv)）誤差(cha)(cha)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)制(zhi)(zhi)，當壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)的(de)(de)(de)(de)頻(pin)(pin)wo與(yu)輸入信號(hao)的(de)(de)(de)(de)頻(pin)(pin)率(lv)(lv)(lv)(lv)，七專級電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)可(ke)調(diao)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)價(jia)格(ge)(ge)，不同(tong)步時，則鑒(jian)相(xiang)器(qi)(qi)(qi)(qi)(qi)兩輸入信號(hao)(ui uo）之(zhi)間的(de)(de)(de)(de)相(xiang)位(wei)差(cha)(cha)Qe是(shi)(shi)時變的(de)(de)(de)(de)，鑒(jian)相(xiang)器(qi)(qi)(qi)(qi)(qi)輸出(chu)(chu)是(shi)(shi)與(yu)相(xiang)位(wei)（頻(pin)(pin)率(lv)(lv)(lv)(lv)）相(xiang)關(guan)的(de)(de)(de)(de)誤差(cha)(cha)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)ud (t)，七專級電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)可(ke)調(diao)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)價(jia)格(ge)(ge)，該誤差(cha)(cha)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)通過(guo)(guo)低通濾波器(qi)(qi)(qi)(qi)(qi)濾波，加到壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)上，由于相(xiang)位(wei)負反饋作用，七專級電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)可(ke)調(diao)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)價(jia)格(ge)(ge)，該控(kong)(kong)(kong)(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)Vc將(jiang)向少uo與(yu)ui之(zhi)間的(de)(de)(de)(de)頻(pin)(pin)率(lv)(lv)(lv)(lv)差(cha)(cha)的(de)(de)(de)(de)方向改變壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)的(de)(de)(de)(de)頻(pin)(pin)率(lv)(lv)(lv)(lv)，使(shi)壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)的(de)(de)(de)(de)頻(pin)(pin)率(lv)(lv)(lv)(lv)wo與(yu)輸入信號(hao)頻(pin)(pin)率(lv)(lv)(lv)(lv)同(tong)步。所(suo)以壓(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)振(zhen)蕩(dang)(dang)(dang)(dang)(dang)器(qi)(qi)(qi)(qi)(qi)可(ke)看成電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)——頻(pin)(pin)率(lv)(lv)(lv)(lv)變換器(qi)(qi)(qi)(qi)(qi)。

如何選(xuan)擇壓控晶體(ti)振(zhen)蕩器？

有(you)源石英晶(jing)體振(zhen)(zhen)蕩器(qi)分為普通振(zhen)(zhen)蕩器(qi)，溫(wen)補(bu)振(zhen)(zhen)蕩器(qi)TCXO，壓控(kong)振(zhen)(zhen)蕩器(qi)VCXO，恒溫(wen)振(zhen)(zhen)蕩器(qi)OCXO等(deng)等(deng)，從使用(yong)數量來看普通振(zhen)(zhen)蕩器(qi)和溫(wen)補(bu)振(zhen)(zhen)蕩器(qi)可觀(guan)，一個代(dai)(dai)表通用(yong)型(xing)，一個代(dai)(dai)表頻率高精度型(xing)；而(er)壓控(kong)和恒溫(wen)市場需求相(xiang)(xiang)對(dui)較少(shao)，但是從選型(xing)難易程度看，恒溫(wen)雖然(ran)代(dai)(dai)表著更高的(de)(de)技術要求，很多(duo)指(zhi)(zhi)(zhi)標(biao)要求從設計上(shang)已經達到(dao)(dao)標(biao)準，所(suo)以(yi)在選擇上(shang)相(xiang)(xiang)對(dui)簡(jian)單，而(er)壓控(kong)晶(jing)振(zhen)(zhen)它牽(qian)涉到(dao)(dao)更多(duo)的(de)(de)性(xing)能指(zhi)(zhi)(zhi)標(biao)，不(bu)同(tong)性(xing)能指(zhi)(zhi)(zhi)標(biao)其(qi)用(yong)法及(ji)成本(ben)均有(you)很大(da)的(de)(de)差異，所(suo)以(yi)在這里對(dui)壓控(kong)晶(jing)振(zhen)(zhen)的(de)(de)選型(xing)做相(xiang)(xiang)關的(de)(de)介紹 。

電(dian)壓控制振蕩器(qi) (VCO) 的基礎知識

許多電子應用(yong)需(xu)要根(gen)據其(qi)他(ta)信(xin)號(hao)的幅值(zhi)來改變(bian)某(mou)個信(xin)號(hao)的頻(pin)(pin)率。調頻(pin)(pin)信(xin)號(hao)便是(shi)一個很(hen)好的例子，電壓可調振(zhen)(zhen)蕩器價格(ge)，其(qi)中的載波頻(pin)(pin)率隨著(zhu)調制(zhi)源幅值(zhi)的變(bian)化(hua)而變(bian)化(hua)。此外(wai)，還有鎖相環 (PLL)：這(zhe)種電路(lu)使用(yong)控制(zhi)系統來改變(bian)振(zhen)(zhen)蕩器的頻(pin)(pin)率和/或相位，以匹配輸入參考信(xin)號(hao)的頻(pin)(pin)率/相位。

設計(ji)者的(de)目標是：確(que)定如何盡可能以低(di)成本的(de)方式實現(xian)該功(gong)能，同(tong)時確(que)保精(jing)度(du)、可靠性(xing)以及不受時間和(he)溫度(du)影(ying)響(xiang)的(de)穩定性(xing)。

這就是(shi)壓控振(zhen)蕩器(qi) (VCO) 的(de)功能。這類器(qi)件用(yong)于(yu)提供一種頻率會在(zai)合理(li)的(de)范(fan)圍(wei)內隨輸入(ru)信號的(de)電壓幅值(zhi)變化而變化的(de)輸出信號。壓控振(zhen)蕩器(qi)可用(yong)于(yu) PLL、頻率和(he)相位調制器(qi)、雷(lei)達和(he)許(xu)多其他(ta)電子系統中。