功率放大器的P1dB、P3dB和PSat等指標參數是(shi)大家都(dou)耳熟能詳的，但(dan)是(shi)具體是(shi)什么(me)意思有些新手工程師可能不(bu)太熟悉，下面就讓安泰(tai)電子來(lai)為大家介紹功率放大器(qi)這些指標參數的意思。

　　（1）P1dB

　　P1dB，即1分貝壓(ya)縮輸(shu)(shu)(shu)(shu)出功(gong)(gong)(gong)率(lv)，是指相(xiang)對于放(fang)大(da)器(qi)的小信號增(zeng)(zeng)(zeng)益(yi)，放(fang)大(da)器(qi)增(zeng)(zeng)(zeng)益(yi)減(jian)小1dB時(shi)的輸(shu)(shu)(shu)(shu)出功(gong)(gong)(gong)率(lv)。放(fang)大(da)器(qi)有一(yi)個(ge)線(xian)性(xing)(xing)動態(tai)范(fan)圍，在(zai)這個(ge)范(fan)圍內，放(fang)大(da)器(qi)的輸(shu)(shu)(shu)(shu)出功(gong)(gong)(gong)率(lv)隨(sui)輸(shu)(shu)(shu)(shu)入功(gong)(gong)(gong)率(lv)線(xian)性(xing)(xing)增(zeng)(zeng)(zeng)加(jia)。隨(sui)著輸(shu)(shu)(shu)(shu)入功(gong)(gong)(gong)率(lv)的繼續增(zeng)(zeng)(zeng)加(jia)，放(fang)大(da)器(qi)進入非(fei)線(xian)性(xing)(xing)區，其輸(shu)(shu)(shu)(shu)出功(gong)(gong)(gong)率(lv)不再隨(sui)輸(shu)(shu)(shu)(shu)入功(gong)(gong)(gong)率(lv)的增(zeng)(zeng)(zeng)加(jia)而線(xian)性(xing)(xing)增(zeng)(zeng)(zeng)加(jia)，也就是說，其輸(shu)(shu)(shu)(shu)出功(gong)(gong)(gong)率(lv)低于小信號增(zeng)(zeng)(zeng)益(yi)所預(yu)計的值(zhi)。通常把增(zeng)(zeng)(zeng)益(yi)下(xia)降到比(bi)線(xian)性(xing)(xing)增(zeng)(zeng)(zeng)益(yi)低1dB時(shi)的輸(shu)(shu)(shu)(shu)出功(gong)(gong)(gong)率(lv)值(zhi)定義為輸(shu)(shu)(shu)(shu)出功(gong)(gong)(gong)率(lv)的1dB壓(ya)縮點，用P1dB表(biao)示。

　　（2）P3dB

　　P3dB，即3分貝壓縮輸出(chu)功率(lv)，是指相對于放大器的小(xiao)(xiao)信號(hao)增益(yi)，放大器增益(yi)減小(xiao)(xiao)3dB時的輸出(chu)功率(lv)。

　　（3）PSat

　　PSat，即飽(bao)(bao)和(he)輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)。當(dang)功(gong)(gong)率(lv)(lv)(lv)(lv)放大器(qi)的(de)(de)輸(shu)(shu)入功(gong)(gong)率(lv)(lv)(lv)(lv)大到某(mou)(mou)一值后，再增(zeng)(zeng)大輸(shu)(shu)入功(gong)(gong)率(lv)(lv)(lv)(lv)也不會增(zeng)(zeng)大輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)的(de)(de)大小(xiao)，該輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)稱(cheng)為(wei)飽(bao)(bao)和(he)輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)。當(dang)然(ran)這種(zhong)說法是不嚴格的(de)(de)，因(yin)為(wei)功(gong)(gong)率(lv)(lv)(lv)(lv)放大器(qi)的(de)(de)轉移特性在飽(bao)(bao)和(he)時很少表現為(wei)常(chang)數。在實際功(gong)(gong)率(lv)(lv)(lv)(lv)放大器(qi)中(zhong)，在某(mou)(mou)一個(ge)頻率(lv)(lv)(lv)(lv)處增(zeng)(zeng)加輸(shu)(shu)入功(gong)(gong)率(lv)(lv)(lv)(lv)，會使輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)減小(xiao)，而在工作頻帶內其他頻率(lv)(lv)(lv)(lv)處，輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)會慢慢增(zeng)(zeng)加。基(ji)于(yu)這點(dian)通(tong)常(chang)用相對于(yu)某(mou)(mou)一個(ge)輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)處的(de)(de)飽(bao)(bao)和(he)深度來表示(shi)，相應(ying)的(de)(de)輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)稱(cheng)為(wei)飽(bao)(bao)和(he)輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)(lv)(lv)，典型的(de)(de)測量點(dian)為(wei)6dB壓縮點(dian)。

　　（4）功率附加效率（PAE）

　　放(fang)大器(qi)線性工(gong)作區(qu)(qu)和飽(bao)和工(gong)作區(qu)(qu)之間，有一個(ge)點(dian)是功(gong)(gong)率(lv)放(fang)大器(qi)效率(lv)最高的(de)地方。到達(da)這(zhe)個(ge)點(dian)的(de)時(shi)候，增加(jia)射(she)頻(pin)輸(shu)(shu)入功(gong)(gong)率(lv)會改(gai)善(shan)射(she)頻(pin)輸(shu)(shu)出功(gong)(gong)率(lv)。超過這(zhe)個(ge)點(dian)的(de)時(shi)候，增加(jia)輸(shu)(shu)入功(gong)(gong)率(lv)只(zhi)會為設備產(chan)生更多熱量。PAE測量的(de)目標是找到這(zhe)個(ge)最佳點(dian)，即(ji)功(gong)(gong)率(lv)放(fang)大器(qi)在將輸(shu)(shu)入功(gong)(gong)率(lv)轉換(huan)為輸(shu)(shu)出功(gong)(gong)率(lv)時(shi)最有效的(de)點(dian)。

　　PAE是和(he)射(she)頻輸(shu)出功(gong)率(lv)(lv)，輸(shu)入功(gong)率(lv)(lv)以及直(zhi)流電源提供的(de)功(gong)率(lv)(lv)相關(guan)的(de)，所以我們需要(yao)同時(shi)對這些(xie)參(can)數進(jin)行(xing)測量來判(pan)斷(duan)這個點的(de)位(wei)置。所以用最流行(xing)的(de)話(hua)來說，放大器(qi)的(de)測量是跨界的(de)，直(zhi)流，射(she)頻還有時(shi)域(yu)需要(yao)同時(shi)進(jin)行(xing)。

　　圖：ATA-8000系列射頻功率放大器

　　以上就(jiu)是P1dB、P3dB和PSat、功率(lv)附加效(xiao)率(lv)（PAE）指標參數的介紹內容，如果對于功率(lv)放(fang)大(da)器還有什么不知(zhi)道或者想了解的，歡迎(ying)隨時(shi)咨(zi)詢安(an)泰(tai)電子。