濾波器的發(fā)展史外文翻譯

1、<p>　　南 京 理 工 大 學(xué)</p><p>　　畢業(yè)設(shè)計(jì)(論文)外文資料翻譯</p><p>　　教 學(xué) 點(diǎn)： 無錫科技職業(yè)學(xué)院 </p><p>　　專 　業(yè)： 電子工程 </p><p>　　姓 　名： 曾凡

2、 </p><p>　　學(xué) 　號(hào)： 024910201104 </p><p>　　外文出處： History of the development </p><p>　　of the filter </p><p>　　附 件： 1.外文資料翻譯譯文；2.外文原文。 &

3、lt;/p><p>　　附件1：外文資料翻譯譯文</p><p><b>　　濾波器的發(fā)展史</b></p><p>　　1917年美國和德國科學(xué)家分別發(fā)明了LC濾波器，次年導(dǎo)致了美國第一個(gè)多路復(fù)用系統(tǒng)的出現(xiàn)。20世紀(jì)50年代無源濾波器日趨成熟。自60年代起由于計(jì)算機(jī)技術(shù)、集成工藝和材料工業(yè)的發(fā)展，濾波器發(fā)展上了一個(gè)新臺(tái)階，并且朝著低功耗、高精度、

4、小體積、多功能、穩(wěn)定可靠和價(jià)廉方向努力，其中小體積、多功能、高精度、穩(wěn)定可靠成為70年代以后的主攻方向。</p><p><b>　　一、濾波器發(fā)展引言</b></p><p>　　凡是有能力進(jìn)行信號(hào)處理的裝置都可以稱為濾波器。在近代電信設(shè)備和各類控制系統(tǒng)中，濾波器應(yīng)用極為廣泛；在所有的電子部件中，使用最多，技術(shù)最為復(fù)雜的要算濾波器了。濾波器的優(yōu)劣直接決定產(chǎn)品的優(yōu)劣，

5、所以，對濾波器的研究和生產(chǎn)歷來為各國所重視。</p><p>　　導(dǎo)致RC有源濾波器、數(shù)字濾波器、開關(guān)電容濾波器和電荷轉(zhuǎn)移器等各種濾波器的飛速發(fā)展，到70年代后期，上述幾種濾波器的單片集成已被研制出來并得到應(yīng)用。80年代，致力于各類新型濾波器的研究，努力提高性能并逐漸擴(kuò)大應(yīng)用范圍。90年代至現(xiàn)在主要致力于把各類濾波器應(yīng)用于各類產(chǎn)品的開發(fā)和研制。當(dāng)然，對濾波器本身的研究仍在不斷進(jìn)行。</p><

6、p>　　我國廣泛使用濾波器是50年代后期的事，當(dāng)時(shí)主要用于話路濾波和報(bào)路濾波。經(jīng)過半個(gè)世紀(jì)的發(fā)展，我國濾波器在研制、生產(chǎn)和應(yīng)用等方面已納入國際發(fā)展步伐，但由于缺少專門研制機(jī)構(gòu)，集成工藝和材料工業(yè)跟不上來，使得我國許多新型濾波器的研制應(yīng)用與國際發(fā)展有一段距離。</p><p><b>　　二、濾波器的分類</b></p><p>　　濾波器有各種不同的分類，一般有

7、如下幾種。</p><p>　?。?）按處理信號(hào)類型分類</p><p>　　按處理信號(hào)類型分類，可分為模擬濾波器和離散濾波器兩大類。其中模擬濾波器又可分為有源、無源、異類三個(gè)分類；離散濾波器又可分為數(shù)字、取樣模擬、混合三個(gè)分類。當(dāng)然，每個(gè)分類又可繼續(xù)分下去，總之，它們的分類可以形成一個(gè)樹形結(jié)構(gòu)，實(shí)際上有些濾波器很難歸于哪一類，例如開關(guān)電容濾波器既可屬于取樣模擬濾波器，又可屬于混合濾波器，

8、還可屬于有源濾波器。因此，我們不必苛求這種“精確”分類，只是讓人們了解濾波器的大體類型，有個(gè)總體概念就行了。</p><p>　?。?）按選擇物理量分類</p><p>　　按選擇物理量分類，濾波器可分為頻率選擇、幅度選擇、時(shí)間選擇（例如PCM制中的話路信號(hào)）和信息選擇（例如匹配濾波器）等四類濾波器。</p><p>　?。?）按頻率通帶范圍分類</p>

9、<p>　　按頻率通帶范圍分類，濾波器可分為低通、高通、帶通、帶阻、全通五個(gè)類別，而梳形濾波器屬于帶通和帶阻濾波器，因?yàn)樗兄芷谛缘耐◣Ш妥鑾А?lt;/p><p>　　濾波器種類繁多，有些是眾所周知的，有些可能不為大家所熟悉，下面著重介紹近年來發(fā)展很快的幾種濾波器。</p><p><b>　　三、有源濾波器 </b></p><p&g

10、t;　　有源濾波器由下列一些有源元件組成：運(yùn)算放大器、負(fù)電阻、負(fù)電容、負(fù)電感、頻率變阻器（FDNR）、廣義阻抗變換器（GIC）、負(fù)阻抗變換器（NIC）、正阻抗變換器（PIC）、負(fù)阻抗倒置器（NII）、正阻抗倒置器（PII）、四種受控源，另外，還有病態(tài)元件極子和零子。</p><p>　　1965年單片集成運(yùn)算放大器問世后，為有源濾波器開辟了廣闊的前景。70年代初期，有源濾波器發(fā)展引人注目，1978年單片RC有源濾

11、波器問世，為濾波器集成邁進(jìn)了可喜的一步。由于運(yùn)放的增益和相移均為頻率的函數(shù)，這就限制了RC有源濾波器的頻率范圍，一般工作頻率為20kHz左右，經(jīng)過補(bǔ)償后，工作頻率也限制在100kHz以內(nèi)。1974年產(chǎn)生了更高頻的RC有源濾波器，使工作頻率可達(dá)GB/4（GB為運(yùn)放增益與帶寬之積）。由于R的存在，給集成工藝造成困難，于是又出現(xiàn)了有源C濾波器：就是濾波器由C和運(yùn)放組成。這樣容易集成，更重要的是提高了濾波器的精度，因?yàn)橛性碈濾波器的性能只取決于

12、電容之比，與電容絕對值無關(guān)。但它有一個(gè)主要問題：由于各支路元件均為電容，所以運(yùn)放沒有直流反饋通道，使穩(wěn)定性成為難題。1982年由Geiger、Allen和Ngo提出用連續(xù)的開關(guān)電阻（SR）去替代有源RC濾波器中的電阻R，就構(gòu)成了SRC濾波器，它仍屬于模擬濾波器。但由于采用預(yù)置電路和復(fù)雜的相位時(shí)鐘，使這種濾波器發(fā)展前途不大。</p><p>　　總之，由RC有源濾波器為原型的各類變種有源濾波器去掉了電感器，體積小，

13、Q值可達(dá)1000，克服了RLC無源濾波器體積大，Q值小的缺點(diǎn)。但它仍有許多課題有待進(jìn)一步研究：理想運(yùn)放與實(shí)際特性的偏差的研究；由于有源濾波器混合集成工藝的不斷改進(jìn)，單片集成有待進(jìn)一步研究；應(yīng)用線性變換方法探索最少有源元件的濾波器需要繼續(xù)探索；元件的絕對值容差的存在，影響濾波器精度和性能等問題仍未解決；由于R存在，集成占芯片面積大，電阻誤差大（20%～30%），線性度差等缺點(diǎn)，使大規(guī)模集成仍然有困難。盡管有這么多問題，RC有源濾波器的理論

14、和應(yīng)用仍在持續(xù)發(fā)展中。</p><p>　　四、開關(guān)電容濾波器（SCF）</p><p>　　20世紀(jì)80年代技術(shù)改造一個(gè)重大課題是實(shí)現(xiàn)各種電子系統(tǒng)全面大規(guī)模集成（LSI）。使用最多的濾波器成為“攔路虎”，RC有源濾波器不能實(shí)現(xiàn)LSI，無源濾波器和機(jī)械濾波器更不用說了，于是，人們只能另辟新徑。50年代曾有人提出SCF的概念，由于當(dāng)時(shí)集成工藝不過關(guān)，并沒有引起人們的重視。1972年，美國一個(gè)

15、叫Fried的科學(xué)家發(fā)表了用開關(guān)和電容模擬電阻R，說SCF的性能只取決于電容之比，與電容絕對值無關(guān)，這樣才引起人們的重視。1979年一些發(fā)達(dá)國家單片SCF已成為商品（屬于高度保密技術(shù)）?，F(xiàn)在SC技術(shù)已趨成熟。SCF采用MOS工藝加以實(shí)現(xiàn)，被公認(rèn)為80年代網(wǎng)絡(luò)理論與集成工藝的一個(gè)重大突破。當(dāng)前MOS電容值一般為幾皮法至100pF之內(nèi)，它具有（10～100）×10-6/V的電壓系數(shù)與（10～100）×10-6/℃的溫度系

16、數(shù)，這兩個(gè)系數(shù)幾乎接近理想的境界。SCF具有下列一些優(yōu)點(diǎn)：SCF可以大規(guī)模集成；SCF精度高，因?yàn)槠湫阅苋Q于電容之比，而MOS電容之比的誤差小于千分之一；功能多，幾乎所有電子部件和功能均可以由SC技術(shù)來實(shí)現(xiàn)；比數(shù)字濾波器簡單，因?yàn)椴恍枰狝/D、D/A轉(zhuǎn)換；功能小，可以做到小于10</p><p>　　SCF的應(yīng)用以聲頻范圍應(yīng)用為主體，工作頻率在100kHz之內(nèi)。在信號(hào)處理方面的應(yīng)用有：程控SCF、模擬信號(hào)處理、

17、振動(dòng)分析、自適應(yīng)性濾波器、音樂綜合、共振譜、語言綜合器、音調(diào)選擇、語聲編碼、聲頻分析、均衡器、解調(diào)器、鎖相電路、離散傅氏變換…… 總之，SCF在儀表測量、醫(yī)療儀器、數(shù)據(jù)或信息處理等許多領(lǐng)域都有廣泛的應(yīng)用前景。</p><p>　　在我國，1978年有的導(dǎo)師和在校研究生開始進(jìn)行這項(xiàng)研究工作，真正引起人們重視是1980年以后。1983年清華大學(xué)已制成單片SCF，成都工程學(xué)院與工廠聯(lián)合，也研制成單片SCF?，F(xiàn)在關(guān)鍵是用

18、MOS工藝實(shí)現(xiàn)SCF及推廣應(yīng)用問題，由于用戶還不了解它，在我國SCF的應(yīng)用還沒有普及。</p><p>　　五、SCF還有許多課題有待研究</p><p>　　(1) 由于運(yùn)放和控制MOS開關(guān)的采樣頻率所限制，使得SCF只能在音頻范圍內(nèi)應(yīng)用。近年雖然出現(xiàn)無運(yùn)放的SC電路，但由于采樣頻率的限制，工作頻率最高只有在1MHz之內(nèi)。</p><p>　　(2) 非的MOS開

19、關(guān)的溝道電阻以及非理想的運(yùn)放特性，均可使SCF造成誤差。</p><p>　　(3) 開關(guān)電容本身的寄生電容使SCF的頻響發(fā)生畸變。 (4) MOS開關(guān)與MOS運(yùn)放的熱噪聲使SCF的動(dòng)態(tài)范圍受到限制。</p><p>　　最終要以MOS工藝來實(shí)現(xiàn)的SCF，由于它是時(shí)變網(wǎng)絡(luò)，要想用分立元件精確模擬是不可能的，這樣，設(shè)計(jì)完善的CAD技術(shù)是解決這一問題的唯一手段。此外，在靈敏度分析、噪聲分析等方

20、面均有許多課題有待研究。</p><p>　　六、幾種新型數(shù)字濾波器（DF）</p><p><b>　　(1)自適應(yīng)DF</b></p><p>　　最優(yōu)控制、自適應(yīng)控制和自學(xué)習(xí)控制都涉及到多參數(shù)、多變量的復(fù)雜控制系統(tǒng)，都屬于現(xiàn)代控制理論研究的課題。自適應(yīng)DF具有很強(qiáng)的自學(xué)習(xí)、自跟蹤功能。它在雷達(dá)和聲納的波束形成、緩變噪聲干擾的抑制、噪聲信號(hào)

21、的處理、通信信道的自適應(yīng)均衡、遠(yuǎn)距離電話的回聲抵消等領(lǐng)域獲得了廣泛的應(yīng)用，促進(jìn)了現(xiàn)代控制理論的發(fā)展。</p><p>　　自適應(yīng)DF有如下一些簡單算法：W—LMS算法、M—LMS算法、TDO算法、差值LMS算法和C—LMS算法。</p><p><b>　　(2)復(fù)數(shù)DF</b></p><p>　　在輸入信號(hào)為窄帶信號(hào)處理系統(tǒng)中，常采用復(fù)數(shù)D

22、F技術(shù)。為了降低采樣率而又保存信號(hào)所包含的全部信息，可利用正交雙路檢波法，取出窄帶信號(hào)的復(fù)包絡(luò)，然后通過A/D變換，將復(fù)包絡(luò)轉(zhuǎn)化為復(fù)數(shù)序列進(jìn)行處理，這個(gè)信號(hào)處理系統(tǒng)即為復(fù)數(shù)DF。它具有許多功能：MTI雷達(dá)中抑制具有卜勒頻移的雜波干擾；數(shù)字通信網(wǎng)與模擬通信網(wǎng)之間多路TDM/FDM信號(hào)變換復(fù)接……</p><p><b>　　(3)多維DF</b></p><p>　　在

23、圖像處理、地震、石油勘探的數(shù)據(jù)處理中都用到多維DF（常用是二維DF），多維DF的設(shè)計(jì)，往往將一維DF優(yōu)化設(shè)計(jì)直接推廣到多維DF中去。對于模糊和隨機(jī)噪聲干擾的二維圖像的處理，多維DF也能發(fā)揮很好的作用。</p><p>　　此外，還有波DF，它便于實(shí)現(xiàn)大規(guī)模集成，便于無源和有源濾波網(wǎng)絡(luò)的數(shù)字模擬。因此，正受到人們的重視和加以研究。</p><p>　　對于DF有待研究的課題有：系數(shù)靈敏度、舍

24、入噪聲和極限環(huán)、多維逆歸濾波器的穩(wěn)定性、各種硬件和軟件實(shí)現(xiàn)DF的研究等等?？傊珼F在數(shù)字信號(hào)處理技術(shù)中占有極為重要的地位，對于它的研究、生產(chǎn)和應(yīng)用等工作均是很有意義的。</p><p><b>　　七、其他新型濾波器</b></p><p>　　為適應(yīng)各種需要，出現(xiàn)了一批新型濾波器，這里介紹幾種已得到廣泛應(yīng)用的新型濾波器。</p><p>　

25、　(1)電控編程CCD橫向?yàn)V波器（FPCCDTF）</p><p>　　電荷耦合器（CCD）固定加權(quán)的橫向?yàn)V波器（TF）在信號(hào)處理中，其性能和造價(jià)均可與數(shù)字濾波器和各種信號(hào)處理部件媲美。這種濾波器主要用于自適應(yīng)濾波；P-N序列和Chirp波形的匹配濾波；通用化的頻域?yàn)V波器及相關(guān)積運(yùn)算；語音信號(hào)和相位均衡；相陣系統(tǒng)的波束合成和電視信號(hào)的重影消除等均有應(yīng)用。當(dāng)然，更多的應(yīng)用有待進(jìn)一步開拓?？傊?，F(xiàn)PCCDTF是最有希

26、望的發(fā)展方向。</p><p><b>　　(2)晶體濾波器</b></p><p>　　它是適應(yīng)單邊帶技術(shù)而發(fā)展起來的。在20世紀(jì)70年代，集成晶體濾波器的產(chǎn)生，使它的發(fā)展產(chǎn)生一個(gè)飛躍。近十年來，晶體濾波器致力于下面一些研究：實(shí)現(xiàn)最佳設(shè)計(jì)，除具有優(yōu)良的選擇外，還具有良好的時(shí)域響應(yīng)；尋求新型材料；擴(kuò)展工作頻率；改造工藝，使其向集成化發(fā)展。它廣泛應(yīng)用于多路復(fù)用系統(tǒng)中作為

27、載波濾波器，在收發(fā)信中，單邊帶通信機(jī)中作為選頻濾波器，在頻譜分析儀和聲納裝置中作為中頻濾波器。</p><p><b>　　(3)聲表面濾波器</b></p><p>　　它是理想的超高頻器件。它的幅頻特性和相位特性可以分別控制，以達(dá)到要求，而且它還有體積小，長時(shí)間穩(wěn)定性好和工藝簡單等特點(diǎn)。通常應(yīng)用于：電視廣播發(fā)射機(jī)中作為殘留邊帶濾波器；在彩色電視接收機(jī)中調(diào)諧系統(tǒng)的表

28、面梳形濾波器。此外，在國防衛(wèi)星通信系統(tǒng)中已廣泛采用。聲表面濾波器是電子學(xué)和聲學(xué)相結(jié)合的產(chǎn)物，而且可以集成，所以，它在所有無源濾波器中最有發(fā)展前途的。</p><p>　　各種新型濾波器太繁多，限于篇幅，不再一一敘述。</p><p>　　我國目前各種濾波器的應(yīng)用比例</p><p>　　我國現(xiàn)有濾波器的種類和所覆蓋的頻率已基本上滿足現(xiàn)有各種電信設(shè)備。從整體而言，我國

29、有源濾波器發(fā)展比無源濾波器緩慢，尚未大量生產(chǎn)和應(yīng)用。從下面的生產(chǎn)應(yīng)用比例可以看出我國各類濾波器的應(yīng)用情況：LC濾波器占50%；晶體濾波器占20%；機(jī)械濾波器占15%；陶瓷和聲表面濾波器各占1%；其余各類濾波器共占13%。從這些應(yīng)用比例來看，我國電子產(chǎn)品要想實(shí)現(xiàn)大規(guī)模集成，濾波器集成化仍然是個(gè)重要課題。</p><p>　　隨著電子工業(yè)的發(fā)展，對濾波器的性能要求越來越高，功能也越來越多，并且要求它們向集成方向發(fā)展。

30、我國濾波器研制和生產(chǎn)與上述要求相差甚遠(yuǎn)，為縮短這個(gè)差距，電子工程和科技人員負(fù)有重大的歷史責(zé)任。</p><p><b>　　附件2：外文原文</b></p><p>　　History of the development of the filter</p><p>　　In 1917, the U.S. and German scientis

31、ts were invented the LC filters, the following year led the United States first multiplexing systems to appear. The 1950 s mature of passive filter. Since the s with the computer technology, integrated process and materi

32、al industry development, the filter development on a new level, and low power consumption, high precision, toward small volume, multi-function, stable and reliable and inexpensive effort, including small volume, multi-fu

33、nction, high precision,</p><p>　　1, Filter development introduction</p><p>　　All have the ability to signal processing devices can be called a filter. In the modern telecommunications equipment

34、and all kinds of control system, the filter are widely; Of all the electronic components, the use of the most, the most complex technology is filter. The merits of the filter directly determine product quality, therefore

35、, to filter in the research and production has been on for all countries.</p><p>　　Cause RC active filter, digital filters, switch capacitance filter and the charge transfer of the rapid development of filte

36、r, to the 70 s, the above several filter monolithic integration has been developed and applied. In the 80 s, specialized in all kinds of new type filter research, and strive to improve performance and gradually expand th

37、e scope of application. In the 90 s to now mainly devotes to the of all kinds filter used in all kinds of product development and research. Of course, to fi</p><p>　　Our country wide use filter is 50 s and t

38、here is mainly used in road filter and report way words filter. After half a century of development, China filter in the development, production and application already into the international development pace, but due to

39、 the lack of specialized research institutions, integration process and material industry can't keep up, causing many new filter development in China and international development application for a short distance.<

40、;/p><p>　　2, The classification of the filter</p><p>　　There are different kinds of filter classification, generally has the following several kinds.</p><p>　　(1) According to deal wit

41、h signal type classification</p><p>　　According to the processing signal type classification, may be classified as analog filter and discrete filter two kinds big. One simulation and can be divided into acti

42、ve filter, passive, three different classification; Discrete filter and can be divided into digital, sampling simulation, mixed three classification. Of course, each classification and can continue to points down, in sho

43、rt, their classification can form a tree structure, in fact some filter is hard to be which kind of, such as sw</p><p>　　(2) According to choose physical quantities classification</p><p>　　Accor

44、ding to choose physical quantities classification, filter can be divided into frequency selection, amplitude selection, time to choose (such as the words of PCM signals) and information choice (for example matching filte

45、r), and other four kinds of filter.</p><p>　　(3) By frequency bandpass range classification</p><p>　　According to the classification with frequency range, filter can be divided into low pass, qu

46、alcomm, band-pass, take resistance, all the five categories, and comb form bandpass filter belong to stop filter and belt, because it has periodic bandpass and stopband.</p><p>　　Filter sort is various, some

47、 are well known, some may not be what we are familiar with, introduced in recent years the development of several filter soon.</p><p>　　3, Active filter</p><p>　　By the following active power fi

48、lter some active components: operational amplifier, the negative resistance, capacitance and inductance, negative negative frequency rheostat (FDNR), generalized impedance transformer (GIC), negative impedance transforme

49、r (NIC), are impedance transformer (PIC), negative impedance inversion device (NII), are impedance inversion device (PII), four kinds of controlled source, in addition, there is a very sick son and son zero components.&l

50、t;/p><p>　　1965 monolithic integrated operational amplifier advent, for active filter opened up broad prospects. In the early 70 s, active filter development conspicuous, 1978 single chip RC active filter come

51、out, for filter integrated into welcome step. Due to the op-amp the ripples of gain and phase-shift are of the frequency of function, this limits the range of frequencies RC filter, general working frequency for about 20

52、 kHz, after compensation, working frequency also limited to 100 kHz less than. 19</p><p>　　In short, by the RC active filter is a prototype of all kinds of variant active filter to remove inductors, small vo

53、lume, Q value can reach 1000, overcome the RLC passive filter is big, Q value of small faults. But it still has many topic needs further research: ideal op-amp and practical characteristics of the deviation; Due to the a

54、ctive filter hybrid integrated process improvement, monolithic integrated needs further research; Application linear transform method to explore the least an active</p><p>　　4, Switch capacitance filter (SCF

55、)</p><p>　　The 1980 s technology reform a major issue is the realization of various electronic system in large scale integration (LSI). Use most filters become "tiger", RC active filter can't a

56、chieve LSI, passive filter and not to mention the mechanical filter, and so, people can only additional monarch new size. 50 s there has been put forward the concept of SCF, because at that time integration process doesn

57、't pass, and did not cause the attention of people. In 1972, the United States a call Fried scient</p><p>　　The application of the SCF to audio range application as the main body, the work in 100 kHz fre

58、quency within. In signal processing applications are: SPC SCF, analog signal processing, vibration analysis, adaptive filter, music, resonance spectrum, comprehensive language integrated device, tone selection, sounds co

59、ding, audio analysis, equalizer, modem, phase locked circuit, discrete Fourier transform...... In short, SCF, medical instruments in the meter measuring and data or information processi</p><p>　　In our count

60、ry, some 1978 graduate students began to mentor and conducted the research work, and really cause people to pay attention to is 1980 years later. Tsinghua university has made 1983 single chip SCF, chengdu academy of engi

61、neering and joint factory, developed a single piece of SCF. Now the key is to use MOS process realize SCF and application of a problem, because users don't know it, in our country the application of SCF is not popula

62、r.</p><p>　　5，SCF and many of the issues need to be researched</p><p>　　(1) The op-amp and control of the MOS switch sampling frequency limit, makes the SCF can only within the scope of the audi

63、o applications. In recent years, although appear have no op-amp of the SC circuit, but because sampling frequency restrictions, the highest rate of work only in 1 MHz within.</p><p>　　(2) The MOS switch the

64、channel of resistance and the ideal op-amp characteristics, all can make SCF cause errors.</p><p>　　(3) Switch capacitance itself to the parasitic capacitance SCF frequency response distortion occurred. (4)

65、MOS switch and MOS op-amp thermal noise make SCF dynamic range was limited.</p><p>　　Finally in the process to achieve the MOS SCF, because it is time-varying network, want to use accurate simulation compone

66、nts division is not possible, such, design perfect CAD technology is the solution of this problem only means. In addition, the sensitivity analysis, noise analysis were many issues need to be researched.</p><p

67、>　　6, Several new digital filter (DF)</p><p>　　(1) The adaptive DF</p><p>　　The optimal control and adaptive control and self-learning control were related to many parameters, multivariate co

68、mplex control system, all belong to the modern control theory of research. Adaptive DF has the very strong self-learning, since the tracking function. It on the radar and sonar beamforming, slowly noise suppression, nois

69、e signal processing, the communication channel adaptive equilibrium, the echo of the long distance telephone offset, etc have gained wide application, and promote th</p><p>　　Adaptive DF has the following a

70、few simple algorithm: W-LMS algorithm, M-LMS algorithm, TDO algorithm, difference LMS algorithm and C-LMS algorithm.</p><p>　　(2) The plural DF</p><p>　　In the input signal for narrowband signal

71、 processing system, often by plural DF technology. In order to reduce the sampling rate and save signal contains all of the information, can use orthogonal double road detection method, remove narrowband signal of the co

72、mplex envelop, and then through the A/D transformation, will the complex envelop into complex sequence for processing, the signal processing system is for plural DF. It has many functions: MTI the suppression doppler rad

73、ar with doppler-shi</p><p>　　(3) The multidimensional DF</p><p>　　In image processing, earthquake, oil exploration data processing all use multidimensional DF (commonly used is 2 d DF), the desi

74、gn of the multidimensional DF, often a d DF optimization design to multi-dimensional DF direct marketing. For fuzzy and random noise interference 2 d image processing, multidimensional DF also can play a very good effect

75、.</p><p>　　In addition, still wave DF, it is easy to realize large-scale integrated, facilitate passive and active power filter network digital simulation. Therefore, is attention by people and studied.</

76、p><p>　　For DF remains to be subjects of study: coefficient sensitivity, rounding noise and limit cycle, the stability of the multidimensional inverse to filter, all kinds of hardware and software implementatio

77、n of DF research and so on. In short, DF in digital signal processing technology is very important position in possession, for its research, production and application, etc all is very meaningful.</p><p>　　7

78、, Other new filter</p><p>　　In order to adapt to all kinds of need, the emergence of a batch of new filter, presented here has been widely used several types of filters.</p><p>　　(1) Electric co

79、ntrol programming CCD horizontal filter (FPCCDTF)</p><p>　　A charge-coupled device (CCD) fixed weighted transverse filter (TF) in signal processing, the performance and cost all can with digital filter and a

80、ll kinds of signal processing unit). This filter is mainly used for adaptive filter; P-N sequence and Chirp waveform of matched filter; Generalization of frequency domain filter and related product operation; Speech sign

81、al and the phase equilibrium; Phase array systems beam synthesis and television signals</p><p>　　(2) Cystal filter</p><p>　　It is to meet with the single technology and developed. In the 1970 s,

82、 the integrated production of crystal filter, make it of development have a leap. In the last ten years, crystal filter below to some research: to achieve the best design, besides having the fine choose outside, still ha

83、ve good time domain response; Seek new materials; Extended working frequency; Modification technology, made it to the integrated development. It is widely used in multiplexed system as the carrier filter, in se</p>

84、<p>　　(3) Surface acoustic filter</p><p>　　It is the ideal uhf devices. Its amplitude frequency characteristics and phase characteristic respectively control, so as to meet the requirements, and it al

85、so has small volume, long time good stability and simple process etc. Characteristics. Usually used in: TV broadcast transmitter as residual sideband filter; The color television receivers of tuning system surface comb f

86、orm filter. In addition, in the defense satellite communication systems has been widely adopted. Surface acoustic filter is</p><p>　　Various new filter too is various, somewhere, no longer described them.<

87、;/p><p>　　Our country at present the application of various filter proportion</p><p>　　Our country's existing types of filters and the frequency of the covered has basically satisfy existing te

88、lecommunications equipment. From the overall, our country active filter development than passive filter slow, has not been a lot of production and application. From the following production application proportion of vari

89、ous types of filters can be seen, the application of the: LC filters 50%; Crystal filter accounted for 20%; Mechanical filter accounted for 15%; Ceramic filter harmonic surfa</p><p>　　Along with the developm

90、ent of the electronic industry, to filter the performance requirements of more and more high, function more and more, and asked them to integration development direction. Our country filter development and production of