【正文】 結(jié) 論 本文通過一個設(shè)計實例，介紹了利用 MATLAB 實現(xiàn) FIR 濾波器設(shè)計與濾波的三種方法，從仿真結(jié)果可以看出它們均可以達到技術(shù)指標要求，而且方法簡單、快捷，大大減輕了工作量。濾波器的設(shè)計工作完成后，可以借助于 MATLAB 的 export 操作導(dǎo)出所設(shè)計濾波器的系統(tǒng)函數(shù) H(z)。由于 MATLAB 具有強大的接口功能，仿真后的結(jié)果可以很方便的移植到 DSP、 CPLD 或 FPGA 等器件中。在實際應(yīng)用中 ,只需按要求修改濾波器參數(shù) ,并對程序作較少的改動 ,即可實現(xiàn)不同截止頻率的 FIR 濾波器 ,實用性較強 參考資料 [1] 董長虹等 . MATLAB信號處理與應(yīng)用 .北京：國防工業(yè)出版社， 2021. [2] [美 ] 著，張建華等 譯 .數(shù)字信號處理 .北京：科學(xué)出版社， 2021. [3] 張葛祥，李娜 . MATLAB仿真技術(shù)與應(yīng)用 .北京：清華大學(xué)出版社， 2021. [4] 樓順天，李博菡 . 基于 MATLAB的 系統(tǒng)分析與設(shè)計 .西安：西安電子科技大學(xué)出版社，1998. [5] 馬昌風(fēng) . 最優(yōu)化設(shè)計法及 MATLAB設(shè)計 .北京：科學(xué)出版社， 2021 [6] 張磊 . MATLAB實用教程 .北京：人民郵電出版社， 2021 [7] 陳龍等 . 數(shù)字信號處理的 MATLAB實現(xiàn) .北京：科學(xué)出版社， 2021 [8] 甘本祓 ,吳萬春 . 現(xiàn)代微波濾波器的結(jié)構(gòu)與設(shè)計 .北京 科學(xué)出版社 ， 2021 [9] [美 ] 恒里 YF拉姆 著，模擬和數(shù)字濾波器設(shè)計與實現(xiàn) .北京：人民郵電出版社， 1985 附 錄 附錄 A 窗函數(shù)實現(xiàn)程序 ： passrad=*pi。 w1=boxcar(61)。 w2=hamming(61) n=1:1:61。 hd=sin(passrad*(n31))./(pi*(n31))。 hd(31)=passrad/pi。 h1=hd.*rot90(w1)。 h2=hd.*rot90(w2)。 [mag1,rad]=freqz(h1)。 [mag2,rad]=freqz(h2)。 subplot(2,2,1)。 plot(rad,20*log10(abs(mag1)))。 grid on。 title(39。designed by Rectangular window39。)。 subplot(2,2,2)。 plot(rad,20*log10(abs(mag2)))。 grid on。 title(39。designed by Hamming window39。)。 [h1,w1]=freqz(h1,1,100,2)。 subplot(2,2,3)。 plot(w1,unwrap(angle(h1)))。 grid on。 [h2,w2]=freqz(h2,1,100,2)。 subplot(2,2,4)。 plot(w2,unwrap(angle(h2)))。 grid on。 頻率采樣法實現(xiàn)程序： f=[ ]。 a=[1 0]。 dev=[ ]。 %給出濾波器的參數(shù) [n f0 a0 w]=remezord(f,a,dev)。 N=n。 alpha=(N1)/2。 k=0:N1。 wp=*pi。 ws=*pi。 %計算理想低通濾波器的截止頻率 wc=(wp+ws)/2。 m=fix(wc*N/(2*pi)+1)。 %在兩邊過渡帶取值為 的采樣點 T = 。 Hrs=[ones(1,m),T,zeros(1,N2*m1),T,ones(1,m1)]。 k1 = 0:floor(alpha)。 k2 = floor(alpha+1):N1。 phai=[alpha*(2*pi)/N*k1,alpha*(2*pi)/N*(N k2)]。 H =Hrs.*exp(j*phai)。 %計算單位沖激響應(yīng) h =ifft(H,N)。 [h1,w1] = freqz(h,1,256,1)。 hr = abs( h1)。 h1 = 20* log10(hr)。 %畫出 FIR DF 的單位取樣響應(yīng) figure(1)。 k=0:N1。 stem(k,h,39。k.39。) axis([0,N1,*min(real(h)),*max(real(h))])。 xlabel(39。n39。)。 ylabel(39。h(n)39。)。 grid on。 %畫出 FIR DF 的低通衰減幅頻特性 figure(2)。 plot(w1,h1)。 xlabel(39。Normalized39。) Frequency(πrad/sample)39。)。 ylabel(39。Magnitude(dB)39。)。 grid on。 最優(yōu)化設(shè)計程序?qū)崿F(xiàn) ： fs =2021。 %采樣頻率 rp =3。 %通帶 波紋 rs =40。 %阻帶波紋 f = [500 600]。 %截止頻率 a = [1 0]。 %期望的幅度 dev= [(10^(rp/20) 1)/ (10^(rp/20) + 1) 10^( rs/20) ]。 [n ,fo ,ao ,w] = remezord(f ,a ,dev,fs) 。 b = remez(n ,fo ,ao ,w) 。 %調(diào)用最優(yōu)設(shè)計法中 remez 函數(shù) reqz(b ,1 ,1024 ,fs)。附錄：外文翻譯 In Wang Zuoliang?s translation practices, he translated many poems, especially the poems written by Robert Burns. His translation of Burn?s “A Red, Red Rose” brought him fame as a verse translator. At the same time, he published about ten papers on the translation of poems. Some argue that poems cannot be translated. Frost stresses that poetry might get lost in translation. According to Wang, verse translation is possible and necessary, for “The poettranslator brings over some exciting work from another culture and in doing so is also writing his own best work, thereby adding something to his culture. In this transmission and exchange , a richer, more colorful world emerges. ”(Wang, 1991:112). Then how can we translate poems? According to Wang?s understanding, the translation of poems is related to three aspects: A poem?s meaning, poetic art and language. （ 1） A poem?s meaning “Sociocultural differences are formidable enough, but the matter is made much more plex when one realizes that meaning does not consist in the meaning of words only, but also in syntactical structures, speech rhythms, levels of style.” (Wang, 1991:93). （ 2） Poetic art According to Wang, “Bly?s point about the ?marvelous translation? being made possible in the United States only after Whitman, Pound and Williams Carlos Williams posed poetry in speech rhythms shows what may be gained when there is a genuine revolution in poetic art.” (Wang, 1991:93). （ 3） Language “Sometimes language stays static and sometimes language stays active. When language is active, it is beneficial to translation” “This would require this kind of intimate understanding, on the part of the translator, of its genius, its idiosyncrasies, its past and present, what it can do and what it choose not to do.” (Wang, 1991:94). Wang expresses the difficulties of verse translation. Frost?s ment is sufficient to prove the difficulty a translator has to grapple with. Maybe among literary translations, the translation of poems is the most difficult thing. Poems are the crystallization of wisdom. The difficulties of poetic prehension lie not only in lines, but also in structure, such as cadence, rhyme, metre, rhythm, all these conveying information. One point merits our attention. Wang not only talks about the times? poetic art, but also the impact language?s activity has produced on translation. In times when the language is active, translation is prospering. The reform of poetic art has improved the translation quality of poems. For example, around May Fourth Movement, Baihua replaced classical style of writing, so the translation achieved earthshaking success. The relation between the state of language and translation is so 內(nèi)部資料 請勿外傳 9JWKf wvGt YM*Jgamp。 6a*CZ7H$dq8Kqqf HVZFedswSyXTyamp。 QA9wkxFyeQ^! djsXuyUP2kNXpRWXm Aamp。 UE9aQ@Gn8xp$Ramp。849Gx^Gj qv^$UE9wEwZQc@UE%amp。 qYp@Eh5pDx2zVkumamp。 gTXRm 6X4NGpP$vSTTamp。ksv*3t nGK8!z89Am YWpazadNuKNamp。MuWFA5uxY7JnD6YWRr Wwc^vR9CpbK!zn%Mz849Gx^Gj qv^$UE9wEwZQc @UE% amp。 qYp@Eh5pDx2zVkum amp。gTXRm 6X4NGpP$vSTTamp。 ksv*3t nGK8! z89A