nyquist rate 中文意思是什麼
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Fpga and dvb standard are introduced firstly, dvb - c standard and composition of its system are analyzed completely, development of modulator structure and dvb - c digital modulator composition are presented, more over, analysis of respective modular are given. then, principle of dvb - c digital modulator system are presented, they are error control technique 、 mqam 、 nyquist rule and root raised cosine filter 、 window design method for fir filter 、 multi - rate signal processing ( integer interpolating, conversion of fractional sampling, equal conversion of net structure, polyphase structure for filter, poly - phase structure for interpolator, multi - stage implementation of samplying conversion ) 、 distrubited algorithm 、 cic filter 、 dds 、 cordic algorithm
接著，專門利用一個章節闡述了dvb - c前端調制系統原理，他們了差錯控制技術、多進制調制（ mqam ） 、 nyquist準則與平方根升餘弦濾波器、有限沖擊響應濾波器的窗函數設計法、多抽樣率信號處理包括（整數倍內插原理、分數倍抽樣率轉換、網路結構的等效結構、濾波器的多相表示、內插器的多相表示、抽樣率轉換的多級實現） 、分散式演算法、 cic濾波器、直接數字頻率合成（ dds ） 、 cordic演算法。 -
The proposed modulator uses 0. 35um standard cmos process, the nmos and pmos threshold voltage is 0. 54 volt and - 0. 48 volt, respectively, and the power supply is 1. 5 volt. the nyquist converter rate is 50 khz, oversampling ratio is 80. the proposed modulator can obtain 98db dynamic range, 16 bits converter resolution, and fits for high - fidelity, digital - audio application
本設計採用0 . 35微米標準cmos工藝，其中nmos和pmos晶體管的閾值電壓分別為0 . 54伏和- 0 . 48伏，電源電壓為1 . 5伏，奈奎斯特轉換率為50khz ，過采樣率為80 ，該調制器可實現動態范圍98db ， 16位的轉換精度，適合高保真數字音頻應用。 -
A solution is to use a low - pass filter to eliminate frequencies higher than the nyquist rate
解決辦法是用低通濾波器濾除高於奈奎斯特頻率的成分。 -
On the basis of the former research works, we present the detecting method as follows : for the narrow band characteristic of the track signal we use under - sampling instead of nyquist sampling to reduce the sampling rate. as to the carrier frequency, the spectrum of the 18 - information frequency - shift track signal has two peaks, then the carrier frequency is the average of the two peak frequency, to um - 71 jointless track signal, it has only one peak, then the carrier frequency is the peak frequency
針對移頻軌道信號的窄帶特性提出了使用欠采樣技術代替奈奎斯特采樣的方法，以降低信號的采樣頻率;國產18信息移頻軌道信號頻譜具有雙峰，雙峰頻率平均值就是信號的載頻頻率，而um - 71無絕緣軌道信號頻譜單峰，峰值頻率即為信號的載頻頻率。 -
The system can make the total signaling rate very close to the nyquist rate of given frequency band through the use of a lot of subchannels
該系統利用大量的子通道使得總的信號速率能夠非常接近給定頻帶的奈奎斯特速率。
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