采樣 sampling; take sample 隨意采樣 take a random sample; 重復(fù)采樣 duplicate sampling; 采樣檢驗的結(jié)果表明牛奶中的脂肪含量達標(biāo)。 the results of the sample for the test have shown that the quantity of fatty substance in milk is appropriate to the standard
Firstly introduced the basic theory and method with which the analog signal can be convert to digital form , including sampling theory and course , quantification and quantification error , coding , beside those we discussed some applications of sampling technology , the reason of frequency mixture and the method to eliminate it chapter 4 introduced analog mux - switch , for the reason of simpleness we only introduce it briefly 從第3章開始,對數(shù)據(jù)采集的基本理論進行討論,首先介紹了模擬信號數(shù)字化處理中的基本理論、方法,包括采樣過程、采樣定理、量化與量化誤差、編碼,還討論了幾種采樣技術(shù)的應(yīng)用、頻率混淆產(chǎn)生的原因及消除措施。第4章,介紹了模擬多路開關(guān)。
On the basis of high speed hybrid filter banks adc system , a kind of downsampler model based on bandpass sampling theorem is presented , and analyzed , proved in time and frequency domain , in addition a downsampler is designed according to the model . a class of high effective hybrid filter banks adc system which bases on the downsampler and radio frequency spectrum is proposed , of which digital signal rate falls m times as fast as the former 作者提出了一種基于帶通采樣定理的抽取器數(shù)學(xué)模型,對該數(shù)學(xué)模型進行了時域、頻域的分析證明后,設(shè)計了一種基于該數(shù)學(xué)模型的抽取器,進而根據(jù)無線電射頻信號頻譜的特點,提出了高效混合濾波器組adc系統(tǒng),其數(shù)字信號輸出速率比高速混合濾波器組adc系統(tǒng)降低m - 1倍。
Software radio which promises well needs a kind of wideband high speed and resolution adc , but at present it is hard to realize . on the basis of the theory of multirate signal processing , the theory of filters , bandpass sampling theorem and adc principium , perfect reconstruction quadrature mirror filter ( prqmf ) banks adc system is proposed 基于此背景,本文在融合多速率數(shù)字信號處理理論、濾波器理論、帶通采樣定理以及adc原理的基礎(chǔ)上,提出了prqmf濾波器組adc系統(tǒng),并對該adc系統(tǒng)的原理、結(jié)構(gòu)、特性進行了探討和研究,其主要結(jié)論和創(chuàng)新之處如下: 1
Analyze , design and simulate the digital down - convert frequency . first , the analogue if signal is converted to digital if signal in one a / d convertor which used passband sampling theory . the digital if signal is then passed to a pair of digital mixers operating in phase quadrature for mixing the if signal to baseband signal 首先利用帶通采樣定理對中頻模擬信號進行a / d變換后將其混頻到基帶,然后用平方根升余弦滾降濾波器同時完成低通濾波和匹配濾波雙重作用,以提高解調(diào)器的效率。
The signal we named it fundamental wave ; according to the fundamental wave , coefficients of the fundamental wave can be lined in a sequence . when the unique of the dissolve of the fundamental wave can be confirmed , the sequence of the coefficients can be regarded as one of representation forms of the signal itself ; theory of dissolvable signal shows that when order of the matrix of fundamental wave sampling equals to number of fundamental waves , the sequence of the sampling values from sampling points must be matched one by one with the sequence of the coefficients of fundamental waves . the sampling composed by sequences of the sampling values must be full sampling ; the relevant deductions of the theory of dissolvable signal shows that when sampling the signal , sampling frequency must be lager than the ratio of the number of fundamental waves to the occupation time of the fundamental waves ; to band - limited signals , when the fundamental wave is a sine signal , the results from the relevant deductions of theory of dissolvable signal is coherent to the classic sampling theory 本文通過分析認(rèn)為,當(dāng)信號集中的任一信號可表示為一系列已知信號的線性代數(shù)和時,信號集便構(gòu)成可分解信號集,已知信號稱為基波信號;對可分解信號而言,基波系數(shù)構(gòu)成一序列,當(dāng)對指定的基波信號集分解唯一確定時,系數(shù)序列本身便是信號的一個表示;可分解信號采樣定理指出當(dāng)基波樣值矩陣的秩等于基波數(shù)時,則由采樣點處的采樣樣構(gòu)成的樣值序列必與基波系數(shù)序列一一對應(yīng),從而由該樣值序列構(gòu)成的采樣必為完全采樣;可分解信號采樣定理中的推論指出,對信號集進行采樣,采樣頻率必須大于其信號分解的基波數(shù)與其對應(yīng)時長之比;對有限帶寬信號,若基波信號為正弦信號時,由可分解信號采樣定理推論給出的結(jié)論與經(jīng)典采樣定理一致。
The bottleneck of hybrid filter banks adc system is that it cannot sample directly higher radio frequency signal because of lower analog input bandwidth of its adc . in order to remove it , a kind of downsampler model based on nyquist and bandpass sampling theorem is presented , analyzed and proved in time and frequency domain , in addition a downsampler is designed according to the model . on the basis of hybrid filter banks adc system , a class of high speed hybrid filter banks adc system is proposed 針對混合濾波器組adc系統(tǒng)因其adc模擬輸入帶寬低而不能對頻率較高的射頻模擬信號進行模/數(shù)轉(zhuǎn)換的瓶頸,作者提出了一種基于nyquist采樣定理和帶通采樣定理的抽取器數(shù)學(xué)模型,對該數(shù)學(xué)模型進行了時域、頻域的分析證明后,設(shè)計了一種基于該數(shù)學(xué)模型的sha抽取器,進而在混合濾波器組adc系統(tǒng)的基礎(chǔ)上,提出了高速混合濾波器組adc系統(tǒng)。