電大20xx年最新機(jī)電控制工程基礎(chǔ)期末復(fù)習(xí)模擬試題考試題庫(kù)資料匯總(參考版)
2025-03-26 11:06本頁(yè)面
【正文】 an.Lou held a joint interview with 27 media, including China Daily, the first in a series of interviews entitled Chinese Media Along the Silk Road. The interviews will be in Shaanxi and Gansu provinces and the Xinjiang Uygur autonomous region, as well as Kazakhstan, Uzbekistan and Turkey.The media group held the first interview on Wednesday morning in Xi39。s public security bureau shows some 100 foreign visitors enjoyed the 72hour policy by the end of March, most of them from the United States, the United Kingdom and Germany. Chengdu also reported robust growth in its overall tourist industry last year. Official statistics show that it received some 150 million tourists last year, an increase of 28 percent from 2012. Around million came from abroad, an increase of 12 percent. Total revenue from tourism surpassed 133 billion yuan ($). During his visit to Kazakhstan in September, Chinese President Xi Jinping proposed that China and Central Asia join hands to build a Silk Road economic belt to boost cooperation. The idea has been widely echoed in Central Asian countries, being an encouraging blueprint for Chinese areas along the Silk Road that has linked Asia and Europe for more than 2,000 years. In the next three weeks, China Daily reporters will travel through the belt in China and in Kazakhstan, Uzbekistan and Turkey. They will show the progress and expectations of the countries, businesses and peoples on the route. Shaanxi the start of the ancient Silk Road has positioned itself as the new starting point for the development of the Silk Road Economic Belt, which will strengthen China39。s ancient indigenous religion, while Du jiang yan is considered to be the oldest functioning watercontrol project in the world. Chengdu ranked third in tourist facilities, management and services among 60 Chinese cities in a customer satisfaction survey released last year. But, Li added that efforts are still needed to develop more tourism products, improve English services and provide accurate translation of traffic signs and scenic billboards. Zhao Yun, chairwoman of British Chamber of Commerce Southwest China, told China Daily that his colleagues found the policy very convenient. A British client once flew here and stayed for just one day to check her ordered goods, she said. Zhao was born in Shanxi province, but she has lived in Chengdu for more than 10 years. My life was like a running race moving from place to place. I also lived in Beijing and Shanghai before, she said. But Chengdu is a place that you never want to leave once settling down. It is now my second hometown, she said. If the environment is further improved, the city will attract more people to visit and live, with the 72hour visafree policy and pelling conditions in transportation, culture, climate and cuisine, he said. Foreigners also gave positive feedback on the policy. A spokesman from Dell Inc said the pany has a global hub of operation in Chengdu, so the threeday visa has an immediate and positive influence on the pany39。s level of internationalization. The policy will also bring direct economic revenue, Li said. Chengdu has many cultural legacies and is also a paradise for panda lovers with the world39。Visafree policy brings Chengdu biz, tourism boost. Making national headlines several times, Chengdu39。答案：零初始 線性定常 輸入是非題：1．微分方程可以作為系統(tǒng)的動(dòng)態(tài)數(shù)學(xué)模型,傳遞函數(shù)不能作為系統(tǒng)的動(dòng)態(tài)數(shù)學(xué)模型 錯(cuò)誤單項(xiàng)選擇題1．自動(dòng)控制系統(tǒng)按照控制方式的特點(diǎn)可以分為開(kāi)環(huán)控制、閉環(huán)和復(fù)合控制三種類(lèi)型，其中 C 是三種控制類(lèi)型中最完善的方式。5． 若，則。4．若連續(xù)時(shí)間函數(shù)的變換為，當(dāng)t 0時(shí)， , 則。3. 求的變換結(jié)果是。 錯(cuò)誤解析：采樣序列f(k)=0，1，0，1，0，1 ……根據(jù)z變換的定義： =+++ …… 這是一個(gè)等比數(shù)列，如果||1，則。這種方法有時(shí)給不出一個(gè)閉式表達(dá)式。（ ）A. B. 1 C. D.答: A解析：?jiǎn)挝浑A躍函數(shù)在任何采樣時(shí)刻的值均為1，即采樣后脈沖序列為 依據(jù)z變換定義： （1）式兩邊乘以，得 （2）將式（1）式與（2）式相減得 三、判斷1． 長(zhǎng)除法有時(shí)結(jié)果不是一個(gè)完整的閉式表達(dá)式。答案B符合要求。其中，是信號(hào)有效頻譜的最高頻率。９．已知連續(xù)信號(hào)，那么采樣頻率滿足以下 條件時(shí)，采樣函數(shù)能無(wú)失真地恢復(fù)到原來(lái)的連續(xù)函數(shù)。因此本題目中應(yīng)該大于等于信號(hào)有效頻譜的最高頻率的２倍，即≥2０Ｈz。（ ）A. 1Hz~10Hz B. 1Hz~1０0Hz C. ５Hz~５０Hz ~５０Hz答: D解析：根據(jù)采樣定理，采樣角頻率應(yīng)滿足如下關(guān)系:≥2。( )A. 1 B. 2 C. 3 D. 1/2答: B解析：很容易看出長(zhǎng)除的結(jié)果第1項(xiàng)是2，因此、所對(duì)應(yīng)的的第1項(xiàng)是2。( )A. 至少為 B. 至少為 答: A解析：根據(jù)采樣定理的具體內(nèi)容可知，答案A正確。A. B. C. D. 答：B解析：典型的指數(shù)函數(shù)，其Z變換因此的Z變換結(jié)果是。A. B. C. D. 答:C解析：首先將函數(shù)離散化，得，依據(jù)變換定義： 兩邊同乘得 將2式相減，得 答案C正確。所以答案B正確。3. 的變換為（ ）。2. 變換的數(shù)學(xué)表達(dá)式為 。二、選擇1. 脈沖傳遞函數(shù)是 。5. s平面與z平面的對(duì)應(yīng)關(guān)系是：平面的左半平面對(duì)應(yīng)于平面上單位圓以內(nèi)，平面的虛軸對(duì)應(yīng)于平面 ，平面的右半平面，對(duì)應(yīng)于平面單位圓以外。4. 所對(duì)應(yīng)的的前三項(xiàng)是,依次是 ， ， 。3. 離散信號(hào)的數(shù)學(xué)表達(dá)式為 。
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