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【简答题】
调谐器输入调谐回路的作用是什么 ? 它怎样完成选频任务 ? 怎样抑制掉不需要的电台信号 ? 2.变频电路的作用是什么 ? 输入信号、本振信号、中频信号的频率有什么关系 ? 3 .在超外差式收音机中,为什么要选择差频信号作为中频信号 ? 4 .什么叫调频?调频广播有哪些特点? 5.简述磁头的结构,录音与磁头分别有哪些性能要求和工作特点? 6. 录音机的性能指标有哪些?其意义如 7 .检波与自动增益控制电路各有什么作用 ? 自动增益控制电路失效会出现什么现象 ?
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举一反三
【单选题】Mike said he would write to me as soon as he arrived ________Tokyo.
A.
in
B.
at
C.
on
D.
to
【单选题】听力原文：M: I bumped into Mike at the Cafe and he said he would come to the surprise party tonight. W: Oh, then he can join us, finally. Last time when I ran into him at the library, he still complained h...
A.
Mike will host the party tonight.
B.
She met Mike just now.
C.
She will go to the party with Mike tomorrow night.
D.
Mike could not attend the party.
【简答题】道路通行能力的运行质量条件包括: 、 、 、 。
【多选题】多选题(至少有两个选项是正确的,多选、少选、错选、不选均不得分)
A.
下面 城市将在2022年举办冬季奥运会。
B.
哈尔滨
C.
北京
D.
张家口
E.
天津
F.
石家庄
【单选题】听力原文：W: Mike said that he is looking for a job in the bookstore. M: Really? If I remember right, he had a chance to work there, but he turned it down. I thought he did not like the job. Q: What can be...
A.
He wasn't offered the job in the bookstore.
B.
He really wants to work in the bookstore.
C.
He didn't know where the bookstore was.
D.
He declined the bookstore job once.
【简答题】自动空调系统电路主要由( )电路和( )电路。
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