If the spectrum of a non-periodic signal [img=31x25]1803377b0f6359c.png[/img] is [img=50x25]1803377b19411c6.png[/img], then they are in one-to-one correspondence.
举一反三
- Given the spectrum [img=21x22]18033774ad81d04.png[/img] of a continuous-time signal is shown below, then, the periodic signal signal [img=50x25]18033774b570388.png[/img][img=295x129]18033774bfda33c.png[/img] A: [img=142x20]18033774c806bc3.png[/img] B: [img=133x20]18033774d008a32.png[/img] C: [img=199x25]18033774d8e0526.png[/img] D: [img=138x21]18033774e1e1bd2.png[/img]
- A signal [img=31x25]180337753aac202.png[/img] is shown below. The spectrum [img=48x25]18033775432e570.png[/img] of the signal is[img=416x139]180337754d353c7.png[/img] A: [img=96x25]18033775563d2a3.png[/img] B: [img=105x25]180337755f42026.png[/img] C: [img=105x25]18033775699e52a.png[/img] D: [img=101x25]18033775720fb34.png[/img]
- Assuming that the frequency of the signal [img=31x25]180337767ae11c2.png[/img] is [img=81x23]1803377683e48f0.png[/img], if one samples the signal [img=49x25]180337768bcc185.png[/img], to avoid aliasing, what is the maximum of the sampling interval [img=34x22]180337769434696.png[/img]? A: [img=20x46]180337769c1020b.png[/img] B: [img=29x46]18033776a4a1b6f.png[/img] C: [img=29x46]18033776aee8f94.png[/img] D: [img=20x46]18033776b79a6b5.png[/img]
- 在下列命题中:如果f(x)=[img=28x44]17e0bf9914bb2f1.png[/img],那么[img=27x29]17e0bf97582597b.png[/img]f(x)=0;如果f(x)=[img=28x44]17e0bf992111a1c.png[/img],那么[img=27x29]17e0bf97582597b.png[/img]f(x)=0;如果f(x)=[img=55x44]17e0bf992d8de0a.png[/img],那么[img=29x29]17e0bf9939482bb.png[/img]f(x)不存在;如果f(x)=[img=87x53]17e0bf99450fa82.png[/img],那么[img=27x29]17e0bf97582597b.png[/img]f(x)=0。其中错误命题的个数是( A: 0 B: 1 C: 2 D: 3
- 设f(x)在|x|>;a上有定义，若___________，使得当|x|>;X时，恒有|f(x)-A|<;ε, 称[img=57x14]17de8197cad5b33.png[/img]时函数f(x)有极限A，记作[img=33x32]17de8197d6e5e38.png[/img][img=71x25]17de8197e309ab5.png[/img]。 A: 存在ε>;0, 存在X>;0 B: 任意ε>;0, 存在X>;0 C: 存在ε>;0, 任意X>;0 D: 任意ε>;0, 任意X>;0