序列
的长度为4，序列
的长度为3，则它们线性卷积的长度和5点圆周卷积的长度分别是（ ）。
A: 7, 5
B: 5, 5
C: 6, 6
D: 6, 5
的长度为4，序列的长度为3，则它们线性卷积的长度和5点圆周卷积的长度分别是（ ）。A: 7, 5
B: 5, 5
C: 6, 6
D: 6, 5
举一反三
- 采用基2时间抽取FFT算法计算<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/f67e1917247149b497ced3c3798bea9a.png" />点序列的DFT，以下（ ）流图是正确的。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/76a32272ec1c4ab7a7efff7430a72d78.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/5398db8fd5714235b18480d2d9d3cfae.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/79bb453e60504ef195ebe4368d76c8a5.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/d521c85331ce46948d059dd2875d17e7.png" />
- 基2频率抽取FFT算法中时域序列分解的蝶形图是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/7ca0b619afd44022bf8ce67c67afd54d.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/c9e44ade5dd4492f8ff9296540f4860a.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/c24a7ec44e3b4bfc8b08bb120429ff18.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/1f93041df7124232ae9c76f2ebc8fc4c.png" />
- 下列分子中至少有两个不同长度的键的是（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/5af00c65576b488d8af49c325eb0bbf6.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/c1e895a5a9164cfd9774ac5550563acc.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/04fa9c3f0c9b436ab45597fa93aad05e.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/0010b01ce5b04033a18fa52fbe3a7c20.png" />
- 两个平行的“无限大”均匀带电平面,其电荷面密度分别为+σ和+2σ,如图所示,则A、B二个区域的电场强度分别为（设水平向右为正方向）：()<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/78e393cd69774cd39a6b01baab32e20c.png" > A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/3df0f391d8d744bd98dc43b9717002d4.png" >，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/f87c5783dc7b4f5d98e57cd626b5c95b.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/9b859042c4284348a9524474ad08eafd.png" >，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/61f01893798a4d17965826ac6341e587.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/8b8f9aea022c4e6ca7ac133abc21c16a.png" >，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/6fd6170aa1f9495c8e27a96b368c374a.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/8c0c545adfb54d5d88cfa429928d1302.png" >，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/17de9a98804d4ec09e06a5f8bce2f890.png" >
- 函数<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/80d8f8a04b644504a6d2e40a33d0eb32.png" >的<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/4b92518ac6a14134a358c16900e875c0.png" >阶麦克劳林公式为（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/7c2994f9242c43379c6a106d5bd92658.png" >； B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/2145f14f27224b189e702d3390e0a9ba.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/9ef01b77e76241d9b67b1c7c8cd0eea1.png" >； D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/a0feec59ac5046839ecb5324b27717e0.png" >；