用MATLAB计算两个有限长时域序列线性卷积的命令是（ ）
A: yn=fft(x1n,N)
B: yn=fft(n,m)
C: yn=conv(x1n,x2n)
D: yn=fft(x1n,x2n)
A: yn=fft(x1n,N)
B: yn=fft(n,m)
C: yn=conv(x1n,x2n)
D: yn=fft(x1n,x2n)
举一反三
- 设x(n)是长度为2N的有限长实序列，X(k)为x(n)的2N点DFT。(1)试设计用一次N点FFT完成计算X(k)的高效算法。(2)若已知X(k)，试设计用一次N点IFFT实现求x(n)的2N点IDFT运算。
- 已知()y()=()ln()x(),则()y()(()n())()=()。A.()(()−()1())()n()n()!()x()−()n()"()role="presentation">()(()−()1())()n()n()!()x()−()n();()B.()(()−()1())()n()(()n()−()1())()!()x()−()2()n()"()role="presentation">()(()−()1())()n()(()n()−()1())()!()x()−()2()n();()C.()(()−()1())()n()−()1()(()n()−()1())()!()x()n()"()role="presentation">()(()−()1())()n()−()1()(()n()−()1())()!()x()-n();()D.()(()−()1())()n()−()1()n()!()x()−()n()+()1()"()role="presentation">()(()−()1())()n()−()1()n()!()x()−()n()+()1().
- \( {1 \over {1 + x}} \)的麦克劳林公式为（ ）。 A: \( {1 \over {1 + x}} = 1 + x + { { {x^2}} \over 2} + \cdots + { { {x^n}} \over {n!}} + o\left( { { x^n}} \right) \) B: \( {1 \over {1 + x}} = 1 + x + {x^2} + \cdots + {x^n} + o\left( { { x^n}} \right) \) C: \( {1 \over {1 + x}} = 1 - x + {x^2} - \cdots + {( - 1)^n}{x^n} + o\left( { { x^n}} \right) \) D: \( {1 \over {1 + x}} = 1 - x - { { {x^2}} \over 2}- \cdots - { { {x^n}} \over {n!}} + o\left( { { x^n}} \right) \)
- 计算下列序列的N点DFT。(1)x(n)=1(2)x(n)=δ(n)(3)x(n)=δ(n一n0)，0＜n0＜N(4)x(n)=Rm(n)，0＜m＜N(7)x(n)=ejω0nRN(n)(8)x(n)=sin(ω0n)RN(n)(9)x(n)=cos(ω0n)RN(n)(10)x(n)=nRN(n)
- \( {1 \over {1 + x}} \)的麦克劳林公式为（ ）. A: \( {1 \over {1 + x}} = 1 + x + { { {x^2}} \over 2} + \cdots + { { {x^n}} \over {n!}} + o\left( { { x^n}} \right) \) B: \( {1 \over {1 + x}} = 1 + x + {x^2} + \cdots + {x^n} + o\left( { { x^n}} \right) \) C: \( {1 \over {1 + x}} = 1 - x + {x^2} - \cdots + {( - 1)^n}{x^n} + o\left( { { x^n}} \right) \)