Patent ID: 11898453
Assignee: XI'AN JIAOTONG UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC F  G | IPC F  G

Claim 4:
5. The method according to claim 1, wherein in the third step (S3), the intercepted two segments of discrete displacement data are subjected to discrete Fourier transform to obtain the spectrum data,, X
    ⁡
    (
    k
    )
   
   =
   
    
     
      ∑
      
       n
       =
       0
      
      
       N
       -
       1
      
     
     
      
       x
       ⁡
       (
       n
       )
      
      ⁢
      
       cos
       ⁡
       (
       
        
         2
         ⁢
         π
         ⁢
         k
         ⁢
         n
        
        N
       
       )
      
     
    
    -
    
     i
     ⁢
     
      
       ∑
       
        n
        =
        0
       
       
        N
        -
        1
       
      
      
       
        x
        ⁡
        (
        n
        )
       
       ⁢
       
        sin
        ⁡
        (
        
         
          2
          ⁢
          π
          ⁢
          k
          ⁢
          n
         
         N
        
        )
       
      
     
    
   
  
  ,, where x(n) is a signal obtained by sampling, i is an imaginary number symbol, i=√{square root over (−1)}, N is a length of an acquired signal, x is the number of elements, n is an iteration number, traversing is performed from 0 to N−1, that is, all elements in x are taken, k is an integer from 0 to N−1, and X(k) represents kth data after discrete Fourier transform.