为什么apfft选用hann窗?

matlab中有16种窗

表一是这16种窗apfft的测135度相位精度,其中精度最高e-014的4种窗是

3@blackman                     5.684341886080802e-014         0.09 -100db

5@bohmanwin                 5.684341886080802e-014          0.09 -100db

图一是这16种窗apfft的测相位谱, 10hann窗平坦最好

hann窗插值公式简明,比值校正法校正公式简单

  hann窗apFFT的初始相位是准确的，相位差也是准确的，所以频率可以准确校正, 进而频偏也是准确的. 所以振幅也可以准确校正. 无噪时hann窗apFFT的相位,频率,振幅校正精度均达10(-10).

      表一          16种窗apfft的测相精度

1@barthannwin                  3.673875426102313e-009

2@bartlett                          6.832240728726902e-008

3@blackman                     5.684341886080802e-014    0.09*pi_rad/sample      -100db

4@blackmanharris            2.987121661135461e-011

5@bohmanwin                 5.684341886080802e-014    0.09*pi_rad/sample       -100db

6@chebwin                       6.979462341405451e-009

7@flattopwin                   3.396280590095557e-009

8@gausswin                      9.554773328090960e-006

9@hamming                        2.909805621698069e-005

10@hann                             8.526512829121202e-014         0.06*pi_rad/sample  -100db

11@kaiser                            1.966620797105634e-003

12@nuttallwin                     1.067633093043696e-009

13@Parzenwin                    5.684341886080802e-014    0.12*pi_rad/sample     -120db

14@rectwin                         2.175510504542899e-003

15@triang                           6.978382316447096e-010

16@tukeywin                     1.480771061324049e-011