Appendix F: Miscellaneous

Hamming Window. The hamming window is similar to a hanning window, but it suppresses more the transmissivity for the side lobes next to the transmitting bandwidth. Compared to FFT processing using a hanning window, the degree of separation between two frequencies is greater, as can be seen in Figure F-10. This window is particularly effective for separating close frequencies.

0 dB

3 dB Bandwid h

-20

1.30

-40

Highe￿

 

Side Lobe

-60

-43 dB

Window F!nc ion

F￿eq. Magni !de

Figure F￿10: Hamming Window and Frequency Characteristic

Blackman￿Harris Window. Of the six window functions in this instrument, the Blackman-Harris window has the broadest transmission bandwidth (and therefore, lowest frequency resolution) and the lowest side lobe transmission (and therefore, lowest leakage). This window is particularly suited for observing wide range frequency spectra.

0 dB

3 dB Bandwid h

-20

 

-40

1.66

-60

 

-80

Highe￿

Side Lobe

-100

 

-110

-92 dB

 

Window F!nc ion

F￿eq. Magni !de

Figure F￿11: Blackman￿Harris Window and Frequency Characteristic

AWG2021 User Manual

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