Is often an indication of a leakage problem this can

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Unformatted text preview: nearly perfect FRF measurement results. Note also that in almost every case where high quality FRF measurements have been been achieved, window functions are not required so correction for the window characteristics is unnecessary. (5-62) +UC-SDRL-RJA CN-20-263-663/664 Revision: June 12, 2001 + Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-25. Case 1: Random Excitation with Hann Window Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-26. Case 2: Random Excitation with Hann Window and Cyclic Averaging (5-63) Coherence 0.6 Coherence 0.6 +UC-SDRL-RJA CN-20-263-663/664 Revision: June 12, 2001 + Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-27. Case 3: Burst Random Excitation with Cyclic Averaging Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-28. Case 4: Pseudo Random Excitation (5-64) Coherence 0.6 Coherence 0.6 +UC-SDRL-RJA CN-20-263-663/664 Revision: June 12, 2001 + Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-29. Case 5: Periodic Random Excitation Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-30. Case 6: Pseudo Random Excitation (5-65) Coherence 0.6 Coherence 0.6 +UC-SDRL-RJA CN-20-263-663/664 Revision: June 12, 2001 + Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-31. Case 7: Periodic Random Excitation Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-32. Case 8: Burst Pseudo Random Excitation with Cyclic Averaging (5-66) Coherence 0.6 Coherence 0.6 +UC-SDRL-RJA CN-20-263-663/664 Revision: June 12, 2001 + Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 140 160 180 0 200 Figure 5-33. Case 9: Burst Periodic Random Excitation with Cyclic Averaging Input: 1x Output: 1x Phase (Deg) 180 0 10 0 1 0.9 10 −1 0.8 0.7 Magnitude (g/lb) 10 −2 0.5 0.4 0.3 0.2 0.1 10 −3 10 −4 0 20 40 60 80 100 120 Frequency (Hertz) 1...
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This note was uploaded on 09/29/2013 for the course MECHANICAL ME taught by Professor Regalla during the Fall '11 term at Birla Institute of Technology & Science, Pilani - Hyderabad.

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