6 Precise Frequency Domain Algorithm of Half Spectrum and FRF 69 0 0 200 400 600 800 1k 1200(Hz) FRF(H1) SF= 12800.000Hz Ave. times: 4 Df= 3.1250Hz Tot points: 401 cursor: 108 H = 2.9126e+001 Ph.= 91.026 Co.= 1.000 NewCo.= 1.000 FitIndex=98.605% m/s2/N f = 334.3750Hz 0.25 0.5 0.75 1.0 -180 -90 0 90 180 0 0.50 1 1.50 2 2.50 3 3.50 (e+1)m/s2/N Name:test Test No.:1 Input:f1 Output:1 Fig. 6.13 FRF and new coherence function with five times averaging References 1. Pierro E, Mucchi E, Soria L, Vecchio A (2009) On the vibro-acoustical operational modal analysis of a helicopter cabin. Mech Syst Signal Pr 23(4):1205–1217 2. Chen PQ (2004) Digital signal processing tutorial. Tsinghua University Publishing Company, Beijing, pp 104–108 3. Liu JM, Zhu WD, Lu QH, Ren GX (2011) An efficient iterative algorithm for accurately calculating impulse response functions in modal testing. J Vib Acoust 133(6). doi: 10.1115/1.4005221 4. Fladung W, Rost R (1997) Application and correction of the exponential window for frequency response functions. Mech Syst Signal Pr 11(1):23–36 5. Liu JM, Zhu WD, Ying M, Shen S (2013) Fast precise algorithm of computing FRF by considering initial response. Proceedings of the SEM IMAC XXXI Conference, Los Angeles, CA 6. Zhang GY, Liu JM (2008) Measurement of Lupu arch bridge vibration characteristics. J Vib Shock (China) 27(9):167–170
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