Building Acoustics

20 Building acoustics 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 Timet(s) -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2 ...

Oscillating systems 21 time T. In the same way as when applying the fixed filter analysis, outlined in section 1.4.5.1, we have ...

22 Building acoustics 0 100 200 300 400 500 Frequency (Hz) 1E-006 1E-005 1E-004 1E-003 1E-002 G (f ), relative values n = 5 n = ...

Oscillating systems 23 1.5.1 Probability density function. Autocorrelation In Figure 1.2, the probability distribution was liste ...

24 Building acoustics to the maximum values. This is easily seen looking at a sinusoidal function. The function “spends more tim ...

Oscillating systems 25 than the mean square value of the signal. Lastly, the value of the function will, for stochastic signals, ...

26 Building acoustics called chirp or sinusoidal sweep to give some names found in the literature. This is a signal where the fr ...

Oscillating systems 27 a) (^00100200300400500) 10 20 30 40 50 60 Frequency (Hz) |X(f)| b) (^00100200300400500) 5 10 15 20 25 30 ...

28 Building acoustics The literature on MLS is relatively large but for a discussion of basic properties one may look at the art ...

Oscillating systems 29 above, this may be a serious limitation in using MLS as opposed to the swept sine technique. 0 5 10 15 20 ...

30 Building acoustics 1.6 References IEC 61260: 1995, Electroacoustics − Octave band filters and fractional-octave band filters. ...

CHAPTER 2 Excitation and response of dynamic systems 2.1 INTRODUCTION The main purpose of Chapter 1 was to give a general descri ...

32 Building acoustics assume that our physical system is linear within a certain magnitude range of excitation. This applies to ...

Excitation and response 33 we must be able to calculate these functions, analytically, numerically or by using empirical methods ...

34 Building acoustics A description giving the relationship between the input and output in the time domain is also appropriate. ...

Excitation and response 35 2 GHfGyy= ()⋅ xx (2.4) and GHfGxy=⋅( ) xx. (2.5) The first equation links together the power spectrum ...

36 Building acoustics easily and accurately determine impulse responses for a system and thereby one may determine the correspon ...

Excitation and response 37 of transfer functions we shall use and many of these functions have special names. In this chapter, w ...

38 Building acoustics Table 2.1 Impedance and mobility of the simple elements mass, spring and viscous damper. F – force, v – ve ...

Excitation and response 39 When depicting an impedance or mobility in a frequency diagram one usually uses a logarithmic scale a ...