Hi,

The RMS value is obtained from Time domain Data, but in order to evaluate the Human vibration, according to ISO 5349 (Hand-Arm) and ISO 2631 (Whole Body), after obtaining Frequency Domain you should calculate the weighted vibrations in1/3rd Octave bands. 

I used this following table based on mentioned standars (attached Figure)

based on this figure, for example when you are going to evaluate vibration in center frequency of 1 Hz, you calculate the RMS of vibration in narrow band frequency in 0.89-1.12 Hz and multiply it to 0.482  in the z direction. for other center frequencies in 1/3rd octave use the same method (f1 is lower band, f2 upper band). 

follow the link...a matlab code for analysis

Follow the link...consists of matlab code

https://in.mathworks.com/matlabcentral/fileexchange/21384-continuous-sound-and-vibration-analysis?requestedDomain=www.mathworks.com

may be conformed by SAS analysis

Hossein Ahmadian Could u plz provide the reference of above chart.

Refer ISO 2631for Whole Body and ISO 5349 for Hand-Arm.

Dear Ertuğrul Bilgin,

Octave bands can be separated into three ranges - referred to as one-third-octave bands. An octave band is a frequency band where the highest frequency is twice the lowest frequency. For example, an octave filter with a centre frequency of 1kHz has a lower frequency of 707Hz and an upper frequency of 1.414kHz. Real-time analyzers or octave-band analyzers are special sound level meters that divide noise into its frequency components. Electronic filter circuits are used to divide the sound or noise into individual frequency bands. A band is said to be an octave in width when the upper band frequency is twice the lower band frequency.

A one-third octave band is defined as a frequency band whose upper band-edge frequency (f2) is the lower band frequency (f1) times the cube root of two.

Example, 55 Hz and 440 Hz are one and two octaves away from 110 Hz because they are ​ 1⁄2 (or ) and 4 (or ) times the frequency, respectively. The octave is defined by ANSI as the unit of frequency level when the base of the logarithm is two.

Octave calculation

If {\displaystyle f_{c}}fc is the center frequency of an octave band, one can compute the octave band boundaries as

fc = √2 fmin= fmax/ √2

Where {\displaystyle f_{min}}fmin is the lower frequency boundary and {\displaystyle f_{max}}fmax the upper one.

One third octave calculation

Base 2 calculation

%% Calculate Third Octave Bands (base 2) in Matlab

fcentre = 10^3 * (2 .^ ([-18:13]/3))

fd = 2^(1/6);

fupper = fcentre * fd

flower = fcentre / fd

Base 10 calculation

%% Calculate Third Octave Bands (base 10) in Matlab

fcentre = 10.^(0.1.*[12:43])

fd = 10^0.05;

fupper = fcentre * fd

flower = fcentre / fd

References:

"ANSI S1.11: Specification for Octave, Half-Octave, and Third Octave Band Filter Sets" (PDF). Retrieved 7 March 2018.

Ashish