How to obtain center frequency and its bandwidth of 1/3 Octave filter?

The exact center frequency fm is obtained by the following equation.


fm= Gx/3 *1000
G =103/10 =1.99526
x is any positive, negative, or zero integer.


Example

x=-10  fm =  1.99526-10/3 *1000 = 100
x=-1  fm =  1.99526-1/3 *1000= 794.33
x=0  fm =  1.995260/3 *1000 = 1000
x=1    fm =  1.995261/3 * 1000 = 1258.9
x=5   fm =  1.995265/3 * 1000 = 3162.3
The lower range frequency of each band is obtained.  fL = fm/21/6  
The upper range frequency of each band is obtained.  fU = fm*21/6

fm=1000 fL = 890.9, fU = 1122.46

 

Please refer to “What is sound level meter” in Ono Sokki’s Technical Report.
https://www.onosokki.co.jp/English/hp_e/whats_new/SV_rpt/SV_7/sv7_11.htm#mark11


webinfo





Copyright © ONO SOKKI CO.,LTD All Rights Reserved. | Terms of use | Privacy policy