Frequency weighting

The program signals filtration includes the following filters with frequency weighting functions:

Wb, Wc, Wd, We, Wf, Wh, Wj, Wk, Wm, Fh, Fk, Fm, A, B, C, D.

Frequency weighting W

The program Signals filtration has filters with frequency weighting options Wb, Wc, Wd, We, Wf, Wh, Wj, Wk, Wm meeting the requirements of the applicable international standards including IEC 61672-1: 2002 (Electroacoustics – Sound level measurements – Part 1: Specifications).

Frequency weighting function	0 APPLICATION 0	Nominal frequency range, Hz	Reference frequency, rad/s (Hz)	Value of frequency weighting function at the reference frequency
Wh	Frequency weighting function Wh for measurement of local vibration in all directions (in compliance with ISO 5349-1)	8…1000	500 (79,58)	0,2020
Wb	Frequency weighting function Wb for measurement of general vibration in vertical direction (axis z), for vibration impact in seated, standing, and recumbent position (in compliance with ISO 2631-4)	0,5…80	100 (15,915)	0,8126
Wc	Frequency weighting function Wc for measurement of general vibration in horizontal direction (axis х), for vibration impact in seated position, seat surface (in compliance with ISO 2631-1)	0,5…80	100 (15,915)	0,5145
Wd	Frequency weighting function Wd for measurement of general vibration in horizontal position (axis х or у), for vibration impact in seated, standing or recumbent position (in compliance with ISO 2631-1)	0,5…80	100 (15,915)	0,1261
We	Frequency weighting function We for measurement of common angular vibration in all directions, for vibration impact in standing position (in compliance with ISO 2631-1)	0,5…80	100 (15,915)	0,06287
Wj	Frequency weighting function Wj for measurement of vibration in vertical direction (axis х), vertical recumbent (head) (in compliance with ISO 2631-1)	0,5…80	100 (15,915)	1,019
Wk	Frequency weighting function Wk for measurement of common vibration in vertical direction (axis z), for vibration impact in seated, standing and recumbent position (in compliance with ISO 2631-1)	0,5…80	100 (15,915)	0,7718
Wm	Frequency weighting function Wm for measurement of common vibration inside of buildings in all directions (in compliance with ISO 2631-2)	1…80	100 (15,915)	0,3362
Wf	Frequency weighting function Wf for measurement of general low-frequency vibration in vertical direction (axis z), for vibration impact in seated or recumbent position (in compliance with ISO 2631-1)	0,1…0,5	2,5 (0,3979)	0,3888

Frequency weighting function Wm

Frequency weighting function Wh

Frequency weighting function Wd

Frequency weighting function Wk

Frequency weighting function Wf

Frequency weighting function Wc

Frequency weighting function Wj

Frequency weighting function We

Frequency weighting function Wb

Linear filters

The program Signal filtration includes the following linear filters with frequency weighting options:

Fh — linear band-pass filter 6,8…1286 Hz,
Fk — linear band-pass filter 0,4…100 Hz,
Fm — linear band-pass filter 0,8…100 Hz

The results of filters implementation (signal spectra processed by frequency weighting filters Fh, Fk, Fm) are shown below:

Frequency weighting Fh

Frequency weighting Fk

Frequency weighting Fm

Compensating filters А, В, С and D

The filters with frequency weighting functions A, B, C, and D are used for noise level measurements and meet the requirements of the applicable standards. Implementation of the filters allows to use FFT Spectrum analyzers ZET 017-U2, ZET 017-U8 and A19-U2 as high-precision noise level meters.

The figures below show signals spectra that have been processed by frequency weighting functions A, B, C and D, implemented in the program Signals filtration.