### 1. Overview of Standards

**Weighting Filters**

#### A-, B-, and C-Weighting Filters

- ANSI S1.4-2014
- ANSI S1.42-2001
- IEC 61672-1:2013
- JIS C 1509-1:2005

#### Weighting Filters

- ITU-R 468-4
- JIS C 6102:1998
- Dolby

#### Telecommunications Weighting Filters

- ITU-T 0.41 (CCITT)
- Bell System Technical Reference 41009 (C-message)

#### Human Vibration Weighting Filters

- ISO 8041:2005 (E): Human Response to Vibration – Measuring Instrumentation
- JIS B 7760:2004: Whole-Body Vibration
- JIS B 7761:2004: Hand-Transmitted Vibration

**Octave Analysis**

- ANSI S1.11-2014: Electroacoustics - Octave-band and fractional-octave-band filters, class 1
- IEC 61260:2014: Electroacoustics - Octave-band and fractional-octave-band filters, class 1
- JIS C 1514:2002: Electroacoustics - Octave-band and fractional-octave-band filters, class 1

**Sound Level**

- ISO/IEC 61672-1:2002
- ANSI S1.4-1983

### 2. Weighting Filters

### A-, B-, and C-Weighting Filters

#### ANSI Standards

When combined with any DSA device, the weighting filter used by the SVT A, B, C Weighting Filter (Fixed Rates) VI or designed by the SVT Weighting Filter VI complies with the following standards:

The SVT Weighting Filter VI accommodates any sample rate greater than 4 kHz and designs the filter coefficients to target the attenuation curves defined by the ANSI standards. Given the selected sampling frequency, compliance with a particular filter type, either Type 1 or Type 0, is ensured up to a specific frequency. This frequency is the maximum frequency within tolerances. Use the SVT Max Frequency Within Tolerances [ANSI] VI to determine the maximum frequency within tolerances. The SVT A, B, C Weighting Filter (Fixed Rates) VI supports the following sample rates:

4 kHz, 8 kHz, 10 kHz, 11.025 kHz, 12.8 kHz, 20 kHz, 22.05 kHz, 25.6 kHz, 40 kHz, 44.1 kHz, 48 kHz, 50 kHz, 51.2 kHz, 80 kHz, 96 kHz, 100 kHz, 102.4 kHz, 192 kHz, 200 kHz, 204.8 kHz, 500 kHz, 1 MHz

For all supported sample rates the VI achieves Type 0 compliance to the Nyquist frequency.

#### ISO/IEC Standard

Use the SVT A, B, or C Weighting Filter (Fixed Rates) VI or the SVT Weighting Filter VI to apply an A-, B-, or C-weighting filter to time-domain signals. When combined with any DSA device, the weighting filter used by the SVT A, B, or C Weighting Filter (Fixed Rates) VI or designed by the SVT Weighting Filter VI complies with:

- IEC 61672-1:2002

The SVT Weighting Filter VI accommodates any sample rate greater than 4 kHz and designs the filter coefficients to target the attenuation curves defined by the IEC standards. Given the selected sampling frequency, compliance with a particular filter type, either Class 2 or Class 1, is ensured up to a specific frequency. This frequency is the maximum frequency within tolerances. Use the SVT Max Frequency Within Tolerances [IEC] VI to determine the maximum frequency within tolerances. The SVT A, B, C Weighting Filter (Fixed Rates) VI supports the following sample rates:

4 kHz, 8 kHz, 10 kHz, 11.025 kHz, 12.8 kHz, 20 kHz, 22.05 kHz, 25.6 kHz, 40 kHz, 44.1 kHz, 48 kHz, 50 kHz, 51.2 kHz, 80 kHz, 96 kHz, 100 kHz, 102.4 kHz, 192 kHz, 200 kHz, 204.8 kHz, 500 kHz, 1 MHz

For all supported sample rates the VI achieves Class 1 compliance to the Nyquist frequency.

### Radiocommunications Weighting Filters

#### ITU-R 468-4 and Dolby

When combined with any DSA device, the weighting filter used by the SVT Radiocommunications Weighting Filter (Fixed Rates) VI complies with the ITU-R 468-4 standard. The SVT Radiocommunications Weighting Filter (Fixed Rates) VI accommodates the following sample rates:

20 kHz, 22.05 kHz, 25.6 kHz, 40 kHz, 44.1 kHz, 48 kHz, 50 kHz, 51.2 kHz, 80 kHz, 96 kHz, 100 kHz, 102.4 kHz, 192 kHz, 200 kHz, 204.8 kHz, 500 kHz, 1 MHz

For all supported sample rates, the VI achieves compliance to the Nyquist frequency.

### Telecommunications Weighting Filters

When combined with any DSA device, the weighting filter used by the SVT Telecommunications Weighting Filter (Fixed Rates) VI complies with the following standard and reference:

- ITU-T 0.41 (CCITT)
- Bell System Technical Reference 41009 (C-message)

The SVT Telecommunications Weighting Filter (Fixed Rates) VI supports the following sample rates:

4 kHz, 8 kHz, 10 kHz, 11.025 kHz, 12.8 kHz, 20 kHz, 22.05 kHz, 25.6 kHz, 40 kHz, 44.1 kHz, 48 kHz, 50 kHz, 51.2 kHz, 80 kHz, 96 kHz, 100 kHz, 102.4 kHz, 192 kHz, 200 kHz, 204.8 kHz, 500 kHz, 1 MHz

For all supported sample rates, the VI achieves compliance to the Nyquist frequency.

### Human Vibration Weighting Filters

When combined with any DSA device, the human vibration weighting filters that the Sound and Vibration Measurement Suite provides comply with ISO 8041:2005 (E): Human Response to Vibration – Measuring Instrumentation.

The Sound and Vibration Measurement Suite provides the following weighting filters that you can apply to human vibration signals:

- Wb—Weighting for vertical whole-body vibration, z–axis, seated, standing or recumbent person, based on ISO 2631–4.
- Wc—Weighting for horizontal whole-body vibration, x–axis, seat back, seated person, based on ISO 2631-1.
- Wd—Weighting for horizontal whole-body vibration, x– or y–axis, seated, standing or recumbent person, based on ISO 2631-1.
- We—Weighting for rotational whole-body vibration, all directions, seated person, based on ISO 2631-1.
- Wf—Weighting for vertical whole-body vibration, z–axis motion sickness, seated or standing person, based on ISO 2631-1.
- Wh—Weighting for hand-arm vibration, all directions, based on ISO 5349-1.
- Wj—Weighting for vertical head vibration, x–axis recumbent person, based on ISO 2631-1.
- Wk—Weighting for vertical whole-body vibration, z–axis seated, standing or recumbent person, based on ISO 2631-1.
- Wm—Weighting for whole-body vibration in buildings, all directions, based on ISO 2631-2.

### 3. Octave Analysis

### Overview

The Octave Analysis VIs can accommodate any sampling frequency and any number of fractional-octave bands. These VIs offer compliance with the following standards:

- ANSI S1.11-2014: Electroacoustics - Octave-band and fractional-octave-band filters, class 1
- IEC 61260:2014: Electroacoustics - Octave-band and fractional-octave-band filters, class 1

### Midband Frequencies

According to the IEC 61260:2014 and the ANSI S1.11-2014 standards, the exact mid-band frequencies, fm, of any filter in a set of filters shall be determined from the following expression:

* f*_{m} = *f*_{r}*G ^{x}*

^{/b}, when

*b*is odd

* f*_{m} = *f*_{r}*G*^{(2x }+ 1)/2*b*, when *b* is even

Where *f*_{r} is the reference frequency, *G* = 10^{0.3} is the octave frequency ratio, 1/*b* is the bandwidth designator, and equals 1 for octave, 1/3 for 1/3 octave, 1/6 for 1/6 octave, 1/12 for 1/12 octave, and 1/24 for 1/24 octave, *x* is any integer, positive or negative, or zero.

### Nominal Frequencies

The exact midband frequencies are used to design the filters for fractional-octave analysis. However, all the octave analysis tools in the Sound and Vibration Measurement Suite return the nominal midband frequencies, also called the preferred frequencies. In the case of octave and 1/3 octave analyses, the nominal frequencies are calculated in accordance with the ANSI and IEC standards. In the case of 1/6, 1/12, and 1/24 octave analyses, the nominal frequencies are calculated in accordance with the Annex E (informative) of the IEC 61260:2014 and the ANSI S1.11-2014 standards.

### Compliance with ANSI and IEC Standards

When combined with any National Instruments DSA device, the appropriate microphone, and proper signal conditioning, the filters produced by the octave analysis tools in the Sound and Vibration Measurement Suite comply with the following standards:

- ANSI S1.11-2014: Electroacoustics - Octave-band and fractional-octave-band filters, class 1
- IEC 61260:2014: Electroacoustics - Octave-band and fractional-octave-band filters, class 1
- JIS C 1514:2002: Electroacoustics - Octave-band and fractional-octave-band filters, class 1

For octave filters, choose a sampling frequency at least three times the exact center frequency of the highest frequency band. For fractional-octave filters, choose a sampling frequency at least 2.5 times the exact center frequency of the highest frequency band.

### 4. Sound Level

When combined with any National Instruments DSA device, the appropriate microphone, and proper signal conditioning, the Sound Level VIs are compliant with the ISO/IEC 61672-1:2002 standard.

National Instruments dynamic signal acquisition boards combined with the NI LabVIEW Sound and Vibration Software, have been tested and found compliant with several ANSI and IEC standards including the requirements for a class 1 instrument specified in IEC 61672-1: 2002. The filters used meet the requirements for a class 1 instrument specified in IEC 61260: 1995.

For a complete system, a suitable microphone compatible with ANSI S1.4 or IEC 651 requirements for a Type 1 precision microphone needs to be specified.