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This topic discusses the standards with which the various acoustic weighting filter VIs comply.

A-, B-, and C-Weighting Filters

Use the SVT A, B, 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.

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:

• ANSI S1.4-1983
• ANSI S1.42-2001

The SVT Weighting Filter VI accommodates any sampling 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.

For all supported sampling rates, the SVT A, B, C Weighting Filter (Fixed Rates) VI achieves Type 0 compliance to the Nyquist frequency.

ISO/IEC and JIS Standards

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, C Weighting Filter (Fixed Rates) VI or designed by the SVT Weighting Filter VI complies with IEC 61672-1:2002 and JIS C 1509-1:2005.

The SVT Weighting Filter VI accommodates any sampling rate greater than 4 kHz and designs the filter coefficients to target the attenuation curves defined by the IEC and JIS 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.

For all supported sampling rates, the SVT A, B, C Weighting Filter (Fixed Rates) VI achieves Class 1 compliance to the Nyquist frequency.

Radiocommunications Weighting Filters

When combined with any DSA device, the weighting filter that the SVT Radiocommunications Weighting Filter (Fixed Rates) VI uses complies with the ITU-R 468-4 standard.

For all supported sampling rates, the SVT Radiocommunications Weighting Filter (Fixed Rates) VI achieves compliance to the Nyquist frequency.

Telecommunications Weighting Filters

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

• ITU-T O.41
• Bell System Technical Reference 41009

For all supported sampling rates, the SVT Telecommunications Weighting Filter (Fixed Rates) VI achieves compliance to the Nyquist frequency.