5.1.4 Position and calibration of HATS

26.1323GPPRelease 18Speech and video telephony terminal acoustic test specificationTS

The horizontal positioning of the HATS reference plane shall be guaranteed within  2° for testing hands-free equipment.

The HATS shall be equipped with a Type 3.3 Artificial Ear. For hands-free measurements the HATS shall be equipped with two artificial ears. The pinnae are specified in Recommendation P.57 [14] for Type 3.3 artificial ears. The pinnae shall be positioned on HATS according to ITU-T Recommendation P.58 [15].

The exact calibration and equalization procedures as well as how to combine the two ear signals for the purpose of measurements can be found in ITU-T Recommendation P.581.

If not stated otherwise, the HATS shall be diffuse-field equalized using values from ITU-T Recommendation P.58 [15]. For 1/3-octave band measurements, the inverse of the nominal diffuse field curve in P.58 table 3 shall be used. For 1/12-octave band measurements, the inverse of the nominal diffuse field curve in P.58 Annex A shall be used. For measurements requiring diffuse-field correction values for frequencies other than those used in the P.58 tables, linear interpolation on a log frequency scale from the P.58 Annex A values shall be used.

For hand-held hands-free UE, the setup corresponding to ‘portable hands-free’ in ITU-T Recommendation P.581 should be used.