C.1 Loudness ratings

03.503GPPTransmission planning aspects of the speech service in the GSM Public Land Mobile Network (PLMN) systemTS

C.1.1 Sending Loudness Rating (SLR) – Handset MS

When measured at the DAI:

– the sending sensitivity shall be measured at each of the 14 frequencies given in table 1 of ITU‑T Recommendation P.79, bands 4 – 17;

– the sensitivity is expressed in terms of dBV/Pa and the SLR shall be calculated according to ITU‑T Recommendation P.79 formula 2.1, over bands 4 to 17, and using m = 0,175 and the sending weighting factors from ITU‑T Recommendation P.79 table 1.

Measured at the output of the reference speech decoder of the SS:

– the sending sensitivity from the MRP to the digital output of the reference speech decoder of the SS is determined according to C.3.1;

– the sensitivity is expressed in terms of dBV/Pa and the SLR shall be calculated according to ITU‑T Recommendation P.79 formula 2.1, over bands 4 to 17, and using m = 0,175 and the sending weighting factors from ITU‑T Recommendation P.79 table 1.

C.1.2 Sending Loudness Rating (SLR) – Handsfree MS

– The sending sensitivity from the MRP to the digital output of the reference speech decoder of the SS is determined according to C.3.2.

– The sensitivity is expressed in terms of dBV/Pa and the SLR shall be calculated according to ITU‑T Recommendation P.79 formula 2.1 over bands 4 to 17. The sending weighting factors are given in table 1 of ITU‑T Recommendation P.79 and adjusted according to clause 3 of the same recommendation.

C.1.3 Receiving Loudness Rating (RLR) – Handset MS

When measured from the DAI:

– the receiving sensitivity shall be measured at each of the 14 frequencies listed in table 1 of ITU‑T Recommendation P.79, bands 4 – 17;

– the sensitivity is expressed in terms of dBPa/V and the RLR shall be calculated according to ITU‑T Recommendation P.79 formula 2.1, over bands 4 to 17, using m = 0,175 and the receiving weighting factors from table 1 of ITU‑T Recommendation P.79;

– the artificial ear sensitivity shall be corrected by the LE factor given in table 2 of ITU‑T Recommendation P.79.

Measured from the input of the reference speech encoder of the SS:

– the receiving sensitivity from the analogue or digital input of the reference speech encoder of the SS to the output of the artificial ear is determined according to C.3.3;

– the sensitivity is expressed in terms of dBPa/V and the RLR shall be calculated according to ITU‑T Recommendation P.79 formula 2.1, over bands 4 to 17, using m = 0,175 and the receiving weighting factors from table 1 of ITU‑T Recommendation P.79.

C.1.4 Receiving Loudness Rating (RLR) – Handsfree MS

– The receiving sensitivity from the analogue or digital input of the reference speech encoder of the SS to the output of the measuring microphone (ITU‑T Recommendation P.34; 6.2) or the output of the HATS is determined according to annex C, clause C.3.4. The signals from the two ears of the HATS are combined according to annex B, clause B.4.2.3.2.

– The sensitivity is expressed in terms of dBPa/V and the RLR shall be calculated according to ITU‑T Recommendation P.79 formula 4.19c over bands 4 to 17. The final result is adjusted according to table 3 of the same recommendation to allow for the reduced bandwidth.

– The receiving sensitivity when using the HATS is corrected by 6 dB according to annex B, clause B.4.2.3.2 or when using the measuring microphone it is corrected according to ITU‑T Recommendation P.34.