03.503GPPTransmission planning aspects of the speech service in the GSM Public Land Mobile Network (PLMN) systemTS
With the handset mounted at LRGP and the earpiece sealed to the knife‑edge of the artificial ear in a quiet environment (ambient noise less than 30 dBA), the noise level at the digital output is measured with apparatus including psophometric weighting according to ITU‑T Recommendation G.223, table 4.
NOTE: The ambient noise criterion should be met if the ambient noise does not exceed NR20.
The handset is mounted at LRGP and the earpiece is sealed to the knife‑edge of the artificial ear. A signal corresponding to decoder output value number 1 shall be applied at the digital interface. The level of the noise shall be measured at the ERP.
The ambient noise for this measurement shall not exceed 30 dBA.