03.503GPPTransmission planning aspects of the speech service in the GSM Public Land Mobile Network (PLMN) systemTS
The handset is mounted at LRGP and the earpiece is sealed to the knife‑edge of the artificial ear. An instrument capable of measuring the third harmonic distortion of signals with fundamental frequencies in the range of 315 Hz to 1 kHz is connected to the artificial ear.
A pure‑tone signal of –4,7 dBPa is applied at the mouth reference point at frequencies of 315 Hz, 500 Hz, and 1 kHz. For each frequency, the third harmonic distortion shall be measured at the ERP.