G.2 Presence of noise reduction

26.1323GPPRelease 18Speech and video telephony terminal acoustic test specificationTS

The intention of this test is to check whether a noise reduction of the electrical interface UE is active or not when a Bluetooth headset or reference interface connects with settings according to Clause G.1.


The noise reduction should not be active for electrical interface UE in this case. The range of attenuation of the simulated background noise should be less than 4 dB, when a simulated background noise is inserted at the send input.

Test Method:

1) The test signal to be used for the measurement shall be pink noise of 20 s duration and calibrated to the default level of -16 dBm0. The noise shall have a bandwidth between 200 Hz to 3.6 kHz for narrowband and 100 Hz to 7 kHz for wideband, super-wideband and fullband mode.

2) The electrical interface is setup as described in clause 5.1.6 and the test signal is transmitted in send direction.

3) The transmitted signal is measured at the output of the system simulator and is referred to the test signal as level versus time analysis according to IEC 61672 [38], using an integration time of 250 ms. The result represents the attenuation of the pink noise (simulated background noise) versus time.

4) The calculated attenuation vs time is corrected by the SJLR measured with the same connection parameters and as specified in clause 7.2.6 for narrowband, 8.2.6 for wideband, 9.2.6 for super-wideband or 10.2.6 for fullband mode.

NOTE: For super-wideband and fullband mode, the bandwidth of the test signal is the same as in wideband, due to current limitations in the Bluetooth connection regarding maximum audio bandwidth. An upper limit of 7 kHz of the pink noise signal is sufficient to accurately evaluate the level analysis. However, this limitation is expected to be resolved by super-wideband capabilities in Bluetooth and the test method might be updated accordingly.