�1����
Scope
�2���� References
�3���� Definitions and abbreviations
�4���� Convergence Performance of Echo
Cancellers
������� 4.1���� Speech Quality Degradation
Perceived Subjectively
������� 4.2���� Related Objective Parameters for
Single Talk Mode
������� 4.3���� Analysis Methods
����������������� 4.3.1���� Convergence Time (Tc) Test Method
����������������� 4.3.2���� Echo return loss, temporally weighted (ERLtst) � single talk
�5���� Speech Quality Evaluations during
Double Talk
������� 5.1��� �Speech Quality Degradation Perceived Subjectively
������� 5.2���� Related Objective Parameters
������� 5.3���� Analysis Methods
����������������� 5.3.1���� CSS double talk method
����������������� 5.3.2���� Double talk testing using parallel combined sequences
�6���� Companding and AGC Characteristics
������� 6.1���� Speech Quality Degradation
Perceived Subjectively
������� 6.2���� Related Objective Parameter
������� 6.3���� Analysis Methods
�7���� Quality of Background Noise
Transmission
������� 7.1���� Quality Degradation Perceived
Subjectively
������� 7.2���� Related Objective Parameter
������� 7.3���� Analysis Methods
�8���� Switching Characteristics
������� 8.1���� Speech Quality Degradation
Perceived Subjectively
������� 8.2���� Related Objective Parameters
������� 8.3���� Analysis Methods
����������������� 8.3.1���� Attenuation Range and Switching Characteristics
����������������� 8.3.2���� Threshold Level and Build-Up Time (for Minimum Activation Level)
����������������� 8.3.3���� Hangover time
��� ��������������8.3.4���� Threshold Level and Switching Time
to Switch Over from RCV to SND (SND to RCV)
����������������� 8.3.5���� Switching Characteristics in the Presence of Background Noise
Annex A � Detailed
Test Methodology for Temporally Weighted ERLt
������� A.1���� Echo Return Loss Algorithm
����������������� A.1.1���� Echo Return Loss, Temporally Weighted (ERLt)
����������������� A.1.2���� Modelling Echo Audibility
����������������� A.1.3���� Expressing ERLt Results
����������������� A.1.4���� ERLt Test
Algorithm
Annex B � Double talk measurement filters for Method A
Annex C � Training Sequence Description
������� C.1���� Canceller Training prior to Double
Talk
����������������� C.1.1���� Double Talk Training Activity Masks
����������������� C.1.2� ���Synchronizing the Double Talk
Training Activity Masks
����������������� C.1.3���� Compensating for Measurement Filters
Appendix I � Bibliographic references
Appendix II � Example Evaluations
������ II.1���� Some Example Evaluations according
to clause 5
���������������� II.1.1���� Frequency Responses During Double Talk
���������������� II.1.2���� Level Variations During Double Talk
����������������
II.1.3���� Switching During
Double Talk