Table of Contents

�1���� Scope����������
�2���� References
�3���� Definitions�
�4���� Abbreviations and acronyms�������������
�5���� Conventions�������������
�6���� How to use this Recommendation��
�7���� Architectures�����������
������� 7.1���� Distributed speakerphone�������
������� 7.2���� System with integrated microphone���
������� 7.3���� System with integrated speaker�����������
������� 7.4���� System with integrated microphone and speaker���������
�8���� Subsystems��������������
������� 8.1���� System delay, subsystem delay and buffering
������� 8.2���� Test interface description��������
������� 8.3���� Acoustic subsystem����
������� 8.4���� Signal enhancement subsystem������������
�9���� Bidirectional signal transport including network transport����
������� 9.1���� Bidirectional transport delay in send direction
������� 9.2���� Clock drift in send direction�����
������� 9.3���� Bidirectional transport delay in receive direction�����������
������� 9.4���� Clock drift in receive direction
������� 9.5���� Bidirectional transport send junction loudness ratings
������� 9.6���� Bidirectional transport receive loudness ratings�������������
������� 9.7���� Bidirectional transport linearity in send direction�����������
������� 9.8���� Bidirectional transport linearity in receive direction������
������� 9.9���� Bidirectional transport send sensitivity frequency response�����
������ 9.10���� Bidirectional transport receive sensitivity frequency response��������������
������ 9.11���� Bidirectional transport idle channel noise in send���������
������ 9.12���� Bidirectional transport idle channel noise in receive����
������ 9.13���� Bidirectional transport noise cancellation test in send direction�������������
������ 9.14���� Bidirectional transport one‑way speech quality in send direction����������
������ 9.15���� Bidirectional transport speech quality stability in send direction������������
������ 9.16���� Bidirectional transport one‑way speech quality in receive direction�����
������ 9.17���� Bidirectional transport speech quality stability in receive direction�������
������ 9.18���� Verification of bidirectional transport disabled echo control����
������ 9.19���� Bidirectional transport subsystem weighted terminal coupling loss (TCLw_BD) and (TCL_BD)����
10���� Unidirectional signal transport: Wired and short range wireless transmission�������������
������ 10.1���� Test set-up����
������ 10.2���� Unidirectional transport delay��������������
������ 10.3���� Unidirectional clock drift����������
������ 10.4���� Unidirectional transport junction loudness ratings�������
������ 10.5���� Unidirectional transport linearity���������
������ 10.6���� Unidirectional transport sensitivity frequency response�����������
������ 10.7���� Unidirectional transport idle channel noise�����
������ 10.8 ����Unidirectional transport noise cancellation test������������
������ 10.9���� Unidirectional transport speech quality������������
����� 10.10���� Unidirectional transport speech quality stability����������
Annex A � Microphone measurements in anechoic conditions����
������� A.1���� Microphone sensitivity (in anechoic conditions)������������
������� A.2���� Microphone frequency response (in anechoic conditions)�������
������� A.3���� Microphone directional characteristics (in anechoic conditions)�������������
������� A.4���� Microphone distortion (in anechoic conditions)�������������
������� A.5���� Microphone maximum sound pressure level (in anechoic conditions)�
������� A.6���� Microphone dynamic range (in anechoic conditions)���
Annex B � Standard set of user scenarios����
Annex C � Frame process and delay����
������� C.1 ����General�����������
������� C.2���� Frame interval��������������
������� C.3���� Delay
������� C.4���� Arbitration between two subsystems with different frame intervals���
������� C.5���� Subsystem delay and relationship to overall delay��������
������� C.6���� Example����������
Appendix I � Testing for Noise Distortion����
������� I.1���� Parameter description
������� I.2���� Test����
������� I.3���� Classification of performance level based on values of this parameter�
������� I.4���� Design guidance and root-cause analysis������������
Appendix II � Reference-free SNR measurement����
������ II.1���� Introduction���
������ II.2���� Signal-to-noise ratio measurement������
������ II.3���� Noise variance tracking and voice activity detection������
������ II.4���� Speech pause detection������������
������ II.5���� Measurement set-up�
Appendix III � Measuring and applying impulse response traces for dynamic test conditions����
����� III.1���� Introduction���
����� Page
����� III.2���� Excitation signal������������
����� III.3���� Measurement Set-up
����� III.4���� System model
����� III.5��� �Signal convolution��������
Bibliography����