CS-122278-UGP1 Cambridge Silicon Radio Limited 2008 This material is subject to CSRs non-disclosure agreement. CSR Cambridge Science Park Milton Road Cambridge CB4 0WH United Kingdom Registered in England 3665875 Tel: +44 (0)1223 692000 Fax: +44 (0)1223 692001 www.csr.com =s=s= cVc 2 Mic Headset Tuning Guide Product Code: BCSW-CVC-HS-5-2-1 Issue 1 Contents CS-122278-UGP1 Cambridge Silicon Radio Limited 2008 This material is subject to CSRs non-disclosure agreement. Page 2 of 35 =s=s= =s=ep=eJO=q=d=s=ep=eJO=q=d= Contents 1 Introduction4 1.1 General4 1.2 Before You Begin 4 2 Prerequisites5 2.1 Parameter Manager Tool and User Guide.5 2.2 SPI Communication Protocol Drivers 7 2.3 Hardware Interfaces 7 3 Tuning Overview8 4 Tuning Preparation10 4.1 Before You Begin 10 4.2 Headsets .10 4.3 Phone Models and Network Types10 4.4 Tuning Environment 11 4.5 Level Speech Phrase 11 5 Instrumentation12 5.1 SPL Meter12 5.2 Head and Torso Simulator.12 6 Tuning Procedures 13 6.1 Objective Measurement.13 6.2 Receive Path Tuning .13 6.2.1 Load Preset Parameters 13 6.2.2 Receive AGC .14 6.2.3 SPKR Gain.14 6.2.4 Noise Dependent Volume Control15 6.3 Send Path Tuning16 6.3.1 MIC Gain16 6.3.2 Send AGC17 6.3.3 Noise Suppression.18 6.3.4 Comfort Noise18 7 Fine Tuning.19 7.1 Receive Path.19 7.1.1 Setting Minimum Loudness19 7.1.2 Receive AGC .19 7.1.3 Receive EQ19 7.1.4 Clipper20 7.1.5 Auxiliary Stream Mix 20 7.1.6 Side Tone.20 7.2 Send Path21 7.2.1 MIC Gain in NS Mode21 7.2.2 Acoustic Echo Canceller 21 7.2.3 Send EQ 22 7.2.4 Send AGC23 7.2.5 Noise Suppression.23 8 Tuning Preparation Checklist .24 9 Flowcharts25 9.1 cVc HS Tuning Overview.25 9.2 SPKR Gain26 9.3 MIC Gain .27 9.4 NDVC (Part 1 of 2) 28 9.5 Noise Suppression 30 Contents CS-122278-UGP1 Cambridge Silicon Radio Limited 2008 This material is subject to CSRs non-disclosure agreement. Page 3 of 35 =s=s= =s=ep=eJO=q=d=s=ep=eJO=q=d= 9.6 Send Path Output Level (Send AGC Target Level) .31 9.7 Comfort Noise32 10 Document References.33 Terms and Definitions 34 Document History.35 Document Feedback.35 List of Figures Figure 2.1 Accessing Headset Parameter Manager from UFE .5 Figure 2.2 Parameter Manager Window .6 Figure 2.3 CSR SDK Software Setup Window with Driver Installation Option Selected7 Figure 3.1 cVc HS Overview in the Parameter Manager.8 Figure 3.2 The Five cVc HS Tuning Stages8 Figure 4.1 A Recorded Waveform of the English Phrase “one two three four five”.11 Figure 6.1 Receive Path Processing Blocks .13 Figure 6.2 Send Path Processing Block Diagram .16 Figure 7.1 Low Volume Mode Threshold Operation22 Introduction CS-122278-UGP1 Cambridge Silicon Radio Limited 2008 This material is subject to CSRs non-disclosure agreement. Page 4 of 35 =s=s= =s=ep=eJO=q=d=s=ep=eJO=q=d= 1 Introduction This document is designed for audio developers and describes how to tune clear Voice capture (s ) 2 mic Headset (HS) audio processing software running on BlueCore-Multimedia Integrated Circuits (IC). A Windows PC-based configuration tool (Parameter Manager) that communicates with CSRs Bluecore IC, simplifies the tuning process. This tool monitors audio signal statistics and can be used to adjust cVc HS audio processing block parameters to achieve optimal audio performance. 1.1 General cVc software is a sophisticated application that allows users to compensate for environmental and acoustic variables to improve a products sound quality performance. The cVc software tuning procedure is completed by a series of acoustic and electro-acoustic tests and measurements performed in a specific sequence. The test results are used to modify cVc software audio processing parameters. The main purpose of the cVc software tuning procedure is to achieve an optimum level of headset sound quality. The product developer may perform the cVc tuning process at several stages during the headset systems development cycle. Typically, a developer fabricates a prototype headset system that packages audio, power, communication, and processing components. Tuning can begin when a prototype system is available. Final tuning to verify optimal performance should be completed when the final production components and packaging are available. The cVc HS application includes default settings that can be used for its audio processing. These defaults may require gains tweaking to compensate for variations in the hardware design, such as microphones and speakers. 1.2 Before You Begin CSR recommends that product developers become familiar with the principles of acoustic performance and the tuneable parameters supported by the Parameter Manager tool. Section 9 provides flowcharts to help speed up the familiarisation process. Prerequisites CS-122278-UGP