原标题：基于Qualcomm CSR8675 Broadcast Audio一对多喇叭方案

　　在2017年第三季之前，蓝牙喇叭都还是一直最多只能同时支持两个蓝牙喇叭来播放音乐。但由于市场对于音乐同时分享到多个蓝牙喇叭的应用询问度增加。Qualcomm在2017第四季就改变了一个新的蓝牙喇叭应用，它利用Broadcast Audio技术实现音乐可同时分享给数个蓝牙喇叭。

　　Broadcast Audio这项技术改变了大家对传统蓝牙喇叭的使用，更增加了蓝牙喇叭在日常生活上的应用。好比，想在家里和好朋友办音乐派对，但又担心会影响左邻右舍的安宁，就可将Broadcast Audio技术应用到蓝牙耳机，每位贵宾可透过自己蓝牙耳机和与会朋友一起尽情享受音乐又不会干扰左邻右舍。在户外派对上又可透过Broadcast Audio结合所有好友的蓝牙喇叭，把会场气氛炒翻天。

　　Broadcast Audio技术除了在派对上的使用情境外，透过各界不同需求，相信一定还会有更多的应用产生。

　　场景应用图

　　展示板照片

　　方案方块图

　　核心技术优势

　　1. 透过蓝牙的双模技术，利用BLE (GATT)绑定所有蓝牙喇叭或耳机。

　　2. 声音数据(CELT)透过广播模式(CSB)传送到每一个蓝牙喇叭或耳机。

　　3. 一个Broadcaster可以同时传送给无上限个Receiver。

　　4. 每一个蓝牙喇叭都可以当Broadcaster或Receiver角色，但不能同时扮演Broadcaster和Receiver角色。

　　方案规格

　　1. Full audio input routing. In the Receiver mode, the broadcast input has lowest priority by default.

　　2. HFP support in Broadcaster and Receiver. Broadcast Audio is stopped while in HFP call.

　　3. I2S output sample rate (44.1 kHz or 48 kHz) can be selected independently from the input sample rate.

　　4. Mute. When mute is applied in the Broadcast mode silence is broadcasted.

　　5. DSP volume API is the same as in the standard Speaker. When switching between the standard Speaker and broadcast modes output signal level do not change.

　　6. Bluetooth low energy technology.

　　7. Over-The-Air Upgrade.

　　【CSR8675】

技术文档：

csr8675-product-brief.pdf

　　CSR8675 Bluetooth Audio SoC

　　Embedded Flash Solution for Premium Bluetooth Audio Applications

　　CSR8675 is a premium tier single-chip solution delivering high quality wireless audio performance and supporting the development of highly differentiated premium wireless audio products. Integrated support for aptX, aptX HD, Active Noise Cancellation and Qualcomm TrueWireless stereo.

　　Specifications

　　Bluetooth

　　Bluetooth Version: Bluetooth 5.0

　　Bluetooth Radio: +10dBm maximum output power (typical), -90dBm receiver sensitivity (basic rate, typical)

　　USB

　　USB Support: Supports USB charger detection

　　USB Version: USB 2.0 (Full Speed)

　　General Audio

　　Audio Technology: Qualcomm TrueWireless™ Technology, Qualcomm® Broadcast Audio technology, Qualcomm® aptX™ audio technology, Qualcomm® cVc™ audio technology, 24 bit audio data path

　　Qualcomm® aptX™ playback support: aptX Classic, aptX HD, Qualcomm® eXtension program

　　Analog Microphone Input: 2 analog mics/line inputs (up to 96kHz sample rate)

　　Digital Microphone Input: 6 digital mics

　　Analog DAC output: 2 analog DAC channels (up to 192kHz sample rate)

　　Microphone Bias Generator: 2 microphone bias generators

　　DSP

　　DSP Technology: Qualcomm® Kalimba™ DSP

　　DSP Clock Speed: 80 MHz

　　Charging

　　Maximum Current: 200 mA on chip, 500 mA with external transistor

　　Memory

　　Flash: 16 Mb internal flash, Up to 64 Mb external flash

　　Interface

　　Supported Interfaces: Master I²C, 2x PCM/I²S, 2x SPDIF, UART

　　Input/Output

　　ADC: 2 ADCs

　　General Purpose IOs: 32

　　DAC: 2 DACs

　　PWM (LED): 3

　　Input

　　Touch Sensor Inputs: 6 touch sensor inputs

　　Package

　　Package Type: VFBGA, WLCSP, 4.8 x 4.8 x 0.6 mm 0.5 mm pitch WLCSP, 6.5 x 6.5 x 1 mm 0.5 mm pitch VFBGA

　　Pitch: 0.5mm Pitch

　　CSR8675 is a premium tier single-chipsolution in our CSR86xx Bluetooth audioSoC portfolio designed to deliver highquality wireless audio performance andsupportdevelopment of highly differentiatedpremium wireless audio products.

　　CSR8675 is part of the CSR86xx portfolio,a range of silicon platforms for wirelessaudio applications which integrate a dualmodeBluetooth radio, a low power DSP, an application processor, a battery charger,memory and various audio and hardware interfaces into a single-chip solution.

　　The CSR8675 SoC also integrates a dedicated active noise cancellation* block for earbud and headphone applications, and a 120Mhz Qualcomm® Kalimba™ DSP, which allows support for 24-bit audio over Bluetooth and aptX HD making it an ideal choice for premium audio products.

　　There is comprehensive Audio Development Kit (ADK) software for CSR8675 which includes Bluetooth applications, voice and music technologies and tuning tools for

　　reference headset and speaker applications and supports developers with greater differentiation capabilities in a single-chip design.

　　Qualcomm aptX, Qualcomm Kalimba and CSR8675 are products of Qualcomm Technologies, Inc. and/or its subsidiaries.

　　Premium tier Bluetooth® audio flash platform

　　with support for Qualcomm® aptX™ HD

　　Audio and active noise cancellation*

　　Qualcomm®

　　CSR8675

　　Bluetooth Audio Platform

　　This material is subject to change without notice.

　　87-CE852-1 Rev B

　　* Available via separate software download.

　　Features CSR8675 Block Diagram

　　Bluetooth Audio Flash Applications

　　• Speakerphones

　　• Stereo Speakers

　　• Stereo Headphones

　　• Stereo Headsets

　　• Wireless Earbuds

　　• Soundbars

　　Qualcomm cVc, Qualcomm meloD, GAIA and Qualcomm TrueWireless Stereo are products of Qualcomm Technologies, Inc.

　　and/or its subsidiaries. eXtension is a program of Qualcomm Technologies, Inc. and/or its subsidiaries.

　　©2018 Qualcomm Technologies International, Ltd. All Rights Reserved. Qualcomm is a trademark of Qualcomm Incorporated,

　　registered in the United States and other countries. Qualcomm TrueWireless is a trademark of Qualcomm Incorporated. aptX, cVc,

　　meloD and Kalimba are trademarks of Qualcomm Technologies International, Ltd., registered in the United States and other

　　countries. The Bluetooth® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any use of such marks

　　by Qualcomm Technologies International, Ltd. is under license. Other products and brand names may be trademarks or registered

　　trademarks of their respective owners. 0518A

　　To learn more visit: qualcomm.com

　　z Bluetooth version 4.2 compliant

　　z 120 MHz programmable Kalimba DSP with integrated multipoint A2DP and HFP audio applications

　　z aptX, aptX Low Latency, aptX HD, MP3,AAC and SBC audio codecs

　　z 2-mic Qualcomm® cVc™ 8th Generation Noise Cancellation Technology with wideband speech

　　z Audio tuning suite with audio enhancements and two 5-band EQs

　　z GAIA V2 and associated Android & iOS example apps for enhanced connectivity with mobile devices

　　z Link Layer Topology support for  enhanced multi-device co-existence

　　z Qualcomm TrueWireless™ Stereo

　　z Two I2S ports for enhanced audio connectivity capabilities with external components

　　z Support for Apple MFi1 & Apple ANCS for enhanced communication with iOS devices

　　z Qualcomm® meloD™ Audio Processing stereo widening technology

　　z Compatible with third party solutions available from selected eXtension Program members