Chao at 06:32, 13 July 2018

2018-07-13T06:32:22Z

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== IC solutions ==
{| class="wikitable sortable"
|-
! Header text !! Some models !! Bluetooth !! A2DP, AVRCP, HFP, etc !! Output Analog / I2S / SPDIF !! TWS !! APTx !! Features
|-
| OVC3860 || OmniVision || V2.0+EDR || A2DP V1.2, AVRCP V1.4 || ? || || ||
|-
| CSR8635 || qualcomm CSR || V4.1 || A2DP v1.2, AVRCP v1.4, HFP v1.6, HSP v1.2, DI v1.3 || Analog || X || || Stero
|-
| CSR8645 || qualcomm CSR || || A2DP，AVRCP，HFP，AAC || X || X || APTx || Stero,
|-
| CSR8670 || qualcomm CSR || '''V5.0''' || A2DP V1.31, AVRCP V1.6, HFP 1.7 HSP 1.2, etc || Analog / I2S / SPDIF || TWS || APTx, APTx-LL, APTx-HD ||
|-
| CSR8675 || qualcomm CSR || '''V5.0''' || A2DP v1.3.1, AVRCP v1.6, HFP v1.7, HSP v1.2, MAP v1.1, PBAP v1.1.1, DID v1.1 || Analog / I2S / SPDIF || TWS || APTx ||
|-
| BlueCore5 || qualcomm CSR || V2.1+EDR || A2DP V1.2, AVRCPV1.4 || || || ||
|-
| [[CSRA64215]] || qualcomm CSR || V4.2 || A2DP V1.3, AVRCP V1.6, HFP v1.6, HSP v1.2, DI v1.3 || I2S || TWS || APTx, APTx-LL ||
|-
| CSRA63225 || qualcomm CSR || || || || || ||
|-
| BK8000L || Beken || V2.1 + EDR, +SPP || A2DP v1.2, AVRCP v1.0 || || || || Aux-in, key control
|-
| BK8002 || Beken || V2.1 + EDR, +SPP || || || || || Aux-in, TF/SD, sequential MP3, FM(not good), key control
|-
| BK8008 || Beken || || || || TWS || ||
|-
| BK3254 || Beken || V4.1 || || || || ||
|-
| BK3260 || Beken || V4.2 || || || || ||
|-
| BK3266 || Beken || V4.2 || || || || || Aux-in, TF/SD, USB Disk, sequential MP3, change name, key control
|-
| 66xx || Buildwin (appotech Jianrong) || || || || || ||
|-
| RDA5856 || RDA || || || || || ||
|-
| - || [[JL]] || || || || || ||
|-
| IS1861S || ISS || || || || || ||
|-
| BM2020 || Sunrise || || || || || ||
|}

== Concept ==
{| class="wikitable sortable"
|-
! Header text !! English !! Header text
|-
| A2DP || Advanced Audio Distribution Profile|| Example
|-
| AVRCP || Audio/Video Remote Control Profile|| Example
|-
| HFP || hand-free profile || 免提通话功能
|-
| TWS || Qualcomm TrueWireless™ Stereo (TWS), which allows two devices to be configured as a stereo pair || 无线对笔功能，即一个手机可以同时连接2台蓝牙音箱，区分左右声道
|-
| AAC || codec ||
|-
| I2S || 数字音频输出
|-
| APTx, APTX-LL, APTX-HD || codec, qualcomm only https://en.wikipedia.org/wiki/AptX || 提升音质，减小延时，需要设备端（电脑、手机、平板〕也支持
|-
| ||
|-
| EDR || Enhanced Data Rate ||
|}

=== Current noise ===
Power
* Use soldering instead wires on power, or as short as possible, wires has large resistance.
* Better use linear regulator, if use DC-DC must avoid ripples, add LC circuits filter. See left side.(L - 10UH, D - 4148, C - 10~100UF)
[[File:Bt-audio 01.png|thumbnail]]
* For normal AC-DC adapter, inductor can skipped.
* voltage must be 5V, not over 5V, 5.1-5.4V is not good
* Must lead out two wires to connect to power ground and audio ground seperatedly.
Other issues
* avoid interference signal, avoid large-size metals, avoid router, high power unit, etc
* avoid fully closed metal case
* Check different ground connection point to see the best place
* do not touch it
* If still noise, try to power supply amplifier and bluetooth module board seperately
=== Weak bluetooth signal ===
* Powr supply interference, ripples
* Power supply incorrect voltage
* delete former matched modules, and re-pair

[[category: Bluetooth]]

Category:BT Audio - Revision history

Chao at 06:32, 13 July 2018