IT技(ji)術互動交流平台(tai)

大发11选5官网

來源︰IT165收集  發布日期︰2020-02-27 15:45:50

大发11选5官网

WBS(wide band speech)通(tong)俗來講就是(shi)藍牙寬帶通(tong)話,通(tong)話數據frequency 16K,采用msbc編解(jie)碼(chip中實現)
和(he)NBS(narrow band speech)相對,NBS通(tong)俗來講是(shi)窄帶通(tong)話,通(tong)話數據frequency 8K,采用CSVD編解(jie)碼(chip中實現)
NBS是(shi)默認

大发11选5官网

要實現WBS,總體來說比較xi)叢br />要分兩個階段進行(xing)︰
1.profile層(HFP AT COMMAND)
2.control bluetooth chip(如(ru) CSR 通(tong)過 BCCMD)

大发11选5官网

步驟(zhou)︰
1.First, in the initialization procedure, the HF shall send the AT+BRSF=<HF supported features>
command to the AG to both notify the AG of the supported features in the HF, as well as to
retrieve the supported features in the AG using the +BRSF result code.
2.Secondly, in the initialization procedure, if the HF supports the Codec Negotiation feature, it
shall check if the AT+BRSF command response from the AG has indicated that it supports the
Codec Negotiation feature. If both the HF and AG do support the Codec Negotiation feature
then the HF shall send the AT+BAC=<HF available codecs> command to the AG to notify the
AG of the available codecs in the HF.


HF Feature:

AG Feature:

3.通(tong)話時,AG會發送過來+BCS=ID
我(wo)們回復AT+BCS=ID

大发11选5官网


實例︰

這樣(yang)接受了SCO連接,相當于profile層面(mian)啟動了WBS

通(tong)過空中包分析(xi)發現編碼方式確實變成了msbc

通(tong)常這時候要把MIC,PCM_IN,PCM_OUT,SPEAKER切換成16K

但是(shi)現在問題來了,切換16K後為(wei)什麼還全都是(shi)雜音呢?
揭曉答案(an)︰
HFP profile層面(mian)只(zhi)是(shi)通(tong)知手zhi)﹦xing)WBS通(tong)話了,但是(shi)local chip並不(bu)知道,也不(bu)會解(jie)析(xi)HFP層面(mian)的(de)AT command
所(suo)以我(wo)們應該有(you)一些(xie)機制告知chip一些(xie)消(xiao)息,如(ru)CSR 需要 BCCMD告知,每(mei)個chip廠商都有(you)自己的(de)策略

由(you)于告知芯(xin)片這個過程比較xi)叢櫻 suo)以在下(xia)篇文章介(jie)紹(拿CSR舉(ju)例)

大发11选5官网

    Tag標簽︰藍牙  寬帶  
    • 大发11选5官网

    About IT165 - 廣告服務 - 隱私聲(sheng)明 - 版權申明 - 免責(ze)條款 - 網站地圖 - 網友投稿 - 聯系方式
    本站內容來自于互聯網,僅(jin)供用于網絡技(ji)術學習(xi),學習(xi)中請遵循相關法律法規
    大发11选5官网 | 下一页