Abstract-The effect of the companding process on QAM signals
has been under investigation for the past several years. The
compander, included in the PCM telephone network to improve
voice performance, has an unusual affect on digital QAM data
signals which are transmitted over the same channel. The quantization
noise, generated by the companding process which is multiplicative
(and asymmetric), degrades the detectability performance
of the outermost points of the QAM constellation more
than that of the inner points.
The combined effect of the companding noise and the inherent
white gaussian noise of the system, leads us to a re-examination of
signal constellation design.
In this paper we investigate the detectability performance of a
number of candidates for signal constellations including, a typical
rectangular QAM constellation, the same constellation with the
addition of a smear-desmear operation, and two new improved
QAM constellation designs with two-dimensional warpi
標(biāo)簽：
investigation
Abstract-The
companding
the
上傳時(shí)間：
2013-12-20
上傳用戶：英雄
變易工作室制作
AMC錄音控件TACMWaveIn和TACMWaveOut
更新日期:2004-12-11
VER 2.0 增加了錄音過(guò)濾雜音功能
QQ:41426277 EM:41426277@163.COM
此控件沒(méi)有注冊(cè),只能用20分鐘
使用PCM采集數(shù)據(jù)G711壓縮格式,只支持流式傳送,
不支持保存文件
////////////////////////////
2.0說(shuō)明
1.0支持系統(tǒng)的錄音多種格式,有一定的延時(shí),沒(méi)有過(guò)濾雜音功能.
2.0已取消支持系統(tǒng)的錄音多種格式,使用PCM采集數(shù)據(jù)G711A壓縮格式
(8000HZ單聲道16位格式錄音每秒以8K完成數(shù)據(jù),16000HZ單聲道
16位格式錄音每秒以11K完成數(shù)據(jù),音質(zhì)相當(dāng)好),延時(shí)降低到最小
100-500MS以內(nèi),不會(huì)隨時(shí)間增加而增加延時(shí)(如果是說(shuō)話測(cè)試一直保持
200MS的延時(shí),如果是用播放歌曲來(lái)測(cè)試,有自動(dòng)校正延時(shí)功能,恢
復(fù)成200MS的延時(shí),恢復(fù)過(guò)程中不會(huì)中斷歌曲的播放,只是小小加快唱
歌的速度,聽(tīng)覺(jué)不會(huì)覺(jué)察出來(lái)),加入了過(guò)濾雜音功能.
/////////////////////////
////////////////////////////
2.0安裝
將ACMG711.dll復(fù)制到系統(tǒng)文件夾里
再安裝控件
/////////////////////////
產(chǎn)品號(hào):BYACMWave20 ,請(qǐng)查詢注冊(cè)號(hào)
標(biāo)簽：
TACMWaveOut
TACMWaveIn
41426277
4142627
上傳時(shí)間：
2013-12-31
上傳用戶：eclipse
