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
標簽:
investigation
Abstract-The
companding
the
上傳時間:
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 增加了錄音過濾雜音功能
QQ:41426277 EM:41426277@163.COM
此控件沒有注冊,只能用20分鐘
使用PCM采集數據G711壓縮格式,只支持流式傳送,
不支持保存文件
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2.0說明
1.0支持系統的錄音多種格式,有一定的延時,沒有過濾雜音功能.
2.0已取消支持系統的錄音多種格式,使用PCM采集數據G711A壓縮格式
(8000HZ單聲道16位格式錄音每秒以8K完成數據,16000HZ單聲道
16位格式錄音每秒以11K完成數據,音質相當好),延時降低到最小
100-500MS以內,不會隨時間增加而增加延時(如果是說話測試一直保持
200MS的延時,如果是用播放歌曲來測試,有自動校正延時功能,恢
復成200MS的延時,恢復過程中不會中斷歌曲的播放,只是小小加快唱
歌的速度,聽覺不會覺察出來),加入了過濾雜音功能.
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2.0安裝
將ACMG711.dll復制到系統文件夾里
再安裝控件
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產品號:BYACMWave20 ,請查詢注冊號
標簽:
TACMWaveOut
TACMWaveIn
41426277
4142627
上傳時間:
2013-12-31
上傳用戶:eclipse