Multi - level quadrature amplitude modulation 多電平正交調幅
Qam for quadrature amplitude modulation 積分幅度調制
Quadrature amplitude modulation qam 正交幅度調制
Qam for quadrature amplitude modulation 四相調制
Quadrature amplitude modulation 正交振幅調幅法
Quadrature amplitude modulation 正交幅度調制
As a high band - efficiency digital modulation scheme , dvbc ( digital video broadcasting of cable ) qam ( quadrature amplitude modulation ) modulator is widely adopted in the wide - band communication area , such as hdtv broadcasting , cable modem , microwave communication , satellite communication and so on 正交幅度調制器( qammodulator )作為一種高頻譜利用率的數字調制方式,在高清晰度電視( hdtv )廣播、 cablemodem 、固定寬帶無線接入、衛星通信、數字微波傳輸等寬帶通信領域得到了廣泛應用。
By adopting qam ( quadrature amplitude modulation ) modulation , we have researched and implemented a high - speed data broadcasting system compatible with dvb ( digital video broadcasting ) standard in the past years , and integrated and applicated the system into sdh / hfc ( synchronous digital hierarchy / hybrid fiber coax ) network for the first time in china 經過多年的研究,開發出了符合dvb標準、采用qam調制方式的陽光網高速數據廣播系統,同時在國內首次實現了基于sdh hfc網絡的高速數據廣播系統集成應用。
This thesis begins with hfc network theory and docsis , analyses modulation / demodulation process of data communication in hfc . then , several theories are analysed including qam ( quadrature amplitude modulation ) , nyquist root square filter , fec ( forward error correction ) , map ( bandwidth allocation map ) . and digital signal transmission involved the other important international standard ? itu - t j . 83 annex a / b , is discussed 本文從hfc網絡理論和docsis協議入手,分析了hfc數據通信的調制解調過程,對qam調制、奈奎斯特均方根濾波器、前向糾錯( forwarderrorcorrection ,簡稱fec ) 、 map通信等進行了闡述;還從中探討了電纜調制解調器需要用到的另一個國際標準ituj . 83annexa / b所設計的mpeg信號的數字傳輸。
百科解釋
Quadrature amplitude modulation (QAM) is both an analog and a digital modulation scheme. It conveys two analog message signals, or two digital bit streams, by changing (modulating) the amplitudes of two carrier waves, using the amplitude-shift keying (ASK) digital modulation scheme or amplitude modulation (AM) analog modulation scheme.