公开(公告)号：EP0940957B1

公开(公告)日：2008-01-02

申请号：EP98943037.6

申请日：1998-09-18

申请人： NIPPON HOSO KYOKAI

发明人： SHIBUYA, Kazuhiko ,  KUMADA, Junji ,  IWADATE, Yuichi ,  HAMAZUMI, Hiroyuki ,  NOMOTO, Toshihiro ,  TAKANO, Kouichi ,  SAITO, Tomohiro ,  TANAKA, Shoji ,  MINEMATSU, Fumiaki ,  HASHIMOTO, Akinori ,  ITOH, Shigeyuki ,  MATSUMURA, Hajime ,  KATOH, Hisakazu ,  TAKECHI, Masaru

IPC分类号： H04L27/22 ,  H04N5/455 ,  H04L27/227

CPC分类号： H03J7/02 ,  H04L27/22 ,  H04L2027/0057 ,  H04N5/4401 ,  H04N5/455 ,  H04N5/50

摘要： A carrier reproducing circuit which can stably reproduce carriers even when the CN ratio is low by measuring the phase of a signal by only using such a period that the multi-valued number is few and controlling a VCO or NCO (numerically controlled oscillator). At the time of reproducing the carriers, the occurrence of a pseudo-synchronous phenomenon is avoided in such a way that rough AFC is performed by inserting SYNC which is modulated with an already known pattern and has a relatively short length into modulated waves and the oscillation frequency of the VCO or NCO is swept over a wide range, and then, the sweeping is stopped at a frequency at which the SYNC is received. In addition, the period of a few multi-valued number having a certain degree of length is provided in the modulated waves and the difference between the frequency of received modulated signals and that of the local oscillation signal of the VCO or NCO in the period is determined, and then, the frequency difference is analyzed by using the phase differential function method, autocorrelation function method, or count method, etc., and the VCO or NCO is controlled based on the results of the analysis.

公开(公告)号：EP0940957A1

公开(公告)日：1999-09-08

申请号：EP98943037.6

申请日：1998-09-18

申请人： NIPPON HOSO KYOKAI

发明人： SHIBUYA, Kazuhiko ,  KUMADA, Junji ,  IWADATE, Yuichi ,  HAMAZUMI, Hiroyuki ,  NOMOTO, Toshihiro ,  TAKANO, Kouichi ,  SAITO, Tomohiro ,  TANAKA, Shoji ,  MINEMATSU, Fumiaki ,  HASHIMOTO, Akinori ,  ITOH, Shigeyuki ,  MATSUMURA, Hajime ,  KATOH, Hisakazu ,  TAKECHI, Masaru

IPC分类号： H04L27/22 ,  H04N5/455

CPC分类号： H03J7/02 ,  H04L27/22 ,  H04L2027/0057 ,  H04N5/4401 ,  H04N5/455 ,  H04N5/50

摘要： Stabilized carrier recovery is acheived even at the time of a low C/N ratio by measuring the phase of a signal and controlling VCO or NCO (Numerical Controlled Oscillator) using only a period having few constellation points. At this time, false lock phenomenon is avoided as follows. That is, relatively short SYNC modulated by an already-known pattern is entered into a modulation wave, VCO or NCO oscillation frequency is swept in a wide range and sweep is stopped at a frequency in which the SYNC can be received, thereby carrying out coarse control AFC. Further, a period having long to some extent, having few constellation points is provided in the modulation wave and then, a difference between the frequency of a received modulated signal and a local oscillation signal of VCO or NCO is obtained in this period. This frequency difference is analyzed according to the phase differential function method, self-correlation function method or count method, and the VCO or NCO is controlled based on this result of analysis.

摘要翻译： 即使在C / N比较低的时候，通过测量信号的相位并且仅使用具有很少星座点的周期来控制VCO或NCO（数控振荡器），稳定的载波恢复也是可以实现的。 此时，如下所示避免假锁现象。 也就是说，通过已知的模式调制的相对较短的SYNC被输入到调制波中，VCO或NCO振荡频率在宽范围内被扫描，并且在可以接收SYNC的频率上停止扫描，从而执行粗略 控制AFC。 此外，在调制波中提供了具有很少的星座点的长时间段，然后在该周期中获得接收到的调制信号的频率与VCO或NCO的本地振荡信号之间的差。 根据相位差函数法，自相关函数法或计数法对该频差进行分析，并根据该分析结果对VCO或NCO进行控制。