发明名称 |
AFC circuit, carrier recovery circuit and receiver device capable of regenerating a carrier reliably even at the time of low C/N ratio |
摘要 |
Stabilized carrier recovery is achieved 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.
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申请公布号 |
US6490010(B1) |
申请公布日期 |
2002.12.03 |
申请号 |
US19990308263 |
申请日期 |
1999.05.14 |
申请人 |
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 |
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 |
分类号 |
H03J7/02;H03L7/06;H04B1/10;H04L27/00;H04L27/22;H04L27/227;H04N5/44;H04N5/455;H04N5/50;H04N7/20;(IPC1-7):H04N5/50 |
主分类号 |
H03J7/02 |
代理机构 |
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主权项 |
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