| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide multiple analog and digital downconversion. <P>SOLUTION: In a carrier recovery method using multiple stages of carrier frequency recovery, a receiver uses multiple frequency generation sources to generate carrier signals used to downconvert a received signal. An analog frequency reference 114 having a wide frequency range and coarse frequency resolution is used in conjunction with a digital frequency reference 110 having a narrow frequency range and fine frequency resolution. The multiple carrier signals are multiplied by a received signal to effect a multi-stage downconversion, resulting in a baseband signal. A frequency tracking module 108 measures the residual frequency error present in the baseband signal. The measured residual frequency error is then used to adjust the frequencies of the carrier signals generated by the multiple frequency generation sources 114 and 110 through a processor. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
