| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a digital quadrature modulation circuit with high stability of frequency, wherein output carrier frequency is not influenced by the variation of sampling frequency of a digital baseband signal with low stability of frequency. <P>SOLUTION: A sampling clock of a sampling frequency generator 16 for processing a digital baseband signal is used for a quadrature carrier wave of digital quadrature modulation, and at the same time, is used as a signal for local signal generation for up-converting the quadrature modulation output. By this method, in a mixer 15 for the up-converting, frequency variation components of the sampling clock are canceled, and an output carrier signal with high stability of frequency is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
