| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a digital modulation signal generating apparatus capable of generating a digital modulation signal with high modulation accuracy over a broad modulation band. <P>SOLUTION: The digital modulation signal generating apparatus includes: an error compensation section 22 for compensating an offset error and a quadrature error of a quadrature modulator 14 and located between a baseband signal generating section 11 and a D/A converter 12; and a frequency characteristic compensation section 23 for compensating an amplitude versus frequency characteristic and a phase versus frequency characteristic in the modulation frequency band for a signal path from the baseband signal generating section 11 to the quadrature modulator 14. Further, a baseband signal obtained by demodulating an output signal from the quadrature modulator 14 by a demodulation section 31 is given to an error detection section 32 and an adaptive equalizer 33. The error detection section 32 obtains information required for compensating the offset error and the quadrature error and sets it to the error compensation section 22, and the adaptive equalizer 33 obtains a filter factor of a filter for converting the received baseband signal into a signal providing a minimum error with respect to an ideal signal and sets it to the frequency characteristic compensation section 23. <P>COPYRIGHT: (C)2007,JPO&INPIT |
