| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a digital frequency converter that maintains a high power efficiency in an EER scheme despite the partial inclusion of digital signal processing in processing of the EER scheme. <P>SOLUTION: An inputted modulated signal is converted into phase information and amplitude information of a polar coordinate type by a phase detector 22 and an amplitude detector 23. The amplitude information is outputted as amplitude information of a digital frequency converter 2. Meanwhile, phase change of a frequency f2, which is outputted from an accumulator 27, corresponding to lower 'Q' figures of phase data PD for frequency conversion is added to the phase information using an adder 24. In addition, a sampling frequency of the phase information outputted from the adder 24 is upsampled by an interpolator 28, and also, phase change of a frequency f3, which is outputted from an accumulator 30, corresponding to higher (P-Q) figures of the phase data PD for frequency conversion is added to the upsampled phase information using an adder 29, further converted into a phase-modulated signal of an orthogonal coordinate type, and outputted as phase information of the digital frequency converter 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
