Patent attributes
A digital frequency converter is provided that maintains a high power efficiency in an EER scheme despite the inclusion of digital signal processing. An inputted modulated signal is converted into phase information and amplitude information of a polar coordinate type. The amplitude information is outputted as amplitude information of the digital frequency converter. Meanwhile, phase change of a frequency f2, which is outputted from an accumulator, corresponding to lower ‘Q’ figures of phase data PD for frequency conversion is added to the phase information by an adder. In addition, a sampling frequency of the phase information outputted from the adder is upsampled by an interpolator, and also, phase change of a frequency f3, is converted into a phase-modulated signal of an orthogonal coordinate type, and then outputted as phase information of the digital frequency converter.
