| 摘要 |
PROBLEM TO BE SOLVED: To prevent gain difference, phase difference and a DC offset from occurring between in-phase component data and orthogonal component data by providing one D/A converter and executing a digital signal processing in sampling frequency conversion and an orthogonal modulation. SOLUTION: Input data is converted into a sampling frequency by an interpolator 4, sent to a filter 6 and, moreover, transmitted to a multiplier 8. In the same way, orthogonal component data of the sampling frequency is inputted to the interpolator 5 with an input terminal 2 and orthogonal component data which is converted into the sampling frequency is transmitted to the multiplier 9 through the interpolator 5 and a filter 7. In-phase component data converted into the sampling frequency is multiplied by cos(2.π.fcT) by the multiplier 8 and orthogonal data is multiplied by sin(2.π.fc.T) by the multiplier 9. Then, they are added by an adder 10, transmitted to the D/A converter 11, converted into analog data and outputted as orthogonally converted data through an output terminal 3.
|
