| 摘要 |
PROBLEM TO BE SOLVED: To provide the orthogonal signal generator that generates two high frequency signals which has a phase difference by 90 degrees accurately through automatic adjustment. SOLUTION: A 1st frequency signal outputted from an oscillator 10 is distributed into two; the one is outputted as it is to a 1st output terminal 12a and the other is given to a 90 deg. phase shifter 14, where a phase difference of 90 deg. is provided to the other signal and the resulting signal is outputted to a 2nd output terminal 12b, resulting in generating two 1st frequency signals. A low frequency orthogonal signal generating means 30 outputs two 2nd frequency signals whose frequency (2nd frequency) is lower than the 1st frequency and which has a phase difference of 90 deg.. The 1st and 2nd frequency signals in pairs are mixed by 1st and 2nd balanced modulation means 32, 36 respectively and the outputs of them are given to an adder subtractor means 34, where they are summed, the sum is detected by a square detection means 38, and a filter means 40 extracts a signal having a frequency component twice the 2nd frequency from the detection output of the means 38. A control means 46 controls the 90 deg. phase shifter 14 so that the amplitude of the extracted signal is minimized. |
