MODULATION ACCURACY MEASURING METHOD AND MEASURING INSTRUMENT

摘要

PROBLEM TO BE SOLVED: To improve measurement accuracy by correcting the effect of noise occurring in a measuring instrument in a modulation accuracy measuring instrument. SOLUTION: The correction quantity of I/Q coordinate vectors due to a modulation accuracy measurement result deterioration factor (noise of a preprocessing part 10a, etc.), is preliminarily measured by using a reference signal. A data inputting means 10 converts an analog input signal to be measured into digital data. An orthogonal demodulating means 11 performs orthogonal demodulation processing to convert it into a baseband signal. A correcting means 14 regards symbol identification point data of an I/Q extracted by a symbol identification point extracting means 12 as vectors of the I/Q coordinates and adds the vector with size of correction quantity in the direction of an ideal symbol position. A modulation accuracy operating means 15 performs modulation accuracy operation based on corrected symbol identification point. It is possible to reduce the deterioration of measured results due to noise, etc., that takes place in the measuring instrument by adding a correction vector to a measurement symbol identification point.