| 摘要 |
PROBLEM TO BE SOLVED: To reduce phase noise.SOLUTION: The CW signal of an extension oscillator and the signal to be tested are synthesized, and the synthesized signal is supplied to an ADC 504. The digital data from the ADC 504 is converted into an IF signal by an IQ down-converter 512 that receives an LO signal from a first numerically controlled oscillator 510 tuned to the signal to be measured and processed by a first filter to become an IQ signal sample indicating the baseband of the signal to be measured, and also converted into an IF signal by an IQ down-converter 522 that receives an LO signal from a second numerically controlled oscillator 520 tuned to the CW signal and processed by a second filter to become a CW signal sample. A phase detection unit 540 measures the phase angle of the CW signal sample, and a phase correction unit 550 eliminates the phase noise of the IQ signal sample by using the measured phase angle. |
