Cross-correlation phase noise detecting device

The invention discloses a cross-correlation phase noise detecting device which comprises a to-be-detected signal phase detecting unit, a reference signal phase detecting unit, a first subtracter, a second subtracter and a crosspower spectrum computation module. The technical scheme adopted by the cross-correlation phase noise detecting device provided by the invention has the following advantages: an input signal frequency can cover any single-frequency point within a range of hundreds of megabytes, and real-time measurement to near carrier frequency phase noise is achieved; a testing system does not require a reference source which is the same as a to-be-tested source in frequency and orthographic with the to-be-tested source; the characteristics of a digital filter are fixed, a phase rectification calibration and low-noise amplifier is not required, so that the testing uncertainty of the system is reduced; testing links such as scaling, locking and the like are eliminated, since operation is achieved through several keystrokes, real-time measurement results can be obtained, the operation is simple and easy, and the cost performance of the detecting device is high; compared with a digital phase noise measurement system for removing noise in the prior art, the cross-correlation testing system has the noise bottom indexes improved by about 30dBc/Hz.