Frequency mixer group delay measuring circuit and method

The invention provides a frequency mixer group delay measuring circuit which comprises a vector network analyzer and a comb generator. The vector network analyzer comprises a first frequency synthesizer, a second frequency synthesizer and a receiver. The output signals of the first frequency synthesizer are divided into two channels through a first coupler, one channel signals are coupled to the radio-frequency signal input end of a frequency mixer to be tested, and the other channel signals are coupled to the receiver. The output signals of the second frequency mixer are coupled to the local oscillating signal input end of the frequency mixer to be tested. The vector network analyzer further comprises a reference oscillator, the output end of the reference oscillator is coupled to the input end of the comb generator, the output end of the comb generator and the output end of the frequency mixer to be tested are coupled to the input end of a second coupler together, and the output end of the second coupler are coupled to the receiver. The frequency mixer group delay measuring circuit can achieve the measurement of the phase position of a measurement channel conveniently and fast, and achieve phase error correction accurately.