Quadrature multiplexed binary offset carrier(QMBOC)signal is a relatively complicated novel modulated signal adopted by the BeiDou system.Digital and analog distortion characteristics including time delay

attenuation factor of the QMBOC signal are analyzed based on the binary offset carrier(BOC)distortion model.The internal relationship of distortion between component signals and the combined signal.The effects of different distortion parameters on correlated power of the signal are analyzed.The simulation analysis demonstrates a clear distinction in the digital and analog distortion of the signal before and after the combination of circuit.functional relationship of mean waveform distortion and correlation coefficient between the branch and the combined circuit.In the correlated power experiments

when the level of digital and analog distortion in the Q branch exceeds that in the I branch

the correlated powers are significantly decreased.This study reveals the influence relationship of distortion parameters between the QMBOC combined signal and the component signal.This finding offers valuable theoretical support for anomaly analysis of the BeiDou QMBOC signal

effectively supports signal quality monitoring(SQM)work of QMBOC.