When a monocomponent signal with slowly changing instantaneous frequency is burred by noise

its instantaneous frequency is usually added by many high crest and low trough.But real instantaneous frequency is a trend in estimated instantaneous frequency if signal to noise ratio is not very high.Though Maximum likelihood method can smooth some higher crest and lower trough

real instantaneous frequency is still not very obvious.A new non-parameter instantaneous frequency estimation method is established based on a new method:Local-wave method.Firstly

smoothed versions of the Phase Difference Estimator——Maximum likelihood method is adopted to estimate the instantaneous frequency.Then more accurate instantaneous frequency can be shifted as a trend by the local-wave method.A simulation is used to test this new method.The result shows the method described in the paper is proved to be more accurate and less computation.