The modified method of stationary harmonic noise filtration on basis of discrete Fourier transformation is offered.
This method is especially effective if the noise is concentrated in useful signal frequencies,
when using well-known rejection filters can deform the useful signal in consequence of spectrum leakage effect.
The mathemamatical justification of the offered improvements of this meyhod, 
maximally saving the form of useful signal is given.
The result of experiments confirmed that such procedure allows to effective suppress 
of the concentrated frequency noise without substantial distorions of informative 
fragments of useful signsl even in those cases, when frequency of noise is concentrated 
in the interval of the loaded frequencies of useful signal.