Radar m.t.i.: a comparison of 2nd-order digital-filter realisations when the stopband is very narrow

Design of recursive digital m.t.i. filters becomes difficult when the cutoff frequency is as low as 1/100 p.r.f., because the filter may have large internal gain, generate high noise levels and have a response which is sensitive to parameter errors. The results of a study of 2nd-order sections are described and two realisations which minimise the word length are presented.