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专利名称：Automatic equalizing system with DFT and
FFT
发明人：Franciscus J. Op De Beek,Jacob M. Van
Nieuwland
申请号：US06/579737申请日：19840213公开号：US04628530A公开日：19861209
摘要：The equalizing arrangement in accordance with the invention comprises anequalizing unit (4) for correcting the frequency characteristic of an electric signal appliedto its first input (7) under the influence of a control signal (10) applied to its second input(8) and for supplying a corrected electric signal to its output (9), and a frequencyanalyzing unit (16) having a first input (15) coupled to a point in the signal path betweenthe input terminal (1) and the first input (7) of the equalizing unit (4), a second input (17)coupled to the pick-up means (14) and an output (19) for supplying the control signal(10).
The analyzing unit (16) is constructed to apply a Fourier transform to the previouslydigitized input signals x(t) and y(t) applied to its first and its second input, to computeFourier-transformed signals F.sub.x (f) and F.sub.y (f) of these two signals and to computea transfer function between these two signals.
Preferably the frequency analyzing unit is further constructed to compute a
coherence function . gamma..sup.2.sub.xy (f) between the two signals and, in determiningthe control signal, to ignore the values of the transfer function for those frequencies
f.sub.i for which &ggr;.sup.2.sub.xy is smaller than a specific value, for example 0.8. Bymeans of the arrangement in accordance with the invention a better equalization can beachived and the distortion of the output signal of the arrangement is low.
申请人：U. S. PHILIPS CORPORATION
代理人：Thomas A. Briody,William J. Streeter,Marianne R. Rich
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