Automatic equalizer

DETAILED DESCRIPTION Accordingly, it is an object of the present invention to provide an improved automatic equalizer that can eliminate the above-noted defects inherent in previously proposed systems.
Another object of this invention is to provide an automatic equalizer in which the characteristic parameters can be efficiently and reliably converged into optimum values to afford optimum equalizer characteristics to the input signal.
It is a further object of the present invention to provide a signal reproducing apparatus adapted to reproduce signals without use of a tracking servo, wherein automatic setting of the equalizing characteristics can be realized by a simplified arrangement over previously proposed systems.
It is a still further object of the present invention to provide a signal reproducing apparatus having an automatic equalizing function for efficiently extracting changes caused in the characteristic parameters of the equalizer between odd-number track tracings and even-number track tracings.
According to an aspect of the present invention an automatic equalizer is provided in which the equalizer parameters are variable in response to the extent of change in the error rate of the output signal being equalized.
The output signal error rates are sequentially detected at a number of measurement points that correspond to preset characteristic parameters in order to determine a minimum error rate measurement point.
The characteristic parameters are finally determined by a process in which the parameters of the equalizer are varied in an orthogonal relationship that is independent of any head sequence involved in the reproduction of the signal being equalized.
The orthogonal variation process involves making minute changes within a predetermined range and varying the characteristic parameters of the equalizer in a direction to diminish the signal error rate of the output signal on the basis of the detected degree of change of the signal error rate.
The above and other objects, features, and advantages of the present invention will become apparent upon reading the following description in conjunction with the accompanying drawings, in which the novel matter is pointed out in the claims