| 摘要 |
PURPOSE:To remove a negative peak and to obtain a playback signal of good quality by performing equalization corresponding to a position shift in negative peak generated owing to variation in relative speed between a magnetic head and a discoid recording medium at a radial position. CONSTITUTION:A tap selecting circuit 8 changes circuit element taps of the 1st delay circuit 7 corresponding to a position signal. For example, when a magnetic head is at an inner peripheral position, such a tap that the quantity is DELTAT less than when it is at an outer peripheral position is selected and a signal which is DELTAT different as shown in figure E is generated. Signals E and G inputted to the 2nd input terminals are added together by an adder 3, which outputs a signal H from which the negative peak is removed. Thus, a tap is selected and the quantity of delay is set in inverse proportion to the relative speed between the head and medium to perform optimum waveform equalization over all tracks. Output signals F and G are summed up by the adder 3 to narrow down the half-value width of the positive peak of a recording signal, thereby improving the quality of the playback signal. |
