| 摘要 |
PURPOSE:To absorb the change of voltage due to the position of the magnetic head by changing over the gain based on the information of position of the magnetic head before the AGC circuit. CONSTITUTION:The interest change over circuit 7 for carrying out the gain change over based on the positional information of the magnetic head 2 before AGC circuit 4 is provided. Namely, when the head 2 is disposed at the outer circumference of the magnetic disc 1, the gain is changed over to be lowered completely, and when it is suitated at the inner circumference of the magnetic disc, the gain is changed over to be restrain the lowering thereof. In this manner, the change of voltage due to the position of the head 2 in the change of the voltage can be substantially absorbed by the change over circuit 7. Accordingly, the remaining voltage change is included within dynamic range of the AGC circuit and the change can be absorbed completely. |
