| 摘要 |
PURPOSE:To attain quick and accurate search, by producing a kick pulse to shift a pickup by a distance, when the distance between the present position of the pickup and the objective position exists within a prescribed range for a DAD device. CONSTITUTION:An absolute address of the present position is read out from a memory 153 and an absolute address of the objective position is outputted from an adder 157 and position calculating circuits 158, 159 calculate distance information. The absolute value of the difference is outputted from a subtraction circuit 160 to be a distance data between the present position and the objective position of the pickup 142. This data is set to a shift amount calculating counter 161 as an initial data and applied to a kick pulse generating circuit 162. A subtraction circuit 163 inputs the said absolute address and outputs the time difference between the present position and the objective position of the pickup. The subtraction circuit 163 supplies the polarity signal in response to the result of subtraction to the circuits 166 and 167. The circuit 162 produces a kick pulse shifting the pickup by a distance corresponding to the distance data from the subtraction circuit 160. |
