RECORDING TRACKING SERVO SIGNAL CIRCUIT

摘要

PURPOSE:To form a recording tracking servo signal prevented from interference with a clock signal by synthesizing a clock signal setting its duty ratio to a value other than 50% with a servo signal on the basis of programmed logical operation. CONSTITUTION:A servo signal (a) from a servo signal generator 1 is directly inputted to one input terminal of a direct and exclusive OR circuit 4. On the other hand, a clock signal (b) having higher frequency than that of the signal (a) and generated from a clock signal generator 2 is multiplied by two by a duty ratio changing circuit 3 and converted into a signal C having a duty ratio less than 50%. The signal C is inputted to the other input terminal of the circuit 4 and a signal (d) is outputted from the circuit 4. The signal (d) has both the information of the signals (a) and (b) and both the signals (a), (b) can be separated. The signal (d) is used as a recording tracking servo signal and prevented from interference with the clock signal (b).