Patent ID: 8305858
Filing Date: 2012-11-06
Classification: G11B

Abstract:
1. A variable delay circuit, comprising: a delay line in which a delay amount is variably set; a delay setting unit that performs a delay setting of the delay line using a unit delay control value for executing delay of the delay amount to be given for an input signal to the delay line and delay of a predetermined unit delay amount in the delay line; a pulse generator that, in a calibration period, overlaps a test pulse with the input signal, and generates a comparison pulse having the unit delay amount with respect to the test pulse; and a unit delay determining unit that sets the delay of the unit delay amount in the delay line by providing the unit delay control value to the delay setting unit in the calibration period, determines the unit delay control value equivalent to the unit delay amount based on a phase comparison result between the comparison pulse and the test pulse in which the unit delay amount is applied through the delay line, and provides, to the delay setting unit, the determined unit delay control value as the unit delay control value of a calibration result.