| 摘要 |
A circuit and method for variably adjusting a data detecting level by using a pulse with modulation (PWM) signal. The pulse width modulation (PWM) signal having duty corresponding to a predetermined level control value is generated, and the level of the pulse width modulation (PWM) signal is detected to determine the data detecting level to a level corresponding to the detected level. A read test is performed while the level control value is incremented by a given stage from an initial level control value in response to a test mode, to determine the level control value less than that generating a data error by one stage to a maximum value. Further, the read test is implemented while the level control value is decremented by a given stage from the initial level control value, to determine the level control value greater than that generating the data error by one stage to a minimum value. Thus the initial level control value or level control value is obtained by an average value of the maximum and minimum level values. Therefore, the data detecting level adapted for each disk driving apparatus can be adjusted without modifying hardware of each disk driving apparatus, and the data error can be prevented by adaptively adjusting the data detecting level to operating circumstances.
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