Patent ID: 6249398
Filing Date: 2001-06-19
Classification: G11B

Abstract:
A magnetic recording and playback system including a moving magnetic data storage medium defining a data storage surface, a data transducer head positionable by head positioning means relative to a track formed on the data storage surface for storing user data in the form of magnetic flux transitions, the system further including a partial response, maximum likelihood data channel comprising:an analog signal path coupled to the data transducer head and forming a read signal responsive to flux transitions during a read operation of the disk drive;quantization means for quantizing samples of the read signal to form a series of samples;an FIR filter for filtering the series of samples so as to implement a non-canonical fixed partial response target which has a spectral null at DC and a spectral depression at the Nyquist sampling frequency; anda Viterbi detector having at least sixteen states and being arranged for maximum likelihood decoding of the filtered series of samples so as to form a series of detected bits.