Method and apparatus for separating magnetic and thermal components from an MR read signal

A signal separating apparatus for an information storage device including an information storage medium, comprising:

• a transducer including a magnetoresistive (MR) element;
• a read channel connected to the transducer to read a signal from the storage medium with the MR element in proximity with the storage medium;
• and
• a filter, coupled to the read channel, that filters the signal to extract a thermal signal component of the signal, the thermal signal component, representative of a thermal response of the MR element, provided at an output of the filter.

An information storage device, comprising:

• a transducer including a magnetoresistive (MR) element;
• a storage medium;
• means for moving at least one of the transducer and the medium to provide a relative movement between the transducer and the medium, the transducer being arranged relative to the medium such that a gap separates the MR element from the medium;
• a read channel connected to the transducer to read a signal from the medium using the MR element;
• and
• a filter, coupled to the read channel, that filters the signal to extract a thermal signal component of the signal, the thermal signal component, representative of a thermal response of the MR element, provided at an output of the filter.

A method of examining a medium using a signal induced in a magnetoresistive (MR) element spaced apart from the medium, comprising the steps of:

• reading the signal using the MR element as the MR element moves relative to the medium;
• detecting a variation in a thermal signal component of the signal read by the MR element;
• and
• determining a change in a characteristic of the medium from the variation in the thermal signal component.

An information storage device, comprising:

• a transducer including a magnetoresistive (MR) element;
• a storage medium;
• means for moving at least one of the transducer and the medium to provide a relative movement between the transducer and the medium, the transducer being arranged relative to the medium such that a spacing separates the MR element from the medium;
• a read channel connected to the transducer to read a signal from the medium using the MR element;
• a filter, coupled to the read channel, for passing a thermal signal component of the signal, the thermal signal component representing a thermal response of the MR element;
• and
• a detector, coupled to the filter, for detecting a variation in the thermal signal component corresponding to a variation in a surface profile of the storage medium.

A method for processing a signal obtained from a storage medium using a magnetoresistive (MR) element, the method comprising the steps of:

• reading the signal from the storage medium using the MR element in proximity with the storage medium;
• modifying the signal such that a thermal component of the signal representing a thermal response of the MR element is degraded;
• and
• altering the modified signal to produce a restored thermal signal substantially representative of the thermal component of the signal read from the storage medium.

A signal processing apparatus for an information storage device including an information storage medium, comprising:

• a transducer including a magnetoresistive (MR) element in proximity with the storage medium;
• a circuit, coupled to the transducer, for modifying a signal read from the storage medium using the MR element such that a thermal component of the signal representing a thermal response of the MR element is degraded;
• and
• a filter, coupled to the circuit, for producing a restored thermal signal substantially representative of the thermal component of the signal read from the storage medium using the modified signal received from the circuit.

An information storage device, comprising:

• a storage medium;
• a transducer including a magnetoresistive (MR) element in proximity with the storage medium;
• means for moving at least one of the transducer and the medium to provide a relative movement between the transducer and the medium;
• a circuit, coupled to the transducer, for modifying a signal read from the storage medium using the MR element such that a thermal component of the signal representing a thermal response of the MR element is degraded;
• and
• a filter, coupled to the circuit, for producing a restored thermal signal substantially representative of the thermal component of the signal read from the storage medium using the modified signal received from the circuit.