Precedent and subsequent minor transitions to alleviate pulse crowding

Claim 3

In a magnetic recording apparatus as recited in claim 1 wherein said combining means includes a current summing network coupled to said means for producing precedent and subsequent minor current transitions, and a current source coupled to said current summing network which provides a current having an amplitude I L for producing a major current transition.

Claim 4

A method for improving the magnetic recording of digital data as recited in claim 1 further comprising the steps of sensing the occurrence of each major voltage transition, producing a precedent minor current transition of lower amplitude and opposite direction relative to each major voltage transition, delaying each major voltage transition, sensing the occurrence of each delayed major voltage transition, producing a subsequent minor current transition of lower amplitude and opposite direction relative to each delayed major voltage transition, producing a major current transition in response to each delayed major voltage transition, and combining said precedent, subsequent and major current transitions to form a composite current signal having a precedent transition, a major transition, and a subsequent transition portion.

Claim 5

In a magnetic recording apparatus as recited in claim 3 wherein said means for sensing the occurrence of a major voltage transition includes an exclusive-OR circuit.

Claim 6

A method for improving the magnetic recording of digital data as set forth in claim 3 wherein the step of producing a precedent minor current transition includes the step of gating a current source which provides an output current having an amplitude I M for a first predetermined period of time.

Claim 7

A method for improving the magnetic recording of digital data as set forth in claim 5 wherein the step of delaying each major voltage transition further comprises the step of delaying each major voltage transition for a period of time equal to that said first predetermined period of time.

Claim 8

A method for improving the magnetic recording of digital data as recited in claim 6 wherein the step of producing a subsequent minor current transition includes the step of gating a current source which provides an output current having an amplitude I H >I M for a second predetermined period of time which is longer than said first predetermined period of time.

Claim 9

In a magnetic recording apparatus including a magnetizable storage medium, means for encoding digital data in the form of major transitions from one voltage level to another, and means for producing a major transition in the amplitude and direction of current coupled to a recording head in accordance with each major voltage transition, an improvement in said magnetic recording apparatus comprising means responsive to said encoded digital data for producing precedent and subsequent minor current transitions of lower amplitude and opposite direction relative to each major current transition, and means for combining said precedent and subsequent minor current transitions with said corresponding major current transitions whereby the amplitude and duration of current coupled to said recording head in accordance with each of said transitions records corresponding digital data in said storage medium that will produce a readout pulse in accordance therewith having a narrower pulse width and improved symmetry thereby enabling increased packing density in the storage medium and enhancing the accuracy in reading out the recorded digital data.

Claim 10

In a magnetic recording apparatus including a magnetizable storage medium, means for encoding digital data in the form of major transitions from one voltage level to another, and means for producing a major transition in the amplitude and direction of current coupled to a recording head in accordance with each major voltage transition, an improvement in said magnetic recording apparatus comprising means responsive to said encoded digital data for producing precedent and subsequent minor current transitions of lower amplitude and opposite direction relative to each major current transition, and means for combining said precedent and subsequent minor current transitions with said corresponding major current transitions whereby the amplitude and duration of current coupled to said recording head in accordance with each of said transitions records corresponding digital data in said storage medium that will produce a readout pulse in accordance therewith having a narrower pulse width and improved symmetry thereby enabling increased packing density in the storage medium and enhancing the accuracy in reading out the recorded digital data.

Claim 11

In a magnetic recording apparatus as recited in claim 8 wherein said means for producing precedent and subsequent minor current transitions includes means coupled to said encoding means for sensing the occurrence of a major voltage transition.

Claim 12

In a magnetic recording apparatus as recited in claim 9 wherein said means for sensing the occurrence of a major voltage transition includes a one-shot multivibrator having a quasi-stable state for a first predetermined time period.

Claim 13

In a magnetic recording apparatus as recited in claim 10 wherein said means for producing precedent and subsequent minor current transitions includes a current source coupled to said sensing means which provides a current having an amplitude I M .

Claim 14

In a magnetic recording apparatus as recited in claim 10 wherein said means for producing precedent and subsequent minor current transitions includes means coupled to said encoding means for delaying the occurrence of said major voltage transitions a period of time equal to said first predetermined time period.

Claim 15

In a magnetic recording apparatus as recited in claim 12 wherein said means for producing precedent and subsequent minor current transitions further includes means coupled to said delay means for sensing the occurrence of said delayed major voltage transitions.

Claim 16

In a magnetic recording apparatus as recited in claim 13 wherein said means for sensing the occurrence of said delayed major voltage transitions includes a one-shot multivibrator having a quasi-stable state for a second period of time which is longer than said first predetermined period of time.

Claim 17

In a magnetic recording apparatus as recited in claim 13 wherein said means for producing precedent and subsequent minor current transitions further includes a current source coupled to said sensing means which provides a current having an amplitude I H >I M .