Method and apparatus for testing magnetic disc files

Claim 3

The method of claim 1 including the further step of measuring all the peak pairs and determining the number of measured pulse peak intervals which exceed a desired time interval.

Claim 4

The method of claim 1 including the further step of measuring all the peak pairs and determining the number of measured pulse peak intervals which are less than a desired time interval.

Claim 7

The method of claim 4 further comprising the steps of generating a reference signal proportional to the average peak amplitude of all the pulses of one polarity generated from said flux transitions, and comparing the peak amplitude of each pulse of said one polarity with said reference signal to indicate any abnormal difference in the amplitude relative to the average.

Claim 8

The method of claim 4 further including the steps of counting the number of pulse pairs having an abnormal peak spacing.

Claim 9

The method of claim 6 further including the steps of separately counting the number of pulse pairs exceeding a predetermined time standard and counting the number of pulse pairs falling below a predetermined time standard.

Claim 10

Apparatus for testing the performance characteristics of a magnetic recording system having one or more tracks on a recording medium on which binary information can be recorded and played back, comprising signal generating means for periodically generating rectangular pulses of predetermined duration corresponding to the minimum binary bit recording interval of the recording system, means coupled to the output of the said generating means for recording the pulses on any selected track on the disc in the form of a change in flux polarity at the leading and trailing edges of each pulse, playback means responsive to the changes in flux level on the track for generating a pulse in response to each flux change, means responsive to the pulses from said playback means for generating a timing signal indicating the time interval between the amplitude peaks of each pair of pulses generated by the playback means, and means responsive to said timing signal providing an indication whenever said time duration is not within predetermined limits.

Claim 11

Apparatus for testing the performance characteristics of a magnetic recording system having one or more tracks on a recording medium on which binary information can be recorded and played back, comprising signal generating means for periodically generating rectangular pulses of predetermined duration corresponding to the minimum binary bit recording interval of the recording system, means coupled to the output of the said generating means for recording the pulses on any selected track on the disc in the form of a change in flux polarity at the leading and trailing edges of each pulse, playback means responsive to the changes in flux level on the track for generating a pulse in response to each flux change, means responsive to the pulses from said playback means for generating a timing signal indicating the time interval between the amplitude peaks of each pair of pulses generated by the playback means, and means responsive to said timing signal providing an indication whenever said time duration is not within predetermined limits.

Claim 12

Apparatus as defined in claim 8 including means responsive to said indicating means for counting each time said time duration is not within said predetermined limits.

Claim 13

Apparatus as defined in claim 9 wherein said counting means includes means for separately counting each time said time duration exceeds a predetermined time interval.

Claim 14

Apparatus as defined in claim 9 wherein said counting means includes means for separately counting each time said time duration falls below a predetermined time interval.

Claim 15

Apparatus as defined in claim 9 further including means responsive to the pulses from said playback means for generating a signal proportional to the average peak amplitude of the pulses derived from one track, and comparing means responsive to the peak amplitude of the pulses from said playback means for indicating when the peak amplitude of any of said pulses differs from the average peak amplitude by a predetermined amount.

Claim 16

Apparatus as defined in claim 12 further including means responsive to said comparing means for counting each time a pulse exceeds said predetermined amount.

Claim 17

Testing apparatus for testing the performance characteristics of each of the digital recording tracks of multiple track magnetic disc file in which each track has associated therewith transducer means for recording and reproducing binary signals on the disc, said apparatus including signal generating means synchronized with rotation of the disc for generating a test signal, the test signal having a wave form which produces a pair of closely spaced flux transitions at spaced intervals along a selected track on the disc when applied to the transducer means, means for coupling the output of the signal generating means to each of the transducer means in succession, means coupled to each of the transducing means in succession for generating an output signal in response to the test signal recorded thereon, the output signal comprising a pair of pulses for each pair of flux transitions passing a transducing head, means sensing the time duration between peaks of each of said pair of pulses, and error indicating means indicating when said time duration between pairs of pulse peaks is outside predetermined limits.

Claim 18

Testing apparatus for testing the performance characteristics of each of the digital recording tracks of multiple track magnetic disc file in which each track has associated therewith transducer means for recording and reproducing binary signals on the disc, said apparatus including signal generating means synchronized with rotation of the disc for generating a test signal, the test signal having a wave form which produces a pair of closely spaced flux transitions at spaced intervals along a selected track on the disc when applied to the transducer means, means for coupling the output of the signal generating means to each of the transducer means in succession, means coupled to each of the transducing means in succession for generating an output signal in response to the test signal recorded thereon, the output signal comprising a pair of pulses for each pair of flux transitions passing a transducing head, means sensing the time duration between peaks of each of said pair of pulses, and error indicating means indicating when said time duration between pairs of pulse peaks is outside predetermined limits.

Claim 19

Apparatus as defined in claim 14 further including means responsive to said error indicating means for interrupting the successive coupling of said output signal generating means, whereby the output signal generating means remains coupled to the transducer means associated with a track producing an error.