Self clocking speed tolerant magnetic recording method and apparatus

Claim 1

Apparatus for magnetically recording information bits at a predetermined uniform spacing on a card such as a credit card or the like as it is moved by hand past said apparatus; said card having a plurality of magnetic bit markers prerecorded thereon at said uniform spacing and having a track for magnetically storing said information bits thereon; said apparatus being comprised of; clocking means for generating clock pulses of a predetermined frequency; first counting means responsive to a first control signal to enter an initial state and thereafter count said clock pulses; second counting means responsive to a second control signal to load a selectable number and thereafter generate a reset signal indicating when said selectable number of said clock pulses have occurred; first flip-flop means for resetting in response to said reset signal, and for setting in response to a third control signal; read head means for generating a voltage pulse whenever any one of said bit markers lies thereunder as said card is moved by hand past said read head; second flip-flop means for setting in response to said voltage pulse, and resetting in response to a fourth control signal; control means responsive to the setting of said second flip-flop for generating all of said control signals and said selectable number as a fraction of the count in said first counter, said fraction being of a first or second value dependent upon whether a "1" bit or a "0" bit is to be written on said track; and writing means for writing magnetic flux on said track in one direction in response to said second flip-flop being set, and for writing said flux in an opposite direction in response to said second flip-flop being reset.