Self-clocking multilevel data coding system

Claim 2

Data processing apparatus comprising input means for receiving a series of data input signals of two or more diffeRent types in successive data cells, output means for representing said input signals in coded form and actuable between three or more different significant states, and coding means responsive to said input signals to actuate said output means to said different states in accordance with a number of different code patterns each utilizing a selected plurality but not all of said states of the output means to represent said different types of input signals respectively, said coding means being operable in each of said cells to adopt a coding pattern which does not utilize to represent any of said types of input signals the same state of said output means actually produced in the preceding cell, said coding means including a switching matrix having input lines some of which receive said input signals, a plurality of flip-flops having outputs connected to additional ones of said input lines of said matrix and adapted when actuated to predetermined states to condition the matrix for use of said different code patterns respectively, means operable upon actuation of said output means to any particular one of said different states respectively to cause a corresponding one of said flip-flops to adopt a code pattern for the next cell which does not utilize said particular one of the states, and means responsive to each input signal received to apply a delayed clocking signal to all of said flipflops in a relation actuating them in delayed relation to each input signal to adopt a changed code pattern.

Claim 3

Data processing apparatus comprising input means for receiving a series of data input signals of two or more different types in successive data cells, output means for representing said input signals in coded form and actuable between three or more different significant states, and coding means responsive to said input signals to actuate said output means to said different states in accordance with a number of different code patterns each utilizing a selected plurality but not all of said states of the output means to represent said different types of input signals respectively, said coding means being operable in each of said cells to adopt a coding pattern which does not utilize to represent any of said types of input signals the same state of said output means actually produced in the preceding cell, said coding means including a switching matrix having input lines some of which receive said input signals, a plurality of flip-flops having outputs connected to additional ones of said input lines of said matrix and adapted when actuated to predetermined states to condition the matrix for use of said different code patterns respectively, means operable upon actuation of said output means to any particular one of said different states respectively to cause a corresponding one of said flip-flops to adopt a code pattern for the next cell which does not utilize said particular one of the states, and means responsive to each input signal received to apply a delayed clocking signal to all of said flip-flops in a relation actuating them in delayed relation to each input signal to adopt a changed code pattern, said output means including means for producing signals of predetermined different frequencies in said different states respectively, there being a magnetic recording head responsive to said different frequencies to produce corresponding changes in frequency modulation of an alternating magnetic record on a record track.

Claim 4

Data processing apparatus comprising input means for receiving a series of data input signals of two or more different types in successive data cells, output means for representing said input signals in coded form and actuable between three or more different significant states, and coding means responsive to said input signals to actuate said output means to said different states in accordance with a number of different code patterns each utilizing a selected plurality but not all of said states of the output means to represent said different types of input signals respectively, said coding means being operable in each of said cells to adopt a coding pattern which does not utilize to represent any of said types of input signals the same state of said output means actually produced in the preceding cell, said coding means including a switching matrix having input lines some of which receive said input signals, a plurality of flip-flops having outputs connected to additional ones of said input lines of said matrix and adapted when actuated to predetermined states to condition the matrix for use of said different code patterns respectively, means operable upon actuation of said output means to any particular one of said different states respectively to cause a corresponding one of said flip-flops to adopt a code pattern for the next cell which does not utilize said particular one of the states, and means responsive to each input signal received to apply a delayed clocking signal to all of said flip-flops in a relation actuating them in delayed relation to each input signal to adopt a changed code pattern, said output means including means for producing signals of predetermined different frequencies in said different states respectively, there being a magnetic recording head responsive to said different frequencies to produce corresponding changes in frequency modulation of an alternating magnetic record on a record track.