Method and apparatus for storing and retrieving information by analog waveform correlation techniques

Claim 3

The method of claim 1 wherein the step of generating unique sets of sample signals is achieved by simultaneously detecting the amplitudes of the critical points on said corresponding discrete waveform.

Claim 4

The method of claim 1 comprising the further step of converting said output signal into a plurality of digit signals, each of said digit signals representing a bit configuration corresponding to said particular group of binary digits.

Claim 5

The method of claim 1 wherein the step of producing one discrete wavefoRm is achieved by sensing said pattern of representations and producing one discrete waveform corresponding to each of eight groups of binary digits having decimal digit values of from 0 to 7, each of said groups being one of eight triplets of binary digits; the step of generating unique sets of sample signals is achieved by detecting the amplitudes of the critical points on eight corresponding discrete waveforms, each of said unique sets corresponding to one of said eight discrete waveforms; and the step of generating a sum signal is achieved by the summation of the sample signals in a particular one of said unique sets, said sum signal corresponding in magnitude to the summation of the sample signals in said particular unique set and said unique sets corresponding to eight sum signals progressively increasing in magnitude by equal increments.

Claim 6

The method of claim 4 wherein the step of generating a sum signal is achieved by summing and amplifying the sample signals in a particular one of said unique sets, said sum signal corresponding in magnitude to the amplified summation of the sample signals in said particular unique set and said eight sum signals progressively increasing in magnitude by equal increments corresponding to said known digital values.

Claim 7

The method of claim 4 wherein the step of generating a sum signal is achieved by summing and amplifying the sample signals in a particular one of said unique sets, each sample signal in said particular unique set being amplified by one of a plurality of predetermined weighting factors, said sum signal corresponding in magnitude to the amplified summation of the sample signals in said particular unique set and said eight sum signals progressively increasing in magnitude by equal increments of unity digital value.

Claim 8

An information storage system wherein binary information is stored in a record medium in a pattern of representations corresponding to a succession of groups of binary digits, comprising in combination: sensing means for sensing said pattern of representations and for producing an electrical signal having one discrete waveform corresponding to each of said groups of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform and providing a corresponding unique set of sample signals for each discrete waveform, each sample signal in each unique set being directly related in magnitude to the amplitude of a critical point on said discrete waveform; and summing means for receiving each unique set of sample signals and for providing in response to each unique set a sum signal corresponding in magnitude to the summation of the amplitudes of the sample signals in each unique set said sum signal representing a pattern of representations sensed.

Claim 9

An information storage system wherein binary information is stored in a record medium in a pattern of representations corresponding to a succession of groups of binary digits, comprising in combination: sensing means for sensing said pattern of representations and for producing an electrical signal having one discrete waveform corresponding to each of said groups of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform and providing a corresponding unique set of sample signals for each discrete waveform, each sample signal in each unique set being directly related in magnitude to the amplitude of a critical point on said discrete waveform; and summing means for receiving each unique set of sample signals and for providing in response to each unique set a sum signal corresponding in magnitude to the summation of the amplitudes of the sample signals in each unique set said sum signal representing a pattern of representations sensed.

Claim 10

The system of claim 7 further comprising a selection means for selecting from a plurality of ranges of compare signals progressively increasing in magnitude by increments corresponding to known digital values that particular range most closely corresponding to the magnitude of said sum signal and providing in response to the selection an output signal corresponding to a particular group of binary digits.

Claim 11

The system of claim 7 wherein said information storage system is a magnetic storage system, said representations are presences and absences of transitions in said record medium and said groups are triplets.

Claim 12

A magnetic storage system wherein binary information is recorded in a medium in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, each of said triplets being one of eight triplets of binary digits having decimal digit values of from 0 to 7, comprising in combination: sensing means for sensing said pattern of presences and absences of transitions and producing an electrical signal having eight discrete waveforms, one of said eight discrete waveforms corresponding to each of said eight triplets of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on each one of said eight discrete waveforms successively and for successively providing a corresponding one of eight unique sets of sample signals for each discrete waveform, each sample signal in each one of said eight unique sets being directly related in magnitude to the amplitude of a critical point on said one of said eight discrete waveforms; and summing means for receiving each one of said eight unique sets successively and for successively providing in response to each one of said eight unique sets a particular one of eight sum signals corresponding in magnitude to the summation of the amplitudes of the sample signals in said one of said eight unique sets, said eight sum signals progressively increasing in magnitude by equal increments directly related to known digital values and said particular one of said eight sum signals representing a pattern of presences and absences of transitions sensed.

Claim 13

A magnetic storage system wherein binary information is recorded in a medium in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, each of said triplets being one of eight triplets of binary digits having decimal digit values of from 0 to 7, comprising in combination: sensing means for sensing said pattern of presences and absences of transitions and producing an electrical signal having eight discrete waveforms, one of said eight discrete waveforms corresponding to each of said eight triplets of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on each one of said eight discrete waveforms successively and for successively providing a corresponding one of eight unique sets of sample signals for each discrete waveform, each sample signal in each one of said eight unique sets being directly related in magnitude to the amplitude of a critical point on said one of said eight discrete waveforms; and summing means for receiving each one of said eight unique sets successively and for successively providing in response to each one of said eight unique sets a particular one of eight sum signals corresponding in magnitude to the summation of the amplitudes of the sample signals in said one of said eight unique sets, said eight sum signals progressively increasing in magnitude by equal increments directly related to known digital values and said particular one of said eight sum signals representing a pattern of presences and absences of transitions sensed.

Claim 14

A magnetic storage system wherein self-clocking binary information is recorded in a medium along a track in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, each of said triplets being recorded in the next four successive transition positions in said track following the four transition positions in which the pattern representing the preceding triplet of binary digits is recorded in a manner such that no more than two sequential transition positions occur without a transition whereby different combinations of presences and absences of transitions in four successive positions along said track correspond to different triplets of binary digits, comprising in combination: sensing means for detecting magnetic flux that is representative of the pattern of presences and absences of said transitions in each of said four successive positions along said track and for producing an electrical signal having one discrete waveform corresponding to each of said triplets of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform and providing a corresponding unique set of sample signals for each discrete waveform; a summing means for receiving each unique set of sample signals and being responsive to each unique set of sample signals to provide a sum signal having a magnitude directly related to the summation of the amplitudes of each unique set; and selection means for selecting from a plurality of ranges of compare signals progressively increasing in magnitude by increments corresponding to known digital values, that particular range most closely corresponding to the magnitude of said sum signal and in response to the comparison providing an output signal corresponding to a particular pattern of presences and absences of transitions in each of said four successive positions sensed.

Claim 15

A magnetic storage system wherein self-clocking binary information is recorded in a medium along a track in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, each of said triplets being recorded in the next four successive transition positions in said track following the four transition positions in which the pattern representing the preceding triplet of binary digits is recorded in a manner such that no more than two sequential transition positions occur without a transition whereby different combinations of presences and absences of transitions in four successive positions along said track correspond to different triplets of binary digits, comprising in combination: sensing means for detecting magnetic flux that is representative of the pattern of presences and absences of said transitions in each of said four successive positions along said track and for producing an electrical signal having one discrete waveform corresponding to each of said triplets of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform and providing a corresponding unique set of sample signals for each discrete waveform; a summing means for receiving each unique set of sample signals and being responsive to each unique set of sample signals to provide a sum signal having a magnitude directly related to the summation of the amplitudes of each unique set; and selection means for selecting from a plurality of ranges of compare signals progressively increasing in magnitude by increments corresponding to known digital values, that particular range most closely corresponding to the magnitude of said sum signal and in response to the comparison providing an output signal corresponding to a particular pattern of presences and absences of transitions in each of said four successive positions sensed.

Claim 16

A magnetic storage system wherein self-clocking binary information is recorded in a medium along a track in a succession of triplets of binary digits, each of said triplet being recorded in the next four successive transition positions in said track following the four transition positions in which the pattern representing the preceding triplet of binary digits is recorded in a manner such that no more than two sequential transition positions occur without a transition whereby different combinations of presences and absences of transitions in four successive positions along said track correspond to different ones of eight triplets of binary digits, comprising in combination: sensing means for detecting magnetic flux that is representative of the pattern of presences and absences of said transitions in each of said four successive positions along said track and for producing an electrical signal having eight discrete waveforms, one of said eight discrete waveforms corresponding to each of said eight triplets of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on each one of said eight discrete waveforms successively and for successively providing a corresponding one of eight unique sets of sample signals for each of said eight discrete waveforms, each sample signal in each of said eight unique sets being directly related in magnitude to the amplitude of a critical point on said one of said eight discrete waveforms; a summing means for receiving each one of said eight unique sets successively and for successively providing in response to each one of said eight unique sets a particular one of eight sum signals corresponding in magnitude to the summation of the amplitudes of the sample signals in said one of said eight unique sets, said eight sum signals progressively increasing in magnitude by equal increments; and selection means for selecting from a plurality of ranges of compare signals progressively increasing in magnitude by increments corresponding to known digital values, that particular range most closely corresponding to the magnitude of said particular one of eight sum signals and in response to the comparison providing an output signal corresponding to a particular pattern of presences and absences of transitions in each of said four successive positions sensed.

Claim 17

A magnetic storage system wherein self-clocking binary information is recorded in a medium along a track in a succession of triplets of binary digits, each of said triplet being recorded in the next four successive transition positions in said track following the four transition positions in which the pattern representing the preceding triplet of binary digits is recorded in a manner such that no more than two sequential transition positions occur without a transition whereby different combinations of presences and absences of transitions in four successive positions along said track correspond to different ones of eight triplets of binary digits, comprising in combination: sensing means for detecting magnetic flux that is representative of the pattern of presences and absences of said transitions in each of said four successive positions along said track and for producing an electrical signal having eight discrete waveforms, one of said eight discrete waveforms corresponding to each of said eight triplets of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on each one of said eight discrete waveforms successively and for successively providing a corresponding one of eight unique sets of sample signals for each of said eight discrete waveforms, each sample signal in each of said eight unique sets being directly related in magnitude to the amplitude of a critical point on said one of said eight discrete waveforms; a summing means for receiving each one of said eight unique sets successively and for successively providing in response to each one of said eight unique sets a particular one of eight sum signals corresponding in magnitude to the summation of the amplitudes of the sample signals in said one of said eight unique sets, said eight sum signals progressively increasing in magnitude by equal increments; and selection means for selecting from a plurality of ranges of compare signals progressively increasing in magnitude by increments corresponding to known digital values, that particular range most closely corresponding to the magnitude of said particular one of eight sum signals and in response to the comparison providing an output signal corresponding to a particular pattern of presences and absences of transitions in each of said four successive positions sensed.

Claim 18

The combination set forth in claim 12 wherein said eight sum signals progressively increase in magnitude by unity increments.

Claim 19

A magnetic storage system wherein binary information is recorded in a medium along a track in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, comprising in combination: binary means for sensing magnetic flux representative of the pattern of presences and absences of said transitions and for producing an electrical signal having one discrete waveform corresponding to each of said triplets of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform, said sampling means having an input terminal for receiving each discrete waveform and a plurality of output terminals for simultaneously delivering a corresponding unique set of sample signals for each discrete waveform, each sample signal in each unique set being directly related in magnitude to the amplitude of a critical point on said discrete waveform; a correlation network including a current-summing means and a plurality of impedance means, one of said impedance means connected between each one of certain of said output terminals and said current-summing means, the quantity of impedance of the impedance means between each one of said certain terminals and said summing means being of a quantity to weight each sample signal applied through one of said impedance means to said current-summing means by a predetermined weighting factor, said current-summing means receiving each unique set of weighted sample signals and for providing in response to each unique set a sum signal directly related in magnitude to the summation of the amplitudes of the sample signals in each unique set; and selection means for selecting from a plurality of ranges of compare signals progressively increasing in magnitude by increments corresponding to known digital values, that particular range most closely corresponding to the magnitude of said sum signal, and providing in response to the comparison an output signal corresponding to a particular triplet of digits.

Claim 20

A magnetic storage system wherein binary information is recorded in a medium along a track in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, comprising in combination: binary means for sensing magnetic flux representative of the pattern of presences and absences of said transitions and for producing an electrical signal having one discrete waveform corresponding to each of said triplets of binary digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform, said sampling means having an input terminal for receiving each discrete waveform and a plurality of output terminals for simultaneously delivering a corresponding unique set of sample signals for each discrete waveform, each sample signal in each unique set being directly related in magnitude to the amplitude of a critical point on said discrete waveform; a correlation network including a current-summing means and a plurality of impedance means, one of said impedance means connected between each one of certain of said output terminals and said current-summing means, the quantity of impedance of the impedance means between each one of said certain terminals and said summing means being of a quantity to weight each sample signal applied through one of said impedance means to said current-summing means by a predetermined weighting factor, said current-summing means receiving each unique set of weighted sample signals and for providing in response to each unique set a sum signal directly related in magnitude to the summation of the amplitudes of the sample signals in each unique set; and selection means for selecting from a plurality of ranges of compare signals progressively increasing in magnitude by increments corresponding to known digital values, that particular range most closely corresponding to the magnitude of said sum signal, and providing in response to the comparison an output signal corresponding to a particular triplet of digits.

Claim 21

The combination set forth in claim 14 wherein an even number of said sample signals are delivered in each unique set and one of said impedance means are connected between each one of a first plurality of said output terminals and a negative input terminal of said summing means and one of said impedance means is connected between each one of a second plurality of said output terminals and a positive input terminal of said summing means, said first second plurality of said output terminals beIng equal in number whereby noise signals common to each of said output, positive input and negative input terminals are cancelled.

Claim 22

The combination set forth in claim 14 wherein one of a first plurality of said impedance means is connected between each one of a first plurality of said output terminals and a negative input terminal of said summing means; one of a second plurality of said impedance means is connected between each one of a second plurality of said impedance means is connected between each one of a second plurality of said output terminals and a positive input terminal of said summing means; and the quantity of impedance of each one of first plurality and second plurality of said impedance means being of a quantity to weight a sample signal applied through one said first plurality of said impedance means to said positive input terminal by a weighting factor of +1 and to weight a sample signal applied through one of said second plurality of said impedance means to said negative input terminal by a weighting factor of -1.

Claim 23

A magnetic storage system wherein binary information is recorded in a medium along a track in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, comprising in combination: sensing means for detecting magnetic flux that is representative of the pattern of presences and absences of said transitions and for producing in response to said transitions an electrical signal having one discrete waveform corresponding to each of said triplets of digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform, and providing a corresponding unique set of sample signals for each discrete waveform, each sample signal in each unique set being directly related in magnitude to the amplitude of a critical point on said discrete waveform; a correlation network including a current-summing means for receiving each unique set of sample signals and being responsive to each unique set of sample signals for providing a sum signal corresponding in magnitude to the summation of the amplitudes of the sample signals in each unique set; a plurality of threshold means, each of said threshold means receiving said sum signal and responding to a sum signal having a magnitude within a predetermined range of threshold levels to provide an output signal, said range within which each of said plurality of threshold means responds progressively increasing in magnitude by increments corresponding to known digital values; a selector for receiving said output signal from each of said threshold means responding, said selector selecting the one of said output signals corresponding to that particular range most closely corresponding to the magnitude of said sum signal and providing in response to the selection a selected signal corresponding to a particular triplet of digits sensed; and conversion means for receiving said selected signal and responding to said selected signal to provide a plurality of digit signals representing a particular triplet of digits.

Claim 24

A magnetic storage system wherein binary information is recorded in a medium along a track in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, comprising in combination: sensing means for detecting magnetic flux that is representative of the pattern of presences and absences of said transitions and for producing in response to said transitions an electrical signal having one discrete waveform corresponding to each of said triplets of digits; sampling means for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform, and providing a corresponding unique set of sample signals for each discrete waveform, each sample signal in each unique set being directly related in magnitude to the amplitude of a critical point on said discrete waveform; a correlation network including a current-summing means for receiving each unique set of sample signals and being responsive to each unique set of sample signals for providing a sum signal corresponding in magnitude to the summation of the amplitudes of the sample signals in each unique set; a plurality of threshold means, each of said threshold means receiving said sum signal and responding to a sum signal having a magnitude within a predetermined range of threshold levels to provide an output signal, said range within which each of said plurality of threshold means responds progressively increasing in magnitude by increments corresponding to known digital values; a selector for receiving said output signal from each of said threshold means responding, said selector selecting the one of said output signals corresponding to that particular range most closely corresponding to the magnitude of said sum signal and providing in response to the selection a selected signal corresponding to a particular triplet of digits sensed; and conversion means for receiving said selected signal and responding to said selected signal to provide a plurality of digit signals representing a particular triplet of digits.

Claim 25

A magnetic storage system wherein self-clocking binary information is recorded in a medium along a track in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, each of said triplets being recorded in the next four successive transition positions of a cell in said track following the four transition positions of a cell in which the pattern representing the preceding triplet of binary digits is recorded in a manner such that no more than two sequential transition positions occur without a transition whereby different combinations of presences and absences of transitions in four successive positions along said track correspond to eight triplets of binary digits having decimal digit values of from 0 to 7 comprising in combination: sensing means for detecting magnetic flux that is rEpresentative of the pattern of presences or absences of said transitions in each of said four successive positions along said track and for producing in response to said transitions an electrical signal having eight discrete waveforms, one of said eight discrete waveforms corresponding to each of said triplets of binary digits; a delay line for receiving said discrete waveform and for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform, said delay line having an input terminal for receiving any one of said eight discrete waveforms successively and a plurality of output terminals for successively and simultaneously delivering a corresponding one of eight unique sets of sample signals for each discrete waveform, at least one of said sample signals of each one of said unique sets being of a positive polarity with respect to a reference level and at least one of said samples of each one of said unique sets being of a negative polarity with respect to said reference level, and each sample signal in each one of said eight unique sets being directly related in magnitude to the amplitude of a critical point on said one of said eight discrete waveforms; a correlation network including a current-summing amplifier having a positive and a negative input terminal, an output terminal, and one of a first plurality of impedance elements connected between each one of a first plurality of said output terminals and said positive input terminal, and one of a second plurality of impedance elements connected between each one of a second plurality of said output terminals and the negative input terminal, the quantity of impedance of each of said first and second plurality of impedance elements being substantially equal for weighting each sample signal of said eight discrete waveforms by a predetermined weighting factor, said current-summing amplifier successively receiving each one of said unique sets of weighted sample signals and successively delivering at its output terminal in response to each one of said eight unique sets one of eight sum signals, a particular one of said eight sum signals being proportional in magnitude to the summation of the amplitudes of the sample signals in said one of said eight unique sets of weighted sample signals applied through said first and second plurality of impedance elements to said positive and negative input terminals to effectively cancel noise signals common to each sample signal of each one of said eight unique sets, and said eight sum signals progressively increasing in magnitude by equal increments; a polarity detection means for receiving said sample signals and for detecting in response to said sample signals the presence of a sample signal having a negative polarity representative of a transition at a fourth transition position in any four successive positions corresponding to one of said eight triplets and for providing in response to the detecting of said negative polarity representation an invert signal; gating means for receiving said sum signal and said invert signal and being responsive during the presence of said invert signal to invert the polarity of said sum signal for providing an inverted sum signal and being responsive during the absence of said invert signal for providing said sum signal; a plurality of threshold means, each of said threshold means receiving said inverted sum signal and said sum signal and responding to an inverted sum signal and a sum signal having a magnitude within a predetermined range of threshold levels to provide an output signal, said range within which each of said plurality of threshold means responds progressively increasing in magnitude by increments corresponding to known digital values; a selector for receiving said output signal from each of said threshold means responding and being responsive for selecting the one of said output signals corresponding to that particular range most closely corresponding to the magnitude of said sum signaL and providing in response to the selection a selected signal; and a converter for receiving said selected signal and responding to said selected signal to provide a plurality of digit signals representing one of said eight triplets of digits corresponding to the particular pattern of presences and absence of transitions sensed.

Claim 26

A magnetic storage system wherein self-clocking binary information is recorded in a medium along a track in a pattern of presences and absences of transitions corresponding to a succession of triplets of binary digits, each of said triplets being recorded in the next four successive transition positions of a cell in said track following the four transition positions of a cell in which the pattern representing the preceding triplet of binary digits is recorded in a manner such that no more than two sequential transition positions occur without a transition whereby different combinations of presences and absences of transitions in four successive positions along said track correspond to eight triplets of binary digits having decimal digit values of from 0 to 7 comprising in combination: sensing means for detecting magnetic flux that is rEpresentative of the pattern of presences or absences of said transitions in each of said four successive positions along said track and for producing in response to said transitions an electrical signal having eight discrete waveforms, one of said eight discrete waveforms corresponding to each of said triplets of binary digits; a delay line for receiving said discrete waveform and for simultaneously detecting amplitudes at a plurality of critical points on said discrete waveform, said delay line having an input terminal for receiving any one of said eight discrete waveforms successively and a plurality of output terminals for successively and simultaneously delivering a corresponding one of eight unique sets of sample signals for each discrete waveform, at least one of said sample signals of each one of said unique sets being of a positive polarity with respect to a reference level and at least one of said samples of each one of said unique sets being of a negative polarity with respect to said reference level, and each sample signal in each one of said eight unique sets being directly related in magnitude to the amplitude of a critical point on said one of said eight discrete waveforms; a correlation network including a current-summing amplifier having a positive and a negative input terminal, an output terminal, and one of a first plurality of impedance elements connected between each one of a first plurality of said output terminals and said positive input terminal, and one of a second plurality of impedance elements connected between each one of a second plurality of said output terminals and the negative input terminal, the quantity of impedance of each of said first and second plurality of impedance elements being substantially equal for weighting each sample signal of said eight discrete waveforms by a predetermined weighting factor, said current-summing amplifier successively receiving each one of said unique sets of weighted sample signals and successively delivering at its output terminal in response to each one of said eight unique sets one of eight sum signals, a particular one of said eight sum signals being proportional in magnitude to the summation of the amplitudes of the sample signals in said one of said eight unique sets of weighted sample signals applied through said first and second plurality of impedance elements to said positive and negative input terminals to effectively cancel noise signals common to each sample signal of each one of said eight unique sets, and said eight sum signals progressively increasing in magnitude by equal increments; a polarity detection means for receiving said sample signals and for detecting in response to said sample signals the presence of a sample signal having a negative polarity representative of a transition at a fourth transition position in any four successive positions corresponding to one of said eight triplets and for providing in response to the detecting of said negative polarity representation an invert signal; gating means for receiving said sum signal and said invert signal and being responsive during the presence of said invert signal to invert the polarity of said sum signal for providing an inverted sum signal and being responsive during the absence of said invert signal for providing said sum signal; a plurality of threshold means, each of said threshold means receiving said inverted sum signal and said sum signal and responding to an inverted sum signal and a sum signal having a magnitude within a predetermined range of threshold levels to provide an output signal, said range within which each of said plurality of threshold means responds progressively increasing in magnitude by increments corresponding to known digital values; a selector for receiving said output signal from each of said threshold means responding and being responsive for selecting the one of said output signals corresponding to that particular range most closely corresponding to the magnitude of said sum signaL and providing in response to the selection a selected signal; and a converter for receiving said selected signal and responding to said selected signal to provide a plurality of digit signals representing one of said eight triplets of digits corresponding to the particular pattern of presences and absence of transitions sensed.