Data read-out system and apparatus useful for angular measurements
First Claim
1. In a system having an input of a group of least significant bits and one or more groups of higher significant bits which change state at one transition point of one of the least significant bits, apparatus for producing output date correlated to the system input free of transition ambiguities comprising:
- system output means;
means for coupling information correlated to the least significant bits to said system output means;
means for storing information correlated to the higher significant bits and for transferring said stored information to said system output means;
control circuit means responsive to the status of the least significant bits for controlling the information input into said storage means, said control circuit means generating a control signal in the presence of a first zone around the transition point and a transition reflecting signal in the presence of the transition point, said control circuit generating a load signal in the presence of a second zone removed from said first zone, said load signal operative to input higher significant bit correlated information into said storage means; and
commutation circuit means associated with said control circuit means and responsive to said control signal for disabling said storage means from receiving said higher significant bit correlated information and responsive to said transition reflecting signal for altering the information in said storage means.
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Abstract
Data acquired from a source such as a coded disc is processed so as to be free of ambiguities associated with boundary transitions where the data source produces groups of bits which have least significant ordering and higher significant ordering. Wherever a common transition boundary between the bit groups occurs, ambiguities from misalignment of these boundaries are avoided by controlling the higher ordered bit transitions from the lower ordered bit transitions. Circuitry tracks and stores the higher order bits by synchronous updating whenever no misalignment or skew sensitive transitions are encountered. Logic circuitry continuously inspects the lower significant bits to determine the presence or absence of a zone surrounding the common transition boundary and also detects the actual passage and direction of the transition boundary in the lower significant bit group. This logic corrects the counter stored higher order bit counts in conformity with the status of the lower significant bit states. The system output is a composite of the lower significant digits read directly and the controlled and updated higher significant digits with appropriate code conversion. Whenever the data source is an optical coded disc or the like, the data acquired can be enhanced by an arrangement of light collimating and focusing elements relative to the coded transparent/opaque areas of the disc cell tracks.
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Citations
19 Claims
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1. In a system having an input of a group of least significant bits and one or more groups of higher significant bits which change state at one transition point of one of the least significant bits, apparatus for producing output date correlated to the system input free of transition ambiguities comprising:
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system output means; means for coupling information correlated to the least significant bits to said system output means; means for storing information correlated to the higher significant bits and for transferring said stored information to said system output means; control circuit means responsive to the status of the least significant bits for controlling the information input into said storage means, said control circuit means generating a control signal in the presence of a first zone around the transition point and a transition reflecting signal in the presence of the transition point, said control circuit generating a load signal in the presence of a second zone removed from said first zone, said load signal operative to input higher significant bit correlated information into said storage means; and commutation circuit means associated with said control circuit means and responsive to said control signal for disabling said storage means from receiving said higher significant bit correlated information and responsive to said transition reflecting signal for altering the information in said storage means. - View Dependent Claims (2, 3, 4)
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5. In a system having an input of a plurality of groups of binary bits with a first of the groups corresponding to a least significant order of information and one or more of the other groups corresponding to higher significant orders of information correlated to the least significant order group and wherein a first of the least significant bits changes binary state at points where at least one of the higher ordered groups changes binary state and a second of the least significant bits has a constant first binary state at the first bit binary state change point and a constant second binary state between the first bit binary state change points, apparatus for producing accurate output information comprising:
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a plurality of output terminals, means responsive to the first group of binary bits for coupling the information thereof to said output terminals, counter circuit means having an output relfective of the contents thereof and operable in a first mode for conforming said contents in response to signals at a first input thereof and in a second mode for changing the state of said contents in response to signals at a second input thereof, means responsive to the higher significant order group bits for coupling the information thereof to said counter circuit means first input, commutation means responsive to the first and second binary states of the second least significant bit for enabling said counter circuit means for said second and first mode operation, respectively, control means responsive to a binary state change of the first least significant bit for introducing an input signal to said counter circuit means second input, and means for connecting said counter circuit means output to said output terminals. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A system for providing accurate information concerning the angular displacement of a body relative to a reference line comprising:
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a disc mounted for accommodating rotary motion thereof relative to the body and having a plurality of radial tracks each having a plurality of groups of cells with said cells containing coded information corresponding to angular displacement from the reference line, said groups in each track including a first group having bits corresponding to a least significant digit with a first bit of said first group changing binary state at a transition boundary and a second bit of said first group having a first binary state for a zone around said transition boundary and a second binary state outside said zone, at least one of the other said groups having cells corresponding to a higher significant digit with the binary state of one cell thereof changing at said transition boundary, a plurality of means fixed relative to the body for sensing the binary state of said cells of each said track, a plurality of data latches connected to receive the outputs of respective said sensing means, a plurality of gate circuits, means interconnecting said data latch outputs to respective said gate circuits, a source of repetitively cycling sequential pulses, said data latches being responsive to a first said pulse for storing the outputs of said sensing means, timing circuit means responsive to the initial said first pulse after start-up of the system for producing a continuous output signal a predetermined time thereafter for enabling said plurality of gate circuits, commutation circuit means coupled for receiving the outputs of said data latches corresponding to the binary state of said first and second least significant bits and for producing first control signals outside of said zone, said commutation circuit being responsive to a second said sequential pulse for producing second control signals in the presence of said zone and the change in binary state of said least significant group first bit, counter circuit means having a first input coupled to the outputs of said gate circuits corresponding to said higher significant bits and a second input coupled to said commutation circuit means control signals, said counter circuit means responding to said first control signal by conforming the contents thereof to said first counter circuit means input and to said second control signals by ignoring said first input thereof and by changing the contents thereof when said first bit binary state changes, and output circuit means interconnected for receiving said gate circuit means outputs corresponding to said least significant group and the output of said counter circuit means. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification