Apparatus and method for acquiring and detecting stale data
First Claim
Patent Images
1. Apparatus for data acquisition, comprising:
- input means for supplying input signals representing occurrences of events;
timing data generating means for generating cyclical timing data counts comprised of (n+m) bits, wherein n and m are integers;
latching means responsive to each occurrence of an input signal for latching the timing data count when the input signal occurs and for storing said timing data count as a time character with an associated validity flag;
stale data processing means responsive to a timing data count and at least one of the m bits of a stored time character for testing if said stored time character was produced during a previous cycle of said timing data counts;
flag setting means for setting the validity flag associated with each stored time character produced during a previous cycle of said timing data counts, thereby identifying a stale stored time character; and
reading means for reading out those stored time characters from said storing means which are not identified as stale stored time characters and including means for establishing a read out time, and comparison means responsive to a timing data count and to a stored time character then being read out at a read out time for setting the validity flag associated with said read out time character if said read out time character was captured during a timing data count cycle previous to the timing data count cycle at said read out time to thereby identify a stale read out time character.
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Abstract
Stale data is detected in a shift register containing time characters representing event occurrence times, expressed in timing data counts of a cyclic counter, by comparing the most significant bit of each stored time character with a value based on the most significant bits of a current timing data count. A stale stored time character is disposed of by setting its associated validity flag, which indicates that the time character is not to be read out of the shift register.
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Citations
21 Claims
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1. Apparatus for data acquisition, comprising:
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input means for supplying input signals representing occurrences of events; timing data generating means for generating cyclical timing data counts comprised of (n+m) bits, wherein n and m are integers; latching means responsive to each occurrence of an input signal for latching the timing data count when the input signal occurs and for storing said timing data count as a time character with an associated validity flag; stale data processing means responsive to a timing data count and at least one of the m bits of a stored time character for testing if said stored time character was produced during a previous cycle of said timing data counts; flag setting means for setting the validity flag associated with each stored time character produced during a previous cycle of said timing data counts, thereby identifying a stale stored time character; and reading means for reading out those stored time characters from said storing means which are not identified as stale stored time characters and including means for establishing a read out time, and comparison means responsive to a timing data count and to a stored time character then being read out at a read out time for setting the validity flag associated with said read out time character if said read out time character was captured during a timing data count cycle previous to the timing data count cycle at said read out time to thereby identify a stale read out time character.
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2. Apparatus for data acquisition, comprising:
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input means for supplying input signals representing occurrences of events; timing data generating means for generating cyclical timing data counts comprised of (n+m) bits, wherein n and m are integers, including periodic disposal signal generating means responsive to a cyclical timing data count for generating a periodic disposal signal; latching means responsive to each occurrence of an input signal for latching the timing data count when the input Signal occurs and for storing said timing data count as a time character with an associated validity flag; stale data processing means including testing means responsive to said periodic disposal signal and at least one of the m bits of a stored time character for testing if said stored time character was produced during a previous cycle of said timing data counts; and flag setting means for setting the validity flag associated with each stored time character produced during a previous cycle of said timing data counts, thereby identifying a stale stored time character. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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9. Apparatus for data acquisition, comprising:
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a plurality of input means, each for supplying input signals representing occurrences of events; common timing data generating means for generating cyclical timing data counts comprised of (n+m) bits, wherein n and m are integers; a plurality of latching means, each coupled to a respective input means and to said common timing data generating means for latching the timing data count upon the occurrence of an input signal and for storing said timing data count as a time character with an associated validity flag; a plurality of stale data processing means, each coupled to said common timing data generating means and a respective latching means, responsive to a timing data count and to at least one of the m bits of each of the time characters stored in said respective latching means for testing if the stored time characters were produced during a previous cycle of said timing data counts; a plurality of flag setting means, each for setting the validity flag associated with a stored time character produced during a previous cycle of said timing data counts, thereby identifying a stale stored time character; and a plurality of reading means, each coupled to a respective storage means for reading out those stored time characters from said respective storage means which are not identified as stale stored time characters, and each including means for establishing a common read out time, and comparison means responsive to a timing data count and to a stored time character then being read out at a read out time for setting the validity flag associated with said read out time character if said read out time character was captured during a timing data count cycle previous to the timing data count cycle at said read out time to thereby identify a stale read out time character.
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10. Apparatus for data acquisition, comprising:
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a plurality of input means, each for supplying input signals representing occurrences of events; common timing data generating means for generating cyclical timing data counts comprised of (n+m) bits, wherein n and m are integers, including periodic disposal signal generating means responsive to a cyclical timing data count for generating a periodic disposal signal; a plurality of latching means, each coupled to a respective input means and to said common timing data generating means for latching the timing data count upon the occurrence of an input signal and for storing said timing data count as a time character with an associated validity flag; a plurality of stale data processing means, each coupled to said common timing data generating means and a respective latching means, and each including a plurality of testing means, each responsive to said periodic disposal signal and at least one of the m bits of each of the time characters stored in said respective latching means for testing if the stored time character was produced during a previous cycle of said timing data counts; and a plurality of flag setting means, each for setting the validity flag associated with a stored time character produced during a previous cycle of said timing data counts, thereby identifying a stale stored time character. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of determining when stored time characters, which represent respective times of event occurrences, are stale, said time characters being formed of (n+m) bits of a timing data count generated by a cyclic timing data counter, said method comprising the steps of:
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sensing selected bits of a timing data count and at least one of the m bits of each of the stored time characters and generating first and second periodic disposal signals in response to said selected bits of said timing data count to define comparison periods; and setting a flag associated with each stored time character if the sensed bits of said timing data count and said stored time character have one of predetermined combinations of values, thereby indicating that said stored time character is a stale stored time character formed during a timing data count cycle prior to the timing data count cycle then generating said timing data count. - View Dependent Claims (18, 19, 20, 21)
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Specification