Digital programmable packet switch synchronizer

Claim 1

A method for detecting a unique digital word in a digital data stream, comprising the steps of: (a) storing a representative sample of said unique digital word; (b) storing a preset number of the most recently received data bits of said digital data stream; (c) receiving and storing a new data bit of said digital data stream in said most recently received data bits and displacing an oldest bit thereof; (d) in response to the storing of a new data bit, comparing a first bit of said unique digital word with an oldest bit of said most recently received data bits as modified in step (c); (e) repeating step (d) for each subsequent bit, from said first bit, of said unique digital word and each next oldest bit, from said oldest bit, of said most recently received bits as modified in step (c) until a last bit of said unique digital word has been compared to said new data bit; (f) evaluating the results of said comparisons to determine if the stored data stream bits correlate with the stored unique digital word bits exceeding a preset threshold; and (g) if said stored data stream bits do not correlate with the stored unique digital word bits exceeding the preset threshold, repeating steps (c)-(f); and (h) if said stored data stream bits do correlate with the stored unique digital word bits exceeding the preset threshold, generating an output signal to indicate detection of said unique digital word within said digital data stream.

Claim 2

A method for detecting a unique digital word in a digital data stream, comprising the steps of: (a) storing a representative sample of said unique digital word; (b) storing a preset number of the most recently received data bits of said digital data stream; (c) receiving and storing a new data bit of said digital data stream in said most recently received data bits and displacing an oldest bit thereof; (d) in response to the storing of a new data bit, comparing a first bit of said unique digital word with an oldest bit of said most recently received data bits as modified in step (c); (e) repeating step (d) for each subsequent bit, from said first bit, of said unique digital word and each next oldest bit, from said oldest bit, of said most recently received bits as modified in step (c) until a last bit of said unique digital word has been compared to said new data bit; (f) evaluating the results of said comparisons to determine if the stored data stream bits correlate with the stored unique digital word bits exceeding a preset threshold; and (g) if said stored data stream bits do not correlate with the stored unique digital word bits exceeding the preset threshold, repeating steps (c)-(f); and (h) if said stored data stream bits do correlate with the stored unique digital word bits exceeding the preset threshold, generating an output signal to indicate detection of said unique digital word within said digital data stream.

Claim 4

A method for detecting a unique digital data word in a digital data stream, comprising the steps of: storing a representative sample of said unique digital word; storing a preset number of the most recently received bits of said digital data stream; receiving and storing a concurrently received data bit of said digital data stream in said most recently received data bits and displacing an oldest bit thereof; receiving a blanker signal having a first state designating that the concurrently received bit of said digital data stream is valid and a second state designating that the concurrently received bit of the digital data stream is invalid; storing a blanker bit corresponding to each stored bit of said digital data stream, each blanker bit designating a valid or invalid state of the corresponding bit of said digital data stream; for each concurrently received bit, serially comparing the valid state stored data stream bits, beginning with an oldest bit thereof, with serial bits of the representative sample of said unique digital word, beginning with a first bit thereof, until the concurrently received bit of said most recently received bits has been compared to a last bit of said unique digital word, said comparisons occurring during a bit period of said digital data stream; evaluating the results of the step of serially comparing to determine if the stored data stream bits correlate with the stored unique digital word bits exceeding a preset threshold; counting the number of blanker bits which correspond to said stored digital data stream bits and indicate invalid states; and generating an output signal to indicate detection of said unique digital word when said correlation exceeds said preset threshold and the number of blanker bits does not exceed a preset limit.

Claim 5

A method for detecting a unique digital data word in a digital data stream, comprising the steps of: storing a representative sample of said unique digital word; storing a preset number of the most recently received bits of said digital data stream; receiving and storing a concurrently received data bit of said digital data stream in said most recently received data bits and displacing an oldest bit thereof; receiving a blanker signal having a first state designating that the concurrently received bit of said digital data stream is valid and a second state designating that the concurrently received bit of the digital data stream is invalid; storing a blanker bit corresponding to each stored bit of said digital data stream, each blanker bit designating a valid or invalid state of the corresponding bit of said digital data stream; for each concurrently received bit, serially comparing the valid state stored data stream bits, beginning with an oldest bit thereof, with serial bits of the representative sample of said unique digital word, beginning with a first bit thereof, until the concurrently received bit of said most recently received bits has been compared to a last bit of said unique digital word, said comparisons occurring during a bit period of said digital data stream; evaluating the results of the step of serially comparing to determine if the stored data stream bits correlate with the stored unique digital word bits exceeding a preset threshold; counting the number of blanker bits which correspond to said stored digital data stream bits and indicate invalid states; and generating an output signal to indicate detection of said unique digital word when said correlation exceeds said preset threshold and the number of blanker bits does not exceed a preset limit.

Claim 7

A method for detecting a unique digital word in a digital data stream, comprising the steps of: (a) storing a representative sample of said unique digital word; (b) storing a preset number of the most recently received data bits of said data stream; (c) receiving and storing a new data bit of said digital data stream in said most recently received data bits and displacing an oldest bit thereof; (d) in response to the storing of a new data bit, comparing a first bit of said unique digital word with an oldest bit of said most recently received data bits as modified in step (c); (e) repeating step (d) for each subsequent bit, from said first bit, of said unique digital word and each next oldest bit, from said oldest bit, of said most recently received bits as modified in step (c) until a last bit of said unique digital word has been compared to said new data bit; (f) counting a number of noncomparisons resulting from the comparisons in steps (d)-(e); (g) if the number count of said noncomparisons is greater than a preset threshold, repeating steps (c)-(f); (h) generating an output signal to indicate detection of said unique digital word when the number count of said noncomparisons is less than a preset threshold number.

Claim 8

A method for detecting a unique digital word in a digital data stream, comprising the steps of: (a) storing a representative sample of said unique digital word; (b) storing a preset number of the most recently received data bits of said data stream; (c) receiving and storing a new data bit of said digital data stream in said most recently received data bits and displacing an oldest bit thereof; (d) in response to the storing of a new data bit, comparing a first bit of said unique digital word with an oldest bit of said most recently received data bits as modified in step (c); (e) repeating step (d) for each subsequent bit, from said first bit, of said unique digital word and each next oldest bit, from said oldest bit, of said most recently received bits as modified in step (c) until a last bit of said unique digital word has been compared to said new data bit; (f) counting a number of noncomparisons resulting from the comparisons in steps (d)-(e); (g) if the number count of said noncomparisons is greater than a preset threshold, repeating steps (c)-(f); (h) generating an output signal to indicate detection of said unique digital word when the number count of said noncomparisons is less than a preset threshold number.

Claim 11

A method for detecting a unique digital word in a digital data stream, comprising the steps of: storing a representative sample of said unique digital word; storing a preset number of the most recently received bits of said digital data stream; receiving and storing a concurrently received data bit of said digital data stream in said most recently received data bits and discarding an oldest bit thereof; receiving a blanker signal having a first state designating that the concurrently received bit of said digital data stream is valid and a second state designating that the concurrently received bit of said digital data stream is invalid; storing a blanker bit corresponding to each stored bit of said digital data stream, each blanker bit designating a valid or invalid state of the corresponding bit of said digital data stream; for each concurrently received bit, serially comparing the valid stored data stream bits, beginning with an oldest bit thereof, with serial bits of the representative sample of said unique digital word, beginning with a first bit thereof, until the concurrently received bit of said most recently received bits has been compared to a last bit of said unique digital word, said comparisons occurring during a bit period of said digital data stream; counting a number of noncomparisons resulting from the step of serially comparing said stored bits of said digital data stream and the bits of said unique digital word; counting a number of blanker bits which correspond to said stored digital data stream bits and indicate invalid states; and generating an output signal to indicate detection of said unique word in the digital data stream when the number count of noncomparisons is less than a preset threshold number and the number of blanker bits does not exceed a preset limit.

Claim 12

A method for detecting a unique digital word in a digital data stream, comprising the steps of: storing a representative sample of said unique digital word; storing a preset number of the most recently received bits of said digital data stream; receiving and storing a concurrently received data bit of said digital data stream in said most recently received data bits and discarding an oldest bit thereof; receiving a blanker signal having a first state designating that the concurrently received bit of said digital data stream is valid and a second state designating that the concurrently received bit of said digital data stream is invalid; storing a blanker bit corresponding to each stored bit of said digital data stream, each blanker bit designating a valid or invalid state of the corresponding bit of said digital data stream; for each concurrently received bit, serially comparing the valid stored data stream bits, beginning with an oldest bit thereof, with serial bits of the representative sample of said unique digital word, beginning with a first bit thereof, until the concurrently received bit of said most recently received bits has been compared to a last bit of said unique digital word, said comparisons occurring during a bit period of said digital data stream; counting a number of noncomparisons resulting from the step of serially comparing said stored bits of said digital data stream and the bits of said unique digital word; counting a number of blanker bits which correspond to said stored digital data stream bits and indicate invalid states; and generating an output signal to indicate detection of said unique word in the digital data stream when the number count of noncomparisons is less than a preset threshold number and the number of blanker bits does not exceed a preset limit.

Claim 14

A method for detecting a unique digital word in a digital data stream, comprising the steps of: storing a representative sample of said unique digital word in a first memory location; storing a threshold number; presetting a unique word counter and an inverse unique word counter to said threshold number at the beginning of a bit period of said digital data stream; storing a blanker limit number; presetting a blanker counter to said limit number at the start of said bit period; storing a number of the most recently received bits of said digital data stream in a second memory location, the number of said most recently received bits equal to the number of bits in the representative sample of said unique digital word, wherein each newly received bit of said digital data stream is stored and the oldest stored bit of said digital data stream is deleted from storage; receiving a blanker signal which has a first state designating that the concurrently received bit of said digital data stream is valid and a second state designating that the concurrently received bit of said digital data stream is invalid; storing a blanker bit corresponding to each stored bit of said digital data stream in a third memory location, each said blanker bit designating a valid or invalid state of the corresponding bit of said digital data stream; sequentially generating memory addresses for said first, second and third memory locations to read out corresponding bits of said unique digital word, said data stream and said blanker signal, all of said memory addresses generated during each bit period of said digital data stream; storing the bits read out of said memories in a first latch; comparing the unique word bit with the data stream bit in said latch; comparing an inverse of the unique word bit in said latch with the data stream bit in said latch; in response to the step of comparing the unique word bit with the data stream bit, incrementing said unique word counter for each noncomparison for each said valid state data stream bit; in response to the step of comparing the inverse of the unique word bit in said latch with the data stream bit in said latch, incrementing said inverse unique word counter for each noncomparison for each said valid state data stream bit; incrementing said blanker counter for each invalid state blanker bit received by said latch; and setting a second latch to indicate detection of said unique digital word when said unique word counter does not reach a terminal count and said blanker counter does not reach a terminal count or to indicate detection of said inverse unique digital word when said inverse unique digital word counter does not reach a terminal count and said blanker counter does not reach a terminal count.

Claim 15

A method for detecting a unique digital word in a digital data stream, comprising the steps of: storing a representative sample of said unique digital word in a first memory location; storing a threshold number; presetting a unique word counter and an inverse unique word counter to said threshold number at the beginning of a bit period of said digital data stream; storing a blanker limit number; presetting a blanker counter to said limit number at the start of said bit period; storing a number of the most recently received bits of said digital data stream in a second memory location, the number of said most recently received bits equal to the number of bits in the representative sample of said unique digital word, wherein each newly received bit of said digital data stream is stored and the oldest stored bit of said digital data stream is deleted from storage; receiving a blanker signal which has a first state designating that the concurrently received bit of said digital data stream is valid and a second state designating that the concurrently received bit of said digital data stream is invalid; storing a blanker bit corresponding to each stored bit of said digital data stream in a third memory location, each said blanker bit designating a valid or invalid state of the corresponding bit of said digital data stream; sequentially generating memory addresses for said first, second and third memory locations to read out corresponding bits of said unique digital word, said data stream and said blanker signal, all of said memory addresses generated during each bit period of said digital data stream; storing the bits read out of said memories in a first latch; comparing the unique word bit with the data stream bit in said latch; comparing an inverse of the unique word bit in said latch with the data stream bit in said latch; in response to the step of comparing the unique word bit with the data stream bit, incrementing said unique word counter for each noncomparison for each said valid state data stream bit; in response to the step of comparing the inverse of the unique word bit in said latch with the data stream bit in said latch, incrementing said inverse unique word counter for each noncomparison for each said valid state data stream bit; incrementing said blanker counter for each invalid state blanker bit received by said latch; and setting a second latch to indicate detection of said unique digital word when said unique word counter does not reach a terminal count and said blanker counter does not reach a terminal count or to indicate detection of said inverse unique digital word when said inverse unique digital word counter does not reach a terminal count and said blanker counter does not reach a terminal count.