Frame synchronization in a performance monitoring and test system
First Claim
1. A method of frame synchronization, comprising the steps of:
- storing a first n bits of a digital signal into a current frame memory;
shifting n-m of the first n bits into a previous frame memory;
storing a second n bits of the digital signal into the current frame memory;
comparing at least one bit from the current memory with at least one bit from the previous memory;
incrementing a state counter when a condition of the comparison is successful; and
comparing the state counter to a threshold such that the result is indicative of frame synchronization.
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Accused Products
Abstract
A DS3 level access, monitor and test system for a telephone network. The system provides selective, and hitless, bit overwrite in any of the embedded DS1, DS0 and subrate channels in a DS3 signal. Multiple DS0 and subrate channels can be tested via the asynchronous time slot interchange in conjunction with the recombiner of the present invention. The present invention further includes a lookahead reframer for framing to the DS3 signal. The present invention also includes a facilities data link (FDL) handler for capturing the FDL channel data in every DS1 channel in a DS3 signal. A high speed bit-for-bit compare is interfaced to a protect path to provide 1:1 fault protection in the system of the present invention. Full time performance monitoring on DS1 and DS3 signals is performed by a shared resource. The system of the present invention provides an integrated approach to synchronization measurement and relative synchronization.
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Citations
15 Claims
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1. A method of frame synchronization, comprising the steps of:
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storing a first n bits of a digital signal into a current frame memory; shifting n-m of the first n bits into a previous frame memory; storing a second n bits of the digital signal into the current frame memory; comparing at least one bit from the current memory with at least one bit from the previous memory; incrementing a state counter when a condition of the comparison is successful; and comparing the state counter to a threshold such that the result is indicative of frame synchronization. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A frame synchronization circuit, comprising:
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a shift register comprising a current frame memory of n bits and a previous frame memory of at least n-m bits, wherein n consecutive bits of a signal containing framing bits are stored in the current frame memory and n-m bits of the current frame memory are selectively shifted into the previous frame memory, and wherein at least one potential framing bit selected from each of the current and previous frame memories is selectively shifted into a specified bit position of each of the respective frame memories; and a first comparator for comparing at least one bit from the current memory with at least one bit from the previous memory. - View Dependent Claims (12, 13, 14, 15)
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Specification