摘要 |
A method and apparatus for determining the state, at any time in the pas t, relative to a present state, of a linear feedback shift register comprises determining a an inverse transition matrix which, if multiplied by the current state in modul o- 2 arithmetic, yields the state one step into the past; and multiplying in modulo-2 arithmetic the present state of the linear feedback shift register by the inverse transitio n matrix N times to obtain the state N steps into the past.
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