Digital data scrambler and descrambler
AssigneeInternational Standard Electric Corporation
InventorMichael David Patten
Life of this patent
Estimating the term…
Abstract
A digital data scrambler and descrambler for m parallel synchronized digital data streams, where m is an integer greater than one, is disclosed. The scrambler and descrambler each include m linear sequential filters, each of the m filters being associated with a different one of the m data streams. Each of the scrambler filters include a feedback path and tapping connections to the feedback path and each of the descrambler filters include a feedforward path and tapping connections to the feedforward path. The nature and location of the tapping connections of both the scrambler and descrambler filters are determined in accordance with a polynomial expression which is the same for a matched scrambler and descrambler.
Claims15
In a digital data transmission sytem, the combination of a digital data scrambler comprising:
- m inputs each associated with a different one of m input synchronized binary coded data streams, where m is an integer greater than one,
- first m linear sequential filters each coupled to a different one of said m inputs,
- a first given number of feedback paths coupled to each of said first m filters from the output to the input of each of said first m filters, and
- a first plurality of tap connections coupled between each of said first m filters an asociated ones of said feedback paths,
- the nature and disposition of said first tap connections being determined in accordance with a given polynomial having only binary coefficients, said given polynomial being used for each of said first m filters with the sequence of said first tap connections of each of said first m filters being shifted cyclically, with respect to the input of said first m filters, from one of said first m filters to the next of said first m filters;
- and
- a digital data descrambler coupled to said scrambler to recover said m input data streams comprising:
- second m linear sequential filters each coupled to an output of different ones of said first m filters,
- a second given number of feedforward paths coupled to each of said second m filters from the input to the output of each of said second m filters, said second given number being equal to said first given number, and
- a second plurality of tap connections coupled between each of said second m filters and associated ones of said feedforward paths, said second plurality being equal in number to said first plurality,
- the nature and disposition of said second tap connections being determined in accordance with said given polynomial, said given polynomial being used for each of said second m filters with the sequence of said second tap connections of each of said second m filters being shifted cyclically the same as the sequence of said first tap connections.
A digital data scrambler for a digital data transmission system comprising:
- m inputs each associated with a different one of m input synchronized binary coded data stream, where m is an integer greater than one;
- m linear sequential filters each coupled to a different one of said m inputs;
- a given number of feedback paths coupled to each of said m filters from the output to the input of each of said m filters;
- and
- a plurality of tap connections coupled between each of said m filters and associated ones of said feedback paths;
- the nature and disposition of said tap connections being determined in accordance with a given polynomial having only binary coefficients, said given polynomial being used for each of said m filters to determine the cyclic shifting of the sequence of said tap connections of each of said m filters with respect to the input of said m filters, from one of said m filters to the next of said m filters.
A descrambler for a digital data transmission system to recover input digital data stream scrambled at a transmitter from said scrambled digital data streams received at a receiver comprising:
- m inputs each associated with a different one of m scrambled synchronized binary coded data streams, where m is an integer greater than one;
- m linear sequential filters each coupled to a different one of said m inputs;
- a given number of feedforward paths coupled to each of said m filters from the input to the output of each of said m filters;
- and
- a plurality of tap connections coupled between each of said m filters and associated ones of said feedforward paths;
- the nature and disposition of said tap connections being determined in accordance with a given polynomial having only binary coefficients, said given polynomial being used for each of said m filters with the sequence of said tap connections being shifted cyclically, with respect to the input of said m filters, from one of said m filters to the next of said m filters.
Dependencies are inferred from the claim text.