US3920894A
Expired / Lapsed
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Pseudo-random parallel word generator
Assignee: AT&T Inc
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Filing: 1974-03-11
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Granted: 1975-11-18
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Expires: 1994-03-11
Abstract
Abstract A low speed, parallel word generator is developed from a series connected pseudo-random word generator that comprises a maximal length feedback shift register with a modulo-2 adder in the feedback path. More specifically, the n cells of said shift register are reconnected to form a parallel m-rail output version of the series connected word generator. The m-rail output has a pseudo-random binary sequence that is normally the same as the pseudo-random output sequence of the series word generator. The reconnecting circuitry includes a plurality of modulo-2 adders selectively connected between predetermined cells of the parallel word generator. Clock pulse signals are applied to each of the cells of the reconnected circuit at a rate that is normally 1/m times the rate at which the series word generator is clocked. A skip mode is periodically established, after a preselected number of input clock pulses, to cause the parallel word generator to skip a normal clock pulse period and alternatively to advance the parallel format, pseudo-random, binary sequence by a selected additional amount.
Inventors
- 👤 Dorrel Roosevelt Shirley
- 👤 Sr Gilbert Johnson Stiles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:50
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03828; H04L25/03866; H04L25/03872
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
207 words
In a digital transmission system having a series connected pseudo-random word generator comprising an n-cell feedback shift register with at least one modulo-2 adder in the feedback path thereof, said word generator serving to scramble the binary data signals of a plurality of data sources in a pseudo-random fashion; a parallel word generator characterized by means for reconnecting the n-cells of said shift register to form a parallel m-rail output version of said series connected word generator, the composite m-rail output signal that is collectively developed on the parallel output rails of the parallel word generator having a pseudo-random binary sequence that is normally the same as the pseudo-random output sequence of said series connected word generator, the reconnecting means comprising a plurality of modulo-2 adders selectively connected between predetermined cells of said parallel word generator, means for applying clock pulse signals to said parallel word generaTor at a rate that is normally 1/m times the rate at which the series word generator is clocked, and means for causing the parallel word generator to skip a normal clock pulse period after a preselected number of input clock signals thereto and alternatively to advance the periodic pseudo-random output of the parallel word generator by a given additional amount.
Claim 2
Dependent Claim
207 words
In a digital transmission system having a series connected pseudo-random word generator comprising an n-cell feedback shift register with at least one modulo-2 adder in the feedback path thereof, said word generator serving to scramble the binary data signals of a plurality of data sources in a pseudo-random fashion; a parallel word generator characterized by means for reconnecting the n-cells of said shift register to form a parallel m-rail output version of said series connected word generator, the composite m-rail output signal that is collectively developed on the parallel output rails of the parallel word generator having a pseudo-random binary sequence that is normally the same as the pseudo-random output sequence of said series connected word generator, the reconnecting means comprising a plurality of modulo-2 adders selectively connected between predetermined cells of said parallel word generator, means for applying clock pulse signals to said parallel word generaTor at a rate that is normally 1/m times the rate at which the series word generator is clocked, and means for causing the parallel word generator to skip a normal clock pulse period after a preselected number of input clock signals thereto and alternatively to advance the periodic pseudo-random output of the parallel word generator by a given additional amount.
Claim 3
Dependent Claim
44 words
In a digital transmission system as defined in claim 1 including means for modulo-2 coupling each of the m outputs of the parallel word generator and the complements thereof to said data sources to respectively scramble each of the latter in a pseudo-random fashion.
Claim 4
Dependent Claim
43 words
In a digital transmission system as defined in claim 2 wherein the periodic pseudo-random output of the parallel word generator is advanced by an additional amount equivalent to the advance produced in the series word generator by a single input clock signal thereto.
Claim 5
Dependent Claim
21 words
In a digital transmission system as defined in claim 3 wherein n and m are integers greater than one, and n>m.
Claim 6
Dependent Claim
49 words
In a digital transmission system as defined in claim 4 wherein said series connected word generator comprises a maximal length feedback shift register of seven cells; said parallel word generator comprising a three-rail output with the cells thereof connected to normally form three parallel circuits of tandem connected cells.
Claim 7
Independent Claim
188 words
A method for producing in a parallel format a pseudo-random binary signal sequence that is the same as a predetermined pseudo-random sequence selectively derived from a series connected pseudo-random word generator comprised of an n-cell feedback shift register having at least one modulo-2 adder in the feedback path, comprising the steps of reconnecting the n-cells of said shift register to form a parallel m-rail output version of said series connected word generator, the composite m-rail output signal that is collectively developed on the m parallel output rails having a pseudo-random binary sequence that is normally the same as the pseudo-random output sequence of said series connected word generator, applying clock pulse signals to each of the cells of the reconnected circuit at a rate that is normally 1/m times the rate at which the series connected word generator is clocked, and skipping a normal clock pulse period after a preselected number of input clock pulse signals and alternatively advancing the parallel format, pseudo-random, binary signal sequence by a predetermined additional amount equivalent to the advance produced in the series word generator by a single input clock signal thereto.
Claim 8
Independent Claim
188 words
A method for producing in a parallel format a pseudo-random binary signal sequence that is the same as a predetermined pseudo-random sequence selectively derived from a series connected pseudo-random word generator comprised of an n-cell feedback shift register having at least one modulo-2 adder in the feedback path, comprising the steps of reconnecting the n-cells of said shift register to form a parallel m-rail output version of said series connected word generator, the composite m-rail output signal that is collectively developed on the m parallel output rails having a pseudo-random binary sequence that is normally the same as the pseudo-random output sequence of said series connected word generator, applying clock pulse signals to each of the cells of the reconnected circuit at a rate that is normally 1/m times the rate at which the series connected word generator is clocked, and skipping a normal clock pulse period after a preselected number of input clock pulse signals and alternatively advancing the parallel format, pseudo-random, binary signal sequence by a predetermined additional amount equivalent to the advance produced in the series word generator by a single input clock signal thereto.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |