Telegraphy – Systems – Line-clearing and circuit maintenance
Patent
1976-01-26
1977-06-14
Safourek, Benedict V.
Telegraphy
Systems
Line-clearing and circuit maintenance
328155, 325322, H04L 700
Patent
active
040299007
ABSTRACT:
A data signal stream includes, in a noisy signal channel, periodic word synchronization characters, and each such stream is preceded by a burst of predetermined bit rate information. An approximate bit rate timing signal is derived from the data stream and utilized for producing an initialization pulse when the predetermined bit rate information is detected. In addition, the approximate bit rate timing signal drives a digital phase-locked loop which is preset by the initialization pulse to a digital circuit state defining operation at the nominal frequency of the approximate bit rate timing signal. A stable bit clock signal provided by the phase-locked loop controls the operation of further circuits which are responsive to the baseband data stream for providing an indicator pulse each time that a synchronizing character appears in the data stream. The bit rate clock and the character indicator pulses are employed to operate a timing chain that yields word synchronization pulses in synchronism with the indicator pulses and having an extraordinarily low false-pulse rate as well as evidencing a flywheel effect to maintain word synchronization in the event that a small number of character indicating pulses are missed. If more such pulses are missed, the timing chain is resynchronized.
REFERENCES:
patent: 3209265 (1965-09-01), Baker et al.
patent: 3228688 (1967-06-01), Brooks
patent: 3286176 (1966-11-01), Birnboim
patent: 3286188 (1966-11-01), Castellano, Jr.
patent: 3329895 (1967-07-01), Lenz
patent: 3351868 (1967-11-01), Farrow
patent: 3626311 (1971-12-01), Kraybill
patent: 3629736 (1971-12-01), Hirsch et al.
patent: 3688202 (1972-08-01), Naubereit et al.
patent: 3764902 (1973-10-01), Rodine
patent: 3806664 (1974-04-01), Bowen et al.
patent: 3820022 (1974-06-01), Watt
patent: 3889186 (1975-06-01), Larson
patent: 3898390 (1975-08-01), Wells et al.
patent: 3903482 (1975-09-01), Pausini et al.
patent: 3920900 (1975-11-01), Fineman
patent: 3949296 (1976-04-01), McClaskey et al.
patent: 3983498 (1976-09-01), Malek
High Capacity Mobile Tel System Rept., (filed in FCC Docket 18262), Dec. 1971, pp. 3-28.
Pulse, Digital and Switching Waveforms; J. Millman and H. T. Taub, 1965, pp. 726-728.
Richards, R. K., Electronic Digital Systems, 1966, pp. 424-429.
Bennett, W. R., & Davey, J. R., "Data Transmission", 1963, pp. 260-266.
Bell Telephone Laboratories Incorporated
Phelan Charles Scott
Safourek Benedict V.
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