Television – Special applications – Manufacturing
Patent
1996-08-15
2000-07-25
Faile, Andrew I.
Television
Special applications
Manufacturing
348 12, 348 13, 348614, 455 31, H04N 710, H04N 714, H04N 521, H04N 5213
Patent
active
060942118
ABSTRACT:
This invention permits the upstream transmission of short packets of information in a cable TV system, and blocking upstream noise at all other times, and does so without interfering with image quality of normal TV viewing. A remotely operable ingress noise blocking filter is placed at the terminating junction between a subscriber's coaxial drop cable and a corresponding feeder tap in a cable TV system. The ingress noise blocking filter contains a high pass filter to pass the normal TV band. This high pass filter is bypassed by a section containing low pass filters and a switch operated when receiving a control signal from a cable modem during those short durations the cable modem is authorized to transmit an upstream signal. Low pass filters isolate the switching elements so that switching transients cannot occur in the downstream TV band. The level of the amplitude of the downstream signal is unaffected whether the switching elements are open or closed. Further, the switching arrangement provides a relatively constant impedance, both when the switching element is on and off to provide a high return loss and avoid signal reflections and maintain signal quality. In a diagnostic mode, the location of each noise source is determined by correlating the energy measured at each a set of frequencies across the band at the headend during those periods when the cable modem is allowed to transmit versus the energy received during those periods when the same cable modem is not authorized to transmit.
REFERENCES:
patent: 3806813 (1974-04-01), Eller
patent: 3924187 (1975-12-01), Dormans
patent: 4494138 (1985-01-01), Shimp
patent: 4520508 (1985-05-01), Reichert, Jr.
patent: 4530008 (1985-07-01), McVoy
patent: 4633462 (1986-12-01), Stifle et al.
patent: 4701726 (1987-10-01), Holdsworth
patent: 4928272 (1990-05-01), Ohue
patent: 4982440 (1991-01-01), Dufresne et al.
patent: 5126840 (1992-06-01), Dufresne et al.
patent: 5233418 (1993-08-01), Gumm et al.
patent: 5317392 (1994-05-01), Ishibashi et al.
patent: 5408259 (1995-04-01), Warwick
patent: 5499047 (1996-03-01), Terry et al.
patent: 5561404 (1996-10-01), Ross
patent: 5585842 (1996-12-01), Chappel et al.
Roger Brown, Poised for Competition in California, CED Magazine, p. 5, Aug. 1995.
Thomas Staniec, Making It Work: Return Systems Successful Interactivity 101, CED Magazine, pp. 66-72, Aug. 1995.
Leslie Ellis, Pacbell Defends Hybrid Fiber/Coax: `Right Technology at Right Price`, Broadband Week, pp. 33-35, Jul. 3, 1995.
Baran Paul
Bunya George K.
Heinzmann F. Jud
Hollimon Marshall H.
Com21, Inc.
Faile Andrew I.
Jones Allston L.
Srivastava Vivek
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