Television – Monitoring – testing – or measuring – Transmission path testing
Reexamination Certificate
2000-01-25
2004-12-21
Srivastava, Vivek (Department: 2611)
Television
Monitoring, testing, or measuring
Transmission path testing
C725S107000, C455S067150
Reexamination Certificate
active
06833859
ABSTRACT:
FIELD OF THE INVENTION
The field of the invention relates to cable television systems and more particularly to the identification to radio frequency leaks in the distribution cables of such systems.
BACKGROUND OF THE INVENTION
Community antenna television (CATV) systems are known. Such systems typically receive television signals from a variety of sources (e.g., by satellite, land lines, production studios, etc.) and distribute such signals among their subscribers within a community.
Television signals provided to the CATV system are often provided under a hodgepodge of spectrally overlapping and non-overlapping formats. Often the signals must be spectrally relocated according to a local CATV frequency plan for purposes of re-transmission.
In general, CATV systems transmit television signals in a frequency range of from 50 to 71 GHz. Often individual television signals are assigned 6 MHz slots at predetermined locations within the range and separated one-from-another by a guard band.
CATV systems distribute their signals to subscribers almost exclusively through coaxial cable systems. Where distribution distances are long, amplifiers are periodically provided to elevate signals to an acceptable level.
While the existing methods of CATV signal distribution is effective, it has the potential to disrupt other communication systems. For example, airlines typically use the same frequency range for communicating with landing towers. Where significant radio frequency (rf) leaks exist, the potential for airline disasters is significant.
Recently the Federal Communications Commission (FCC) has mandated that CATV operators test their signal distribution system for rf leaks. However, reliable equipment and techniques for accomplishing this objective, for the most part, do not exist. Accordingly, a need exists for reliable methods of detecting rf leaks in CATV systems.
SUMMARY
A method and apparatus are provided for determining a source of a leakage signal from a distribution cable of a cable television distribution system. The method includes the steps of sampling the leakage signal from the distribution cable of the cable television distribution system at each of a plurality of geographic locations within an environs of the cable, forming a leakage signal profile relating each sample with a respective location of the plurality of geographic locations; and determining a source location of the leakage signal based upon the formed profile.
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Estep Randy
Schneider Raymond J.
Comsonics, Inc.
Demicco Matthew
Srivastava Vivek
LandOfFree
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