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US 5,345,504 AGranted
Differential compensation control for off-premises CATV system
AssigneeScientific-Atlanta, Inc.
InventorLamar E. West, Jr.
Life of this patent
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AssigneeScientific-Atlanta, Inc.
InventorLamar E. West, Jr.
Estimating the term…
A off-premises CATV system includes a compensation control including a picture carrier controlled automatic gain control and an automatic slope control. A broadband television signal output from a variable gain device is distributed by a radio frequency signal splitter to a number of subscribers interdiction. The variable gain device and a variable frequency dependent device are connected in series for automatic gain control and automatic slope control, respectively. A first feedback control is used to compare a first portion of the broadband television signal to a reference power level and null the error. A second feedback control is used to compare a second portion of the broadband signal to the first portion and null the error. A second embodiment of the second feedback control differences the first and second portions of the broadband television signal. The first predetermined portion is a band of frequencies (high band) between 250 MHz. and 310 MHz. and the second predetermined portion is a band of frequencies (low band) between 54 MHz. and 150 MHz. The predetermined power level reference for automatic gain control is set to equal the attenuation between the off-premises equipment and the subscriber premises plus the desired level at the subscriber premises. The power level of a jamming signal for denying access to unauthorized television programs is set to fall within a predetermined range of power levels related to the predetermined power level reference.
An automatic slope control apparatus for use in an interdiction cable television system which automatically corrects amplitude distortions as a function of frequency of a broadband television signal transmitted to a subscriber through a cable, the slope control apparatus comprising:
An automatic compensation apparatus for use in an interdiction cable television system which automatically corrects the amplitude distortions as a function of frequency and the power level of a broadband television signal transmitted to a subscriber through a cable, the automatic compensation apparatus comprising:
Dependencies are inferred from the claim text.