Scrambler with self-calibration
AssigneeScientific-Atlanta, Inc.
InventorsWilliam T. Murphy, James Farmer, Lamar West, Jr.
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Abstract
The invention is directed to an improved scrambler capable of self-calibrating output signals. In one embodiment, the scrambler provides an encoded signal along separate signal pulses. A portion of one signal is made to correspond to a portion of another signal to thereby self-calibrate the signals. Also, portions of the incoming video signal are forced to correspond with internally generated voltage level signals.
Claims15
A scrambler for use in a video system comprising:
- means for simultaneously generating a plurality of video signals each having a video portion and a synchronization portion;
- comparing means for comparing corresponding portions of at least first and second of said plurality of video signals to each other;
- and
- self-calibrating means responsive to said comparing means for self-calibrating an output of the scrambler based on a predetermined operation involving the synchronization portions of said first and second video signals.
A self-calibrating scrambler for use in a video system, wherein the video system comprises video signals having at least a video signal portion and a synchronization signals portion, the scrambler comprising:
- means for simultaneously generating an inverted signal having at least a portion of the video signal inverted and a non-inverted video signal;
- comparing means for comparing corresponding portions of the inverted and non-inverted video signal to each other;
- and
- modifying means responsive to the comparing means for modifying one of the inverted or non-inverted video signals to thereby self-calibrate an output of the scrambler.
A self-calibrating scrambler for use in a video system wherein the scrambler is capable of producing and selectively outputting inverted and non-inverted video signals, said signals including synchronization signals comprising a low synchronization pulse and a high synchronization pulse, said scrambler comprising:
- means for sampling and holding signals corresponding to the low synchronization pulses of the inverted and non-inverted video signals;
- first comparator means for comparing said low synchronization pulses;
- means responsive to said first comparator means for adjusting a DC level of one of the low synchronization pulses;
- means for sampling and holding signals corresponding to the high synchronization pulses of the inverted and non-inverted video signals;
- second comparator means for comparing said high synchronization pulses;
- and
- means responsive to said second comparator means for adjusting the gain of one of said video signals.
An encoder capable of selectively outputting an encoded or non-encoded signal from one of the plurality of signal paths, comprising:
- means for providing an encoded signal along a first of said plurality of signal paths;
- means for providing a non-encoded signal along a second of said plurality of signal paths simultaneously with said encoded signal;
- comparing means for comparing corresponding portions of said encoded and non-encoded signals to each other;
- and
- means responsive to said comparing means for making at least a portion of one of said non-encoded signals correspond to a respective portion of the other of said non-encoded or encoded signals.
A scrambler for selectively outputting one of a plurality of signals, comprising:
- means for simultaneously generating a plurality of signals comprising at least a first signal having a first characteristic and a second signal having a second characteristic;
- comparing means for comparing corresponding portions of said first and second signals to each other;
- and
- modifying means responsive to said comparing means for modifying one of the first or second signals to thereby self-calibrate an output of the scrambler.
A scrambler for selectively outputting one of a plurality signals, comprising:
- means for generating a plurality of signals comprising at least a first signal having a first characteristic and a second signal having a second characteristic;
- and
- self-calibrating means for self-calibrating said first and second signals, said self-calibrating means comprising a gated integrator.
Dependencies are inferred from the claim text.