System for echo cancellation comprising an improved ghost cancellation reference signal
AssigneeNorth American Philips Corporation
InventorDavid Koo
Life of this patent
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Abstract
A television receiver comprising a system for improved echo cancellation. The system features a superior ghost cancellation reference signal which exhibits improved performance in noisy environments and which exhibits the flat and wide bandwidth necessary for effective channel characterization whiel exhibiting a higher and more evenly distributed amplitude versus time characteristic than that provided by known, non-cyclic ghost cancellation signals.
Claims11
A television receiver for receiving a television signal which has been provided over a transmission path and subjected to path induced distortion, said television signal comprising a reference signal, said television receiver comprising:
- a) means for receiving said television signal and for separating therefrom said reference signal as distorted by said transmission path;
- and
- b) means for substantially eliminating said path induced distortion from said received television signal;
- wherein said reference signal is non-cyclic, has a substantially flat frequency response within the bandwidth of said transmission path, and a plurality of substantially uniform amplitude peaks over a time interval.
A method of encoding a signal for delivery to a path adding distortions to said signal, said method comprising the steps of:
- generating said signal;
- generating a reference signal capable of therefrom deriving coefficients to be used with at least one decoding filter for removing said distortions from said signal;
- and
- inserting said reference signal into said signal;
- wherein said reference signal is non-cyclic, has a substantially flat frequency response within the bandwidth of said transmission path, and a plurality of substantially uniform amplitude peaks over a time interval.
A method of encoding a signal for delivery to a path adding distortions to said signal, said method comprising the steps of:
- generating said signal;
- generating a reference signal capable of therefrom deriving coefficients to be used with at least one decoding filter for removing said distortions from said signal;
- and
- inserting said reference signal into said signal;
- wherein said reference signal is a ghost cancellation reference signal described by the equation:
- ##EQU5## where .alpha.,A, C.sub.n, b and .OMEGA. are real numbers;
- where
- N is an integer;
- and
- where
- W(w) is a windowed window function.
A method of encoding a signal for delivery to a path adding distortions to said signal, said method comprising the steps of:
- generating said signal;
- generating a reference signal capable of therefrom deriving coefficients to be used with at least one decoding filter for removing said distortions from said signal;
- and
- inserting said reference signal into said signal;
- wherein said reference signal is a ghost cancellation reference signal described by the equation:
- ##EQU6## where A, b and .OMEGA. are real numbers;
- and
- where
- W(.omega.) is a windowed window function.
A method of encoding a television signal for delivery over a path adding distortions to said television signal, said method comprising the steps of:
- generating a reference signal capable of therefrom deriving coefficients to be used with at least one decoding filter for removing said distortions from said signal;
- and
- inserting said reference signal into said television signal;
- wherein said reference signal is non-cyclic, has a substantially flat frequency response within the bandwidth of said transmission path, and a plurality of substantially uniform amplitude peaks over a time interval.
A method of encoding a television signal for delivery over a path adding distortions to said television signal, said method comprising the steps of:
- generating a reference signal capable of therefrom deriving coefficients to be used with at least one decoding filter for removing said distortions from said signal;
- and
- inserting said reference signal into said television signal;
- wherein said reference signal is a ghost cancellation reference signal described by the equation:
- ##EQU7## where .alpha.,A, C.sub.n, b and .OMEGA. are real numbers;
- where
- N is an integer;
- and
- where
- W(.omega.) is a windowed window function.
A method of encoding a television signal for delivery over a path adding distortions to said television signal, said method comprising the steps of:
- generating a reference signal capable of therefrom deriving coefficients to be used with at least one decoding filter for removing said distortions from said signal;
- and
- inserting said reference signal into said television signal;
- wherein said reference signal signal is a ghost cancellation reference signal described by the equation:
- ##EQU8## where .alpha.,A, C.sub.n, b and .OMEGA. are real numbers;
- where
- N is an integer;
- and
- where
- W(.omega.) is a windowed window function.
Dependencies are inferred from the claim text.