Automatic canceller

Claim 2

In a processor for eliminating undesired signals from among a plurality of desired signals, means including a first terminal for receiving all said signals, means including an adder and a first circuit for transmitting all said signals from said first terminal to said adder to produce residue signals, means including a delay line and a second circuit for transmitting all said signals from said first terminal through said delay line to produce delayed signals, correlator means coupled to receive said residue signals and said delayed signals, said correlator serving to multiply said residue signals and said delayed signals and to integrate the product to provide a control signal, mixer means receiving said control signal and said delayed signals and generating a correcting signal with phase and amplitude adjusted to cancel undesired signals, and means for transmitting said correcting signal to said adder to cancel said undesired signals, said adder thereby providing improved residue signals substantially free of undesired signals.

Claim 3

In a processor for eliminating undesired signals from among desired signals where said desired and undesired signals respectively represent radar reflections from desired and undesired targets, a canceller including first and second input terminals, means for receiving the desired and undesired signals aNd supplying them to said first terminal of said canceller, a correlator, said canceller supplying residue signals to said correlator, means for receiving said desired and undesired signals and providing a time delay to produce delayed signals, a mixer, means for supplying said delayed signals to said mixer and to said correlator, said correlator multiplying the residue signals from said canceller by the delayed signals and integrating the product to provide a control signal, means for supplying said control signal to said mixer, said mixer mixing said control signal and said delayed signals to provide a correcting signal of the proper amplitude and phase to cancel said undesired signals, and means coupling said correcting signal to said second terminal of said canceller to provide for the elimination of said undesired signals.

Claim 4

In a processor for eliminating undesired signals from among desired signals where said desired and undesired signals respectively represent radar reflections from desired and undesired targets, a canceller including first and second input terminals, means for receiving the desired and undesired signals aNd supplying them to said first terminal of said canceller, a correlator, said canceller supplying residue signals to said correlator, means for receiving said desired and undesired signals and providing a time delay to produce delayed signals, a mixer, means for supplying said delayed signals to said mixer and to said correlator, said correlator multiplying the residue signals from said canceller by the delayed signals and integrating the product to provide a control signal, means for supplying said control signal to said mixer, said mixer mixing said control signal and said delayed signals to provide a correcting signal of the proper amplitude and phase to cancel said undesired signals, and means coupling said correcting signal to said second terminal of said canceller to provide for the elimination of said undesired signals.

Claim 5

In a processor for eliminating undesired IF signals from among desired IF signals where said undesired and desired signals respectively represent reflections of evenly separated radar pulses from undesired and desired targets, an input terminal for receiving all of said IF signals, means coupling said IF signals from said input terminal to a canceller, a correlator, means coupling an output signal from said canceller to said correlator, delay means, means coupling said IF signals from said input terminal to said delay means, said delay means providing a time delay to produce delayed IF signals, said time delay being substantially equal to the time between said separated radar pulses, means for supplying said delayed IF signals to said correlator, said correlator including means for multiplying the output signal from said canceller by the delayed IF signals from said delay means to provide a product signal, said correlator including means for integrating the product signal to provide a control signal, a mixer, means for coupling said control signal to said mixer, means coupling said delayed IF signals to said mixer, said mixer responding to said control signal and said delayed IF signals to provide a correcting signal of the proper amplitude and phase to cancel said undesired IF signals, and means coupling said mixer to said canceller to supply said correcting signal to cancel said undesired signals.

Claim 6

In a processor for eliminating undesired IF signals from among desired IF signals where said undesired and desired signals respectively represent reflections of evenly separated radar pulses from undesired and desired targets, an input terminal for receiving all of said IF signals, means coupling said IF signals from said input terminal to a canceller, a correlator, means coupling an output signal from said canceller to said correlator, delay means, means coupling said IF signals from said input terminal to said delay means, said delay means providing a time delay to produce delayed IF signals, said time delay being substantially equal to the time between said separated radar pulses, means for supplying said delayed IF signals to said correlator, said correlator including means for multiplying the output signal from said canceller by the delayed IF signals from said delay means to provide a product signal, said correlator including means for integrating the product signal to provide a control signal, a mixer, means for coupling said control signal to said mixer, means coupling said delayed IF signals to said mixer, said mixer responding to said control signal and said delayed IF signals to provide a correcting signal of the proper amplitude and phase to cancel said undesired IF signals, and means coupling said mixer to said canceller to supply said correcting signal to cancel said undesired signals.

Claim 7

A self adapting filter for eliminating undesired signals from among desired signals comprising a first circuit including an adder and input and output terminals and means for coupling signals appearing on said input terminal through said adder to said output terminal, a second circuit including a delay line and a second output terminal and means for coupling signals appearing on said input terminal through said delay line to produce delayed signals at said second output terminal, a correlator means, including first and second input terminals coupling said first and second output terminals to respective input terminals of said correlator, said correlator generating a control signal in response to signals appearing on its input terminals, a mixer, means coupling said control signal to said mixer, means coupling said delayed signals from the second output terminal to said mixer, said control signal correcting the phase and amplitude of said delayed signals to provide correcting signals of a phase and amplitude to nullify undesired signals in said first circuit, and means coupling said correcting signals to said adder to cancel undesired signals appearing in said first circuit.

Claim 8

A self adapting filter for eliminating undesired signals from among desired signals comprising a first circuit including an adder and input and output terminals and means for coupling signals appearing on said input terminal through said adder to said output terminal, a second circuit including a delay line and a second output terminal and means for coupling signals appearing on said input terminal through said delay line to produce delayed signals at said second output terminal, a correlator means, including first and second input terminals coupling said first and second output terminals to respective input terminals of said correlator, said correlator generating a control signal in response to signals appearing on its input terminals, a mixer, means coupling said control signal to said mixer, means coupling said delayed signals from the second output terminal to said mixer, said control signal correcting the phase and amplitude of said delayed signals to provide correcting signals of a phase and amplitude to nullify undesired signals in said first circuit, and means coupling said correcting signals to said adder to cancel undesired signals appearing in said first circuit.

Claim 9

A self adapting filter for cancelling undesired signals and passing desired signals, said undesired signals having long-time durations representing reflections of radar pulses having a constant pulse repetition period from targets having deep range extent, said desired signals having short-time durations representing reflections of said radar pulses having a constant pulse repetition period from targets having shallow range extent, said filter comprising a first circuit including an adder an input and output terminals and means for coupling signals appeaRing on said input terminal through said adder to said output terminal, a second circuit including a delay line and a second output terminal and means for coupling signals appearing on said input terminal through said delay line to produce delayed signals at said second output terminal, a correlator including first and second input terminals, means coupling said first and second output terminals to respective input terminals of said correlator, said correlator generating a control signal in response to like signals appearing on both said input terminals, a mixer, means coupling said control signal and said delayed signals from the second output terminal to said mixer, said control signal correcting the phase and amplitude of said delayed signals to provide correcting signals of a phase and amplitude corresponding to undesired signals in said first circuit, and means coupling said correcting signals to said adder to cancel undesired signals appearing in said first circuit.

Claim 10

A self adapting filter for cancelling undesired signals and passing desired signals, said undesired signals having long-time durations representing reflections of radar pulses having a constant pulse repetition period from targets having deep range extent, said desired signals having short-time durations representing reflections of said radar pulses having a constant pulse repetition period from targets having shallow range extent, said filter comprising a first circuit including an adder an input and output terminals and means for coupling signals appeaRing on said input terminal through said adder to said output terminal, a second circuit including a delay line and a second output terminal and means for coupling signals appearing on said input terminal through said delay line to produce delayed signals at said second output terminal, a correlator including first and second input terminals, means coupling said first and second output terminals to respective input terminals of said correlator, said correlator generating a control signal in response to like signals appearing on both said input terminals, a mixer, means coupling said control signal and said delayed signals from the second output terminal to said mixer, said control signal correcting the phase and amplitude of said delayed signals to provide correcting signals of a phase and amplitude corresponding to undesired signals in said first circuit, and means coupling said correcting signals to said adder to cancel undesired signals appearing in said first circuit.

Claim 11

A processor for cancelling long-time duration signals representing radar reflections of undesired targets having large range extent from among short-time duration signals representing radar reflections of targets having small range extent comprising, an input terminal for receiving said signals, an adder for accepting all the signals appearing on said input terminal, a correlator, means for supplying the output of said adder to said correlator, delay means having a time delay period substantially equal to the time between pulses of a transmitted radar for accepting all the signals appearing on said input terminal and providing delayed signals having a delay substantially equal to one radar pulse repetition period, a mixer, means for supplying said delayed signals to said mixer and to said correlator, said correlator generating a control signal in response to like signals from said adder and from said delay means, means for supplying said control signal to said mixer, said mixer providing a correcting signal of the proper amplitude and phase to cancel said long-time duration signals, and means for supplying said correcting signal to the adder to cancel said undesired long-time duration signals.

Claim 12

A processor for cancelling long-time duration signals representing radar reflections of undesired targets having large range extent from among short-time duration signals representing radar reflections of targets having small range extent comprising, an input terminal for receiving said signals, an adder for accepting all the signals appearing on said input terminal, a correlator, means for supplying the output of said adder to said correlator, delay means having a time delay period substantially equal to the time between pulses of a transmitted radar for accepting all the signals appearing on said input terminal and providing delayed signals having a delay substantially equal to one radar pulse repetition period, a mixer, means for supplying said delayed signals to said mixer and to said correlator, said correlator generating a control signal in response to like signals from said adder and from said delay means, means for supplying said control signal to said mixer, said mixer providing a correcting signal of the proper amplitude and phase to cancel said long-time duration signals, and means for supplying said correcting signal to the adder to cancel said undesired long-time duration signals.

Claim 13

A processor for cancelling long-time signals representing radar reflections of undesired targets having great range extent from among short-time signals representing radar reflections of targets having small range extent comprising, an adder for accepting all the signals, a correlator, means for applying the output of said adder to said correlator, delay means for accepting all the signals and providing a delay equal to one radar pulse repetition period to all the signals, a mixer, means for supplying said delayed signals to said mixer and to said correlator, said correlator generating a control signal in response to long-time signals supplied simultaneously from said adder and from said delay means, means for supplying said control signal to said mixer, said mixer providing a correcting signal of the proper amplitude and phase to cancel said long-time signals, and means for supplying said correcting signal to the adder to cancel said undesired long-time signals.

Claim 14

A processor for cancelling long-time signals representing radar reflections of undesired targets having great range extent from among short-time signals representing radar reflections of targets having small range extent comprising, an adder for accepting all the signals, a correlator, means for applying the output of said adder to said correlator, delay means for accepting all the signals and providing a delay equal to one radar pulse repetition period to all the signals, a mixer, means for supplying said delayed signals to said mixer and to said correlator, said correlator generating a control signal in response to long-time signals supplied simultaneously from said adder and from said delay means, means for supplying said control signal to said mixer, said mixer providing a correcting signal of the proper amplitude and phase to cancel said long-time signals, and means for supplying said correcting signal to the adder to cancel said undesired long-time signals.

Claim 15

A processor for cancelling long-time signals representing reflections of radar pulses having a constant pulse repetition period from targets having deep range extent and for preserving short-time signals representing reflections of said radar pulses having a constant pulse repetition rate from targets having shallow range extent comprising, a correlator, an adder for accepting all the signals, means for supplying the output of said adder to said correlator, delay means for accepting all the signals and providing a delay substantially equal to one radar pulse repetition period to all the signals, a mixer, means for supplying delayed signals from said delay means to said mixer and to said correlator, said correlator generating a control signal in response to signals of the same form from said adder and from said delay means, means for supplying said Control signal to said mixer, said mixer responding to said delayed signals and to said control signal to provide a correcting signal of the proper amplitude and phase to cancel said long-time signals, and means for supplying said correcting signal to the adder to cancel said undesired long-time signals.

Claim 16

A processor for cancelling long-time signals representing reflections of radar pulses having a constant pulse repetition period from targets having deep range extent and for preserving short-time signals representing reflections of said radar pulses having a constant pulse repetition rate from targets having shallow range extent comprising, a correlator, an adder for accepting all the signals, means for supplying the output of said adder to said correlator, delay means for accepting all the signals and providing a delay substantially equal to one radar pulse repetition period to all the signals, a mixer, means for supplying delayed signals from said delay means to said mixer and to said correlator, said correlator generating a control signal in response to signals of the same form from said adder and from said delay means, means for supplying said Control signal to said mixer, said mixer responding to said delayed signals and to said control signal to provide a correcting signal of the proper amplitude and phase to cancel said long-time signals, and means for supplying said correcting signal to the adder to cancel said undesired long-time signals.

Claim 17

A processor for cancelling long-time signals representing reflections made by equally spaced radar pulses from targets having great range extent and for preserving short-time signals representing reflections made by said equally spaced radar pulses from targets having small range extent comprising, an adder for accepting all the signals, a correlator, means for supplying the output of said adder to said correlator, delay means for accepting all the signals and providing delayed signals having a delay equal to the time between equally spaced radar pulses, a mixer, means for supplying said delayed signals to said mixer and to said correlator, said correlator generating a control signal in response to similar signals provided simultaneously from said adder and from said delay means, means for supplying said control signal to said mixer, said mixer providing a correcting signal of the proper amplitude and phase to cancel said longtime signals, and means for supplying said correcting signal to the adder to cancel said undesired long-time signals.

Claim 18

A processor for cancelling long-time signals representing reflections made by equally spaced radar pulses from targets having great range extent and for preserving short-time signals representing reflections made by said equally spaced radar pulses from targets having small range extent comprising, an adder for accepting all the signals, a correlator, means for supplying the output of said adder to said correlator, delay means for accepting all the signals and providing delayed signals having a delay equal to the time between equally spaced radar pulses, a mixer, means for supplying said delayed signals to said mixer and to said correlator, said correlator generating a control signal in response to similar signals provided simultaneously from said adder and from said delay means, means for supplying said control signal to said mixer, said mixer providing a correcting signal of the proper amplitude and phase to cancel said longtime signals, and means for supplying said correcting signal to the adder to cancel said undesired long-time signals.

Claim 19

In a pulse echo receiving system, means to receive desired echoes of radiated periodic pulses from remote objects having short range depth such that the echo pulses produced thereby have duration about equal to the radiated pulse, while eliminating undesired echoes from reflectors of greater range depth which produce echoes of the character of ground clutter, and sea, weather, and chaff returns, etc. said means comprising an input circuit in which both said desired and undesired echoes are received, a correlator, means to transmit the received echoes from said circuit through two channels to said correlator, one of said channels including means to delay echoes transmitted through it by the period between successive radiated pulses, said correlator comprising means to multiply the output of said two channels and to integrate the product, said correlator having a response time greater than the duration of desired echo pulses to be received, whereby a correction wave is produced corresponding to said undesired echoes, but free of desired echoes, and means to apply said correction wave to the other of said channels to reduce undesired long range echoes therein while not reducing desired short range depth echoes.

Claim 20

In a pulse echo receiving system, means to receive desired echoes of radiated periodic pulses from remote objects having short range depth such that the echo pulses produced thereby have duration about equal to the radiated pulse, while eliminating undesired echoes from reflectors of greater range depth which produce echoes of the character of ground clutter, and sea, weather, and chaff returns, etc. said means comprising an input circuit in which both said desired and undesired echoes are received, a correlator, means to transmit the received echoes from said circuit through two channels to said correlator, one of said channels including means to delay echoes transmitted through it by the period between successive radiated pulses, said correlator comprising means to multiply the output of said two channels and to integrate the product, said correlator having a response time greater than the duration of desired echo pulses to be received, whereby a correction wave is produced corresponding to said undesired echoes, but free of desired echoes, and means to apply said correction wave to the other of said channels to reduce undesired long range echoes therein while not reducing desired short range depth echoes.

Claim 21

In a pulse echo receiving system, means to receive desired echoes of radiated periodic pulses from remote objects having short range depth such that the echo pulses produced thereby have duration about equal to the radiated pulse, while eliminating undesired echoes from reflectors of greater range depth which produce echoes of long range depths of the character of ground clutter, and sea, weather, and chaff returns, etc. said means comprising an input circuit in which both said desired and undesired echoes are received, a correlator, means to transmit the received echoes from said circuit through two channels to said correlator, one of said channels including means to delay echoes transmitted through it by the period between successive radiated pulses, said correlator comprising means to multiply the output of said two channels and to integrate the product, said correlator having a response time greater than the duration of desired echo pulses to be received, whereby a correction wave is produced corresponding to said undesired echoes, but free of desired echoes, and means for combining said correction wave with the delayed output of said one channel and applying the result to the other of said channels to reduce undesired long range depth echoes therein while said other channel continues to transmit desired short range depth echoes, and output load means responsive to said desired short range depth echoes.

Claim 22

In a pulse echo receiving system, means to receive desired echoes of radiated periodic pulses from remote objects having short range depth such that the echo pulses produced thereby have duration about equal to the radiated pulse, while eliminating undesired echoes from reflectors of greater range depth which produce echoes of long range depths of the character of ground clutter, and sea, weather, and chaff returns, etc. said means comprising an input circuit in which both said desired and undesired echoes are received, a correlator, means to transmit the received echoes from said circuit through two channels to said correlator, one of said channels including means to delay echoes transmitted through it by the period between successive radiated pulses, said correlator comprising means to multiply the output of said two channels and to integrate the product, said correlator having a response time greater than the duration of desired echo pulses to be received, whereby a correction wave is produced corresponding to said undesired echoes, but free of desired echoes, and means for combining said correction wave with the delayed output of said one channel and applying the result to the other of said channels to reduce undesired long range depth echoes therein while said other channel continues to transmit desired short range depth echoes, and output load means responsive to said desired short range depth echoes.