Blanking system

• US 8,150,325 B1
• Filed: 06/12/2008
• Issued: 04/03/2012
• Est. Priority Date: 06/12/2008
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Prichard, Brad A.
• Primary Examiner(s): Milord, Marceau
• Application Number:
  US12/137,834
• Time in Patent Office: 1,391 Days
• Field of Search: 455/63.1, 455/69, 455/67.11, 455/67.13, 455/67.16, 455/204, 455/223
• US Class Current: 455/63.1
• CPC Class Codes: H03G 3/348 Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

An exemplary signal interference control system is disclosed that utilizes a computer system, such as programmable logic circuits or computer controlled logic gates, to generate blanking or control signals for various types of radio frequency receiver and transmitter combinations. Control signals are generated based on signal characteristic information stored in a memory including a delay following receipt of a pre-trigger signal from a radio frequency transmitter and a pulse width of control signal(s) generated for specified receivers, frequencies or systems. In one embodiment, information can be retrieved from a memory and used to generate an interference control signal. One or more control signals can be routed to a related or associated receiver to reduce or eliminate interference effects. Data representing associated radio frequency transmitters and receivers can be determined, synchronized and stored in data structures during testing operations until the received interference signals are properly aligned, synchronized or controlled at an associated receiver. Modified control signal data such as delay and interference control signal width information can be stored in a memory and used for future control signal generation.

Claims

1. A signal processing system comprising:

a signal processor having a plurality of circuits, each circuit being adapted to generate a blanking pulse signal having a given duration a predetermined amount of time after receiving a pre-trigger signal at a first input of the last mentioned circuit from one of a plurality of EMS transmitters and each of said plurality of EMS transmitters transmits an EMS signal at the end of its predetermined amount of time;

a first signal router adapted to route pre-trigger signals from an EMS transmitter to at least one of said signal processor circuits;

a second signal router adapted to route blanking pulse signals generated by and at the output of ones of said signal processor circuits to selected ones of a plurality of EMS receivers to protect them from signal interference caused by interference reflections of said EMS signals that are received at said receivers by either rendering said EMS receivers incapable of receiving any EMS signals during the duration of each blanking pulse signal or by rendering said EMS receivers incapable of displaying any EMS signals during the duration of each blanking pulse signal; and

memory storing both the predetermined amount of time following a pre-trigger signal associated with each EMS transmitter and the duration of a blanking pulse signal to be routed to each EMS receiver, each predetermined amount of time and duration of a blanking pulse signal being retrieved from said memory following receipt of a pre-trigger signal and used to generate a blanking pulse signal.

2. The signal processing system in accordance with claim 1 wherein each of said plurality of signal processor circuits comprises a latching AND gate having two inputs, a reset input and an output, said two inputs, said reset input and said output are in a first state when said AND gate is not in use and are in a second state at different times when said gate is in use generating a blanking pulse signal.

3. The signal processing system in accordance with claim 2 wherein each pre-trigger signal from an EMS transmitter is input to a first of said two inputs of a latching AND gate and causes said first input to change from its first state to its second state, wherein after said predetermined amount of time after receipt of a pre-trigger signal said second of said two inputs is caused to change from its first state to its second state and when said two inputs are in their second state the output of said last mentioned AND gate changes from its first state to its second state and thereby commences said blanking pulse signal at said output and after a time equal to said given blanking pulse signal width said reset input changes from its first state to its second state which results in said two inputs being reset to their first state and the output is thereby caused to return to its first state and thereby end said blanking pulse signal.

4. The signal processing system in accordance with claim 3 further comprising:

first timing means timing said predetermined amount of time after receipt of said pre-trigger signal and then generating a first pulse that is applied to said second input to change it from its first state to its second state and

second timing means started after said first timing means has timed said predetermined amount of time for timing said blanking pulse signal width and then generating a second pulse that is applied to said reset input to change it from its second state to its first state to end said blanking pulse signal.

5. The signal processing system in accordance with claim 1 of further comprising:

first timing means timing said predetermined amount of time after receipt of said pre-trigger signal and then generating a first pulse that is applied to said second input to change it from its first state to its second state and

second timing means started after said first timing means has timed said predetermined amount of time for timing said blanking pulse signal width and then generating a second pulse that is applied to said reset input to change it from its second state to its first state to end said blanking pulse signal.

6. The signal processing system in accordance with claim 5 wherein said EMS transmitters comprise a radar transmitter, a navigation transmitter or a communication transmitter.

7. The signal processing system in accordance with claim 6 further comprising a control processor adapted to controlling the first signal router, signal processor circuits, second signal router, first timing means and second timing means.

8. The signal processing system in accordance with claim 1 further comprising a control processor adapted to controlling the first signal router, signal processor circuits and second signal router.

9. A method for processing signals comprising the steps of:

(a) receiving a pre-trigger signal from ones of a plurality of EMS transmitters a predetermined amount of time before they transmit;

(b) timing a first interval equal to said predetermined amount of time responsive to each said pre-trigger signal;

(c) commencing the generation of a blanking pulse signal at the end of timing each said first intervals in step (b);

(d) timing a second interval immediately after timing each said first intervals in step (b), said second time interval indicating the width of a blanking pulse signal; and

(e) terminating the generation of said blanking pulse signal commenced in step (c) at the end of timing a corresponding second interval in step (d);

wherein generated blanking pulse signals are sent to ones of said plurality of EMS receivers to protect them from signal interference caused by interference reflections of EMS signals that are transmitted by said one of said EMS transmitters and received at said EMS receivers by either rendering said EMS receivers incapable of receiving any EMS signals during the duration of each blanking pulse signal or by rendering said EMS receivers incapable of displaying any EMS signals during the duration of each blanking pulse signal.

10. The method for processing signals in accordance with claim 9 further comprising the steps of:

(f) routing the pre-trigger signal received in step (a) to at least one of a plurality of logic circuits which are used to generate said blanking pulse signals; and

(g) routing the blanking pulse signal generated in steps (c) and (e) by said at least one of a plurality of logic circuits responsive to a pre-trigger signal in step (f) to at least one of said plurality of EMS receivers to thereby protect said EMS receiver from said signal interference caused by said interference signal reflections.

11. The method for processing signals in accordance with claim 10 further comprising the steps of:

(h) storing said first interval timed in step (b) for each of said plurality of EMS transmitters;

(i) storing said second interval timed in step (d) for each of said plurality of EMS receivers;

(j) retrieving said first interval stored in step (h) associated with an EMS transmitter whose pre-trigger signal is received in step (a); and

(k) retrieving said second interval stored in step (i) associated with each EMS receiver to receive a blanking pulse signal generated in steps (c) through (e);

wherein each retrieved first interval and second interval are used by one of said logic circuits to generate a blanking pulse signal, said logic circuits each having two inputs, a reset input and an output.

12. The method for processing signals in accordance with claim 11 further comprising the steps of:

(l) timing said first interval of time using the first time retrieved in step (j) and

(m) timing said second interval of time using the second time retrieved in step (k).

13. The method for processing signals in accordance with claim 9 further comprising the steps of:

(f) storing the time of said first interval timed in step (b) for each of said plurality of EMS transmitters;

(g) storing the time of said second interval timed in step (d) for each of said plurality of EMS receivers;

(h) retrieving the time of said first interval stored in step (f) associated with an EMS transmitter whose pre-trigger signal is received in step (a); and

(i) retrieving the time of said second interval stored in step (g) associated with each EMS receiver to receive a blanking pulse signal;

wherein said retrieved first intervals and second intervals are used in conjunction with ones of a plurality of logic circuits to generate said blanking pulse signals.

14. The method for processing signals in accordance with claim 13 further comprising the steps of:

(j) timing said first interval of time using the time interval retrieved in step (h) and

(k) timing said second interval of time using the time interval retrieved in step (i).

15. The method for processing signals in accordance with claim 14 further comprising the steps of:

(l) setting a first of said two inputs of one of said logic circuits responsive to receipt of a pre-trigger signal from ones of said plurality of EMS transmitters;

(m) setting a second of said two inputs of said one of said logic circuits at the end of timing said first period in step (j);

(n) setting said output of said one of said logic circuits upon setting both its said first input and said second input in steps (l) and (m), said output of said logic circuit being set providing said blanking pulse signal; and

(o) resetting said output of said one of said logic circuits at the end of timing the second period timed in step (k) to terminate said blanking pulse signal.

16. The method for processing signals in accordance with claim 9 further comprising the steps of:

(f) setting a first of said two inputs of one of said logic circuits responsive to receipt of a pre-trigger signal from ones of said plurality of EMS transmitters;

(g) setting a second of said two inputs of said one of said logic circuits at the end of timing said first interval in step (j);

(h) setting said output of said one of said logic circuits upon setting both its said first input and said second input in steps (l) and (m), said output of said logic circuit being set providing said blanking pulse signal; and

(i) resetting said output of said one of said logic circuits at the end of timing the second interval timed in step (k) to terminate said blanking pulse signal.

17. Apparatus for aligning a signal processing system comprising:

memory storing first values indicating a predetermined amount of time following each pre-trigger signal received from each of a plurality of EMS transmitters after which predetermined amount of time said EMS transmitters transmits an EMS signal and storing second values indicating the duration of blanking pulse signals to be generated at the end of each said predetermined amount of time, said blanking pulse signals being routed to ones of a plurality of EMS receivers to protect them from signal interference caused by interference reflections of EMS signals transmitted by said EMS transmitters and received at said EMS receivers;

a comparator comparing said blanking pulse signals routed to said EMS receivers with said EMS signals received by said EMS receivers to detect misalignment between said blanking pulse signals and said received EMS signals that result in the EMS receivers not being protected from said signal interference; and

a calibrator adapted to change said first values and said second values stored in said memory for each EMS transmitter in order to align said blanking pulse signals generated using said stored first and second values with the EMS signals received by corresponding ones of said EMS receivers to remove said signal interference at said EMS receivers by either rendering said EMS receivers incapable of receiving any EMS signals during the duration of each blanking pulse signal or by rendering said EMS receivers incapable of displaying any EMS signals during the duration of each blanking pulse signal.

18. The apparatus for aligning a signal processing system of claim 17 further comprising:

first input apparatus adapted to provide a first correction signal indicating to increase or decrease said first value stored in said memory for each EMS transmitter to align the start of each blanking pulse signal with the start of each transmitted EMS signal as received at a corresponding EMS receiver and

second input apparatus adapted to provide a second correction signal indicating to increase or decrease said second value stored in said memory for each EMS transmitter to align the width of each blanking pulse signal with the width of each transmitted EMS signal as received at the last mentioned EMS receiver.

19. The apparatus for aligning a signal processing system of claim 18 further comprising:

memory writing means responsive to both said first and said second input apparatus for changing both said first value stored in said memory per said first correction signal and for changing said second value stored in said memory per said second correction signal;

wherein when said first value and/or when said second value stored in said memory for an EMS transmitter are changed it causes subsequently generated blanking pulse signals using both said values to remove said signal interference caused by said transmitted EMS signals at the one of said EMS receivers receiving the last mentioned blanking pulse signals.

20. The apparatus for aligning a signal processing system of claim 19 wherein said comparator comprises a video display displaying said blanking pulse signals generated using said first and said second values stored in said memory for a particular EMS transmitter and displaying the transmitted EMS signals from said last mentioned EMS transmitter as received at the one of said EMS receivers receiving the last mentioned blanking pulse signals and any non-alignment between the two signals is visibly seen.

21. The apparatus for aligning a signal processing system of claim 20 wherein said calibrator adapted to changing said stored first values and said stored second values comprises icons indicating to increase or decrease said stored first value and said stored second value for any chosen EMS transmitter and a user touches these icons after viewing a blanking pulse signal and a received EMS signal at an EMS receiver on said video display in order to align said blanking pulse signal with the received EMS signal and thereby remove said signal interference.

22. The apparatus for aligning a signal processing system of claim 17 wherein said comparator comprises a video display displaying said blanking pulse signal generated using said first and said second values stored in said memory for a particular EMS transmitter and displaying the transmitted EMS signal from said last mentioned EMS transmitter as received at the ones of said EMS receivers receiving the last mentioned blanking pulse signals and any non-alignment between the two signals is visibly seen.

23. The apparatus for aligning a signal processing system of claim 22 wherein said calibrator adapted to changing said stored first values and said stored second values comprises icons indicating to increase or decrease said stored first value and said stored second value for any chosen EMS transmitter and a user touches these icons after viewing a blanking pulse signal and a received EMS signal at an EMS receiver on said video display in order to align said blanking pulse signal with the received EMS signal and thereby remove said signal interference.

24. The apparatus for aligning a signal processing system of claim 22 wherein said video display is a Touch Screen Display and said icons are displayed on said Touch Screen Display and used by a user to configuration and align said EMS transmitters to work with said apparatus for aligning a signal processing system, one of said icons is used to select any particular EMS transmitter the pre-trigger signals for which are sent to said apparatus for aligning a signal processing system and once an EMS transmitter is so selected a plurality of information concerning said last mentioned EMS transmitter is displayed including said first and second values stored in said memory, the receiver(s) to receive a blanking pulse signal when said last mentioned EMS transmitter transmits an EMS signal and others of said icons are used to change said first and second values for alignment of blanking pulse signals and received EMS signals at corresponding receivers.

25. The apparatus for aligning a signal processing system of claim 17 further comprising:

memory writing means adapted to changing said first value stored in said memory and for changing said second value stored in said memory;

wherein when said first value and/or said second value stored in said memory for each EMS transmitter are changed it causes subsequently generated blanking pulse signals to remove said signal interference at particular ones of said EMS receivers caused by said transmitted EMS signals from said last mentioned EMS transmitters.

26. A method for aligning a signal processing system comprising the steps of:

(a) storing a first value for each of a plurality of EMS transmitters, said first value indicating a predetermined amount of time after each said EMS transmitter generates a pre-trigger signal before they transmit an EMS signal;

(b) storing at least one second value for each of said plurality of EMS transmitters, said second value indicating the duration of a blanking pulse signal generated starting at the end of said predetermined amount of time indicated by said first value stored in step (a) and said blanking pulse signal is forwarded to and used by an EMS receiver that experiences signal interference caused by EMS signals transmitted by an EMS transmitter to remove said interference by either rendering said EMS receivers incapable of receiving any EMS signals during the duration of each blanking pulse signal or to render said EMS receivers incapable of displaying any EMS signals during the duration of each blanking pulse signal;

(c) comparing said blanking pulse signals forwarded to and used by said EMS receivers with the EMS signals transmitted by said EMS transmitters as received by said EMS receivers to detect misalignment between the two last mentioned signals that causes said signal interference; and

(d) modifying said first value and said second value to change the starting time and duration of a blanking pulse signal so there is no misalignment between said blanking pulse signals and said last mentioned EMS signals.

27. The method for aligning a signal processing system of claim 26 further comprising the steps of:

(e) providing a first signal indicating to increase or decrease the first value stored in step (a) for each of said plurality of EMS transmitters indicating the predetermined amount of time; and

(f) providing a second signal indicating to increase or decrease the second value stored in step (b) for each of said plurality of EMS transmitters indicating the width of the blanking pulse signal.

28. The method for aligning a signal processing system of claim 27 wherein step (d) comprises the steps of:

(g) changing the first value stored in step (a) using the first signal provided in step (e); and

(h) changing the second value stored in step (b) using the second signal provided in step (f),

wherein changing the first value in step (g) and changing the second value in step (h) causes the generated blanking pulse signals to remove the signal interference at the EMS receivers caused by the EMS signals transmitted by the associated EMS transmitters.

29. The method for aligning a signal processing system of claim 28 further comprising the step of:

(i) generating a first video display displaying said blanking pulse signal generated using said first and said second values stored in said memory for any particular EMS transmitter and displaying the transmitted EMS signal from said last mentioned EMS transmitter as received at a particular one of said EMS receivers and any non-alignment between the two signals is visibly seen on said first video display.

30. The method for aligning a signal processing system of claim 29 further comprising the step of:

(j) generating a second video display, along with said first video display, on a touch screen monitor, said second video display displaying icons used to increase or decrease said stored first value and said stored second value for any particular EMS transmitter and a user touches these icons after viewing said blanking pulse signal and said received EMS signal displayed in step (i) to increase or decrease said stored first and second values in order to align said blanking pulse signal with said received EMS signal and thereby remove said signal interference.

31. The method for aligning a signal processing system of claim 30 further comprising the step of:

(k) generating a third video display, along with said first and second video display, on said touch screen monitor, said third video display being a icon that is keyed to select any particular EMS transmitter the pre-trigger signals from which are sent to said signal processing system and once an EMS transmitter is so selected a plurality of information concerning said EMS transmitter is displayed on said touch screen monitor including said first and second values stored in said memory and the receiver(s) to receive a blanking pulse signal when said last mentioned EMS transmitter transmits an EMS signal.

32. The method for aligning a signal processing system of claim 26 wherein step (d) comprises the steps of:

(e) changing the first value stored in step (a) as necessary to align said blanking pulse signal with said transmitted and received EMS signal; and

(f) changing the second value stored in step (b) as necessary to align said blanking pulse signal with said transmitted and received EMS signal;

wherein changing the first value in step (e) and changing the second value in step (f) causes blanking pulse signals generated using said values to remove signal interference at the EMS receivers caused by EMS signals transmitted by an associated EMS transmitter.

33. The method for aligning a signal processing system of claim 26 further comprising the step of:

(e) generating a first video display displaying said blanking pulse signal generated using said first and said second values stored in said memory for any particular EMS transmitter and displaying the transmitted EMS signal from said last mentioned EMS transmitter as received at a particular one of said EMS receivers and any non-alignment between the two signals is visibly seen on said first video display.

34. The method for aligning a signal processing system of claim 33 further comprising the steps of:

(f) generating a second video display, along with said first video display, on a touch screen monitor, said second video display displaying icons used to increase or decrease said stored first value and said stored second value for any particular EMS transmitter and a user touches these icons after viewing said blanking pulse signal and said received EMS signal displayed in step (e) to increase or decrease said stored first and second values in order to align said blanking pulse signal with said received EMS signal and thereby remove said signal interference;

(g) displaying a icon that is keyed to select any particular EMS transmitter the pre-trigger signals from which are sent to said signal processing system and once an EMS transmitter is so selected a plurality of information concerning said EMS transmitter is displayed on said touch screen monitor including said first and second values stored in said memory and the receiver(s) to receive a blanking pulse signal when said last mentioned EMS transmitter transmits an EMS signal; and

(h) displaying icons used to initially configure an EMS transmitter to work with said signal processing system.

35. A signal processing system comprising:

a first section adapted to detect at least one pre-trigger signal, wherein said pre-trigger signal is a signal which is sent by one or more radio frequency transmitters prior to a radio frequency signal transmission, wherein said pre-trigger signal indicates one of a category of radio frequency transmitter and receiver combinations and is used to create a blanking pulse signal;

a second section having a plurality of first circuits, each of said first circuits being adapted to generate a blanking pulse signal having a given width at a predetermined amount of time after receiving said pre-trigger signal;

a third section adapted to store signal characteristic data associated with said one or more radio frequency transmitters and receivers, wherein said signal characteristic data is used by said second section to determine and generate said blanking pulse signals associated with said radio frequency transmitter and receiver combinations such that different blanking pulse signals are generated for different said types of radio frequency transmitter and receiver combinations;

a fourth section adapted to route one or more said pre-trigger signals to one or more said first circuits; and

a fifth section adapted to route one or more of said blanking pulse signals generated by said first circuits to at least one of a plurality of radio frequency receivers based on either which input port said pre-trigger signal was received or said type of radio frequency transmitter and receiver combination which is associated with one or more said pre-trigger signals.

36. A signal processing system as in claim 35, wherein said pre-trigger signal is a leading edge of a digital signal.

37. A signal processing system as in claim 36, wherein said fourth and fifth sections comprise one or more programmable logic devices including field programmable gate arrays.

38. A signal processing system as in claim 37, wherein said second section further comprises a timing section used to generate a signal to halt each of said blanking pulse signals associated with each of said receivers, wherein said data in said third section is used to determine said signal to halt and when to halt it.

39. A signal processing system as in claim 38, wherein said blanking pulse signals are generated by said second section a predetermined amount of time after detection of a pre-trigger signal by said first section.

40. A signal processing system as in claim 39, wherein ones of said first circuits in said second section generate blanking pulse signals that causes at least one of said radio frequency receiver'"'"'s inputs to be blanked.

41. A signal processing system as in claim 40, wherein ones of said first circuits in said second section generate a blanking pulse signal that causes at least one of said radio frequency receiver'"'"'s inputs to be disabled.

42. A signal processing system as in claim 41, wherein ones of said first circuits in said second section generate a blanking pulse signal that causes the momentary disconnection of an antenna coupled to at least one of said radio frequency receivers.

43. A signal processing system as in claim 38, wherein said timing section comprises a first and a second timer portion, wherein said first timer portion is enabled upon receipt of at least one said pre-trigger signal and times the pre-determined amount of time to start a blanking pulse when said radio frequency transmitter that transmitted said last mentioned trigger signal starts transmitting at the end of the pre-determined amount of time;

and said second timer portion is enabled at the end of said pre-determined amount of time to time an interval that defines the width of a blanking pulse signal that occurs at the same time that said radio frequency transmitter is transmitting.

44. A signal processing system comprising:

a first and second routing control system, said first routing control system is adapted to receive and route at least one of a plurality of first signals received from one or more electromagnetic spectrum transmitters, said second routing control system is adapted to selectively route one or more of a second plurality of signals to one or more of a plurality of electromagnetic receivers;

a plurality of blanking control elements selectively coupled to said first and second routing control system adapted to produce said second plurality of signals and selectively input said second plurality of signals into said second routing control system;

a data structure adapted to store a plurality of data comprising signal characteristics associated with said electromagnetic transmitters and receivers including data associated with said first plurality of signals, a plurality of first and second signal delay data, transmitter identifier data, receiver identifier data, a plurality of first and second pulse width data, blanking control element identifier and assignment data, port assignment data,

a processing system adapted to selectively couple circuits between said first and second routing control system and said plurality of blanking control elements, control said plurality of blanking control elements and control coupling of said second routing control system with said one or more plurality of electromagnetic receivers;

a third routing control system coupled to said signal analyzer adapted to selectively couple with at least one of a plurality of said electromagnetic spectrum transmitters adapted to receive at least said third plurality of signals;

a user interface adapted to permit input of data and control operations of said signal processing system; and

a signal analyzer coupled to said first routing control system and said processing system adapted to analyze said first plurality of signals, said second plurality of signals and said third plurality of signals, wherein said signal analyzer produces comparison data or signals including data or signals based on a comparison of said second and third plurality of signals;

wherein said processing system controls said first, second and third routing control system and said plurality of blanking control elements based on signals or data from said signal analyzer, said user interface, said plurality of data in said data structure, and signal comparisons produced by said signal analyzer including comparisons of said second and third plurality of signals.

45. A signal processing system as in claim 44, wherein said blanking control elements are controlled by said processing system to perform blanking pulse tuning, said tuning based on receiving inputs from said first and second routing control systems such that the blanking control elements controls, creates and tunes blanking signals based on signal characteristics associated with one or more said electromagnetic transmitter/receiver pairs where the receiver receives interference signals from said transmitter.

46. A signal processing system as in claim 44, wherein said at least one of a first plurality of signals comprises a pre-trigger signal associated with said electromagnetic transmitter.

47. A signal processing system as in claim 44, wherein said second plurality of signals is a blanking signal adapted to blank or mask a signal received by one or more said electromagnetic receivers.

48. A signal processing system as in claim 44, wherein said third plurality of signals comprise output signals from one or more said electromagnetic receivers.

49. A signal processing system as in claim 44, wherein said blanking control elements comprise field programmable gate arrays, programmable logic arrays, application specific integrated circuit or a software implemented program run on a general processing integrated circuit system.