Adaptive array with automatic loop gain control

• US 5,608,409 A
• Filed: 03/28/1995
• Issued: 03/04/1997
• Est. Priority Date: 03/28/1995
• Status: Expired due to Term

• Current Assignee: Rilling, Kenneth F.
• Original Assignee: Rilling, Kenneth F.
• Inventors: Rilling, Kenneth F.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US08/411,290
• Time in Patent Office: 707 Days
• Field of Search: 342/375, 342/378, 342/379, 342/380, 342/383
• US Class Current: 342/380
• CPC Class Codes: G01S 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/2611 Means for null steering; Adaptive interference nulling
• CPC Class Codes: H04B 1/126 having multiple inputs, e.g. auxiliary antenna for receiving interfering signal aerials in general H01Q
• CPC Class Codes: H04B 7/0845 per branch equalization, e.g. by an FIR-filter or RAKE receiver per antenna branch rake receivers as such H04B1/7115
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

Adaptive arrays with an adaptive loop gain control to reduce the degradation in performance in reducing the effects of multipath and interference in communications receivers when the gain of the adaptive loops change with a change in the input signal level of the adaptive array. As the input signal level to the adaptive array changes, the adaptive loop gain control reduces the change in the adaptive loop gain to improve adaptive array performance.

Claims

1. A method for automatically controlling the gain of adaptive loops of an adaptive array to reduce the effects of a desired signal with multiple images with different delay times and of interference of input signals of said adaptive array with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of said adaptive loops due to changes in the input signal level of said adaptive array to improve said performance of said adaptive array, said adaptive array includes a feedback function coupled to receive the adaptive array output signal to generate the feedback signal, said method comprising the steps of:

a. detecting the signal strength of a representation of at least one of said input signals of said adaptive array to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain of said adaptive loops;

b. lowpass filtering said control signal of step a. to generate a lowpass filtered control signal; and

c. adjusting said gain of said adaptive loops with said lowpass filtered control signal of step b. to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

2. A method as in claim 1, wherein said feedback function includes a feedback function for a CMA adaptive array to generate said feedback signal.

3. A method as in claim 1 wherein said feedback function includes the steps of:

d. generating a reference signal which is correlated to said desired signal from said adaptive array output signal;

e. subtracting said adaptive array output signal from said reference signal of step d. to generate said feedback signal.

4. A method for automatically controlling the gain of adaptive loops of an adaptive array having a plurality of input signals to reduce the effects of a desired signal with multiple images with different delay times and of interference received by said adaptive array with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of said adaptive loops due to changes in the input signal level of said adaptive array, said adaptive array includes a feedback function coupled to receive said adaptive array output signal to generate the feedback signal, said method comprising the steps of:

a. detecting the signal strength of a representation of at least one input signal of said adaptive array to generate a control signal;

b. lowpass filtering said control signal of step a. to generate a lowpass filtered control signal; and

c. adjusting the amplitude of each input signal of said adaptive array to reduce the change in said input signal level of said adaptive array with said lowpass filtered control signal of step b. to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

5. A method as in claim 4, wherein said feedback function includes a feedback function for a CMA adaptive array to generate said feedback signal.

6. A method as in claim 4 wherein said feedback function includes the steps of:

d. generating a reference signal which is correlated to said desired signal from said adaptive array output signal;

e. subtracting said adaptive array output signal from said reference signal of step d. to generate said feedback signal.

7. A method for automatically controlling the gain of the adaptive loops of an adaptive array used in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of said adaptive loops due to changes in the input signal level of said adaptive array to improve said performance of said adaptive array, with each of said input signals of said adaptive array generated from the output signal of the associated one of said antenna elements, said adaptive array includes a separate multiplier associated with each one of said adaptive loops coupled to the associated one of said input signals of said adaptive array and the feedback function for a CMA adaptive array coupled to receive said adaptive array output signal to generate the feedback signal, said method comprising the steps of:

a. detecting the signal strength of a representation of at least one of said input signals of said adaptive array to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain of said adaptive loops;

b. lowpass filtering Said control signal of step a. to generate a lowpass filtered control signal; and

c. adjusting said gain of said adaptive loops with said lowpass filtered control signal of step b. to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

8. A method as in claim 7 wherein:

step a. includes the steps of;

d. summing at least two of said input signals of said adaptive array to generate a summed signal;

e. squaring said summed signal of step d. to generate a representative signal representing said input signal level of said adaptive array;

f. lowpass filtering said representative signal of step e. to provide further averaging and a lowpass filtered signal; and

g. taking the square root of said lowpass filtered signal of step f. to generate said control signal; and

step c. includes the step of changing the voltage gain of the adaptive loops linearly with respect to the voltage level of said control signal;

wherein said feedback function for a CMA adaptive array includes a first amplitude limiter coupled to receive said adaptive array output signal to generate said feedback signal; and

wherein said adaptive array further includes a second amplitude limiter associated with each said multiplier coupled to receive said associated one of said input signals of said adaptive array to generate an amplitude limited input signal coupled to be received by associated said multiplier.

9. A method as in claim 7 wherein:

step a. includes the steps of;

h. separately squaring at least two of said input signals of said adaptive array to generate squared signals;

i. summing said squared signals in step h. to generate said control signal; and

step c. includes the step of linearly changing the power gain of the adaptive loops with respect to the voltage level of said control signal;

wherein said feedback function for a CMA adaptive array includes a first amplitude limiter coupled to receive said adaptive array output signal to generate said feedback signal; and

wherein said adaptive array further includes a second amplitude limiter associated with each said multiplier associated with one of said input signals of said adaptive array coupled to receive said associated one of said input to generate an amplitude limited input signal coupled to be received by associated said multiplier.

10. A method as in claim 7 wherein:

said adaptive array further includes;

a computing system; and

an algorithm representation of said adaptive array and said direct ALGC;

step a. further includes the steps of;

j. generating a digital representation of said control signal; and

k. generating a digital representation of each of said input signals of said adaptive array; and

said method further includes the step of;

l. computing a real time digital representation of said adaptive array output signal from said digital representation of said control signal of step j. and said digital representation of each of said input signals of step k. with said computing system and said algorithm.

11. A method as in claim 7 wherein said feedback function for a CMA adaptive array includes the step of amplitude limiting said adaptive array output signal to generate said feedback signal.

12. A method as in claim 7 wherein said feedback function for a CMA adaptive array includes the step of directly connecting said adaptive array output signal to the output of said feedback function for a CMA adaptive array to make said adaptive array output signal said feedback signal.

13. A method as in claim 7, wherein said communications receiver system includes a constant envelope modulation system.

14. A method for automatically controlling the gain of the adaptive loops of an adaptive array used in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of said adaptive loops due to changes in the input signal level of said adaptive array to improve said performance of said adaptive array, with each of input signals of said adaptive array generated from the output signal of the associated one of said antenna elements, said adaptive array includes a different multiplier associated with each one of said adaptive loops coupled to the associated one of said input signals and a feedback function coupled to receive said adaptive array output signal to generate the feedback signal, said method comprising the steps of:

a. detecting the signal strength of a representation of at least one of said input signals of said adaptive array to generate a control signal;

b. lowpass filtering the control signal to generate a lowpass filtered control signal; and

c. adjusting the amplitude of each one of said input signals of said adaptive array to reduce the change in said input signal level of said adaptive array with said lowpass filtered control signal of step b. to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

15. A method as in claim 14 wherein:

step a. includes the steps of;

d. separately squaring at least two of said input signals of said adaptive array to generate squared signals;

e. summing said squared signals in step d. to generate a said control signal signal; and

said gain control includes a variable power attenuator; and

step c. includes the step of adjusting said gain of each variable power attenuator gain control in a feedback manner.

16. A method as in claim 14, wherein said feedback function includes the step of amplitude limiting said adaptive array output signal to generate said feedback signal.

17. A method as in claim 14, wherein said feedback function includes the steps of:

f. amplitude limiting said adaptive array output signal to generate an amplitude limited signal;

g. envelope detecting said adaptive array output signal to generate an envelope signal representation of the voltage signal level of said adaptive array output signal;

h. generating a bias voltage signal;

i. subtracting said bias voltage signal of step h. from said envelope signal of step g. to generate the biased envelope signal; and

j. multiplying said amplitude limited signal of step f. and said biased envelope signal of step i. to generate said feedback signal.

18. A method as in claim 14, wherein said communications receiver system includes a constant envelope modulation system.

19. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights coupled to each said input terminal of said adaptive array, a first adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function for a CMA adaptive array coupled to receive said adaptive array output signal to generate the feedback signal, a separate first multiplier associated with each of said weights, each said first multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

a direct ALGC including;

a detector having at least one input terminal and an output terminal, with each input terminal of said detector disposed to be coupled to associated said input terminal of said adaptive array to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain of said adaptive loops at said output terminal of said detector; and

a gain control having first and second input terminals and one output terminal, said first input terminal disposed to be coupled to receive said feedback signal, said output terminal disposed to be coupled to said second input terminal of each said first multiplier, and said second input terminal of said gain control coupled to said output terminal of said detector to receive said control signal to adjust said gain of said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

20. A system as in claim 19 wherein said feedback function for a CMA adaptive array includes an amplitude limiter.

21. A system as in claim 19 wherein said feedback function includes:

an envelope detector with an input terminal and an output terminal with said input terminal coupled to said output terminal of said first adder to receive said adaptive array output signal to generate a signal representative of the level of said adaptive array output;

a voltage source having an output terminal to generate a bias voltage signal;

a subtractor having a first and a second input terminal and an output terminal with said first input terminal coupled to said output terminal of said envelope detector and said second input terminal coupled to said output terminal of said voltage source to subtract said bias signal from said signal representative of the level of said adaptive array output signal to generate a biased envelope signal;

an amplitude limiter with an input terminal and an output terminal with said input terminal coupled to said output terminal of said first adder to receive said adaptive array output signal to generate an amplitude limited signal; and

a second multiplier with first and second input terminals and an output terminal, where said first input terminal is coupled to said output terminal of said subtractor and said second input terminal is coupled to said output terminal of said amplitude limiter to multiple said biased envelope signal and said amplitude limited signal to generate said feedback signal.

22. A system as in claim 19 wherein said feedback function for a CMA adaptive array has an input terminal and an output terminal with said input terminal connected to said output terminal.

23. A system as in claim 19 further includes an individual amplitude limiter associated with each of said weights, each said amplitude limiter having an input and an output terminal with said input terminal disposed to be coupled to an input of the associated one of said weights and said output terminal of said amplitude limiter is coupled to said first input terminal of said first multiplier associated with same one of said weights.

24. A system as in claim 19 wherein:

said detector includes;

a second adder having a plurality of input terminals and one output terminal with each of said input terminals disposed to be coupled to a different one of said N antenna elements to generate a summed signal;

a third multiplier having first and second input terminals and an output terminal, said first and second input terminals coupled to said output terminal of said second adder to square said summed signal to generate the squared summed signal at said output terminal of said third multiplier;

a lowpass filter having an input terminal and an output terminal, with said input terminal coupled to said output terminal of said third multiplier to lowpass filter said squared summed signal; and

a square root circuit having an input terminal and an output terminal, said input terminal coupled to said output terminal of said lowpass filter to generate the control signal at said output terminal of said square root circuit; and

said gain control includes a fourth multiplier having first and second input terminals and an output terminal with said first input terminal of said fourth multiplier being said first input terminal of said gain control and said second input terminal of said fourth multiplier being said second input terminal of said gain control and with said output terminal forming the output terminal of said gain control;

said feedback function for CMA adaptive array includes an amplitude limiter; and

said adaptive array further includes an individual amplitude limiter associated with each one of said weights, each said amplitude limiter having an input and an output terminal with said input terminal disposed to be coupled to said input of the associated one of said weights and said output terminal of said amplitude limiter coupled to said first input terminal of said first multiplier associated with the same associated one of said weights.

25. A system as in claim 19 wherein:

said detector includes;

a second adder with a plurality of input terminals and one output terminal with each of said input terminals disposed to be coupled to a different one of said N antenna elements to generate a summed signal applied to said output terminal of said adder; and

a power detector with input and output terminals with said input terminal coupled to said output terminal of said second adder to generate a control signal representative of the power level of said summed signal with said control signal applied to said output terminal of said power detector; and

said gain control changes the power gain of the feedback signal;

said feedback function for CMA adaptive array includes an amplitude limiter; and

said adaptive array further includes an individual amplitude limiter associated with each one of said weights, each said amplitude limiter having an input and an output terminal with said input terminal disposed to be coupled to said input of the associated one of said weights and said output terminal of said amplitude limiter coupled to said first input terminal of said first multiplier associated with the same associated one of said weights.

26. A system as in claim 19, wherein:

said system further includes;

a first analog-to-digital converter having an input terminal and a control signal output data port with said input terminal disposed to be coupled to said output terminal of said detector to generate a digital representation of said control signal; and

said adaptive array further includes;

N second analog-to-digital converters having an input terminal and an output digital data port with said input terminal of each of said N second analog-to-digital converters disposed to be coupled to a different one of each of said N antenna elements to generate a digital representation of each said input signal of said adaptive array; and

a computing system having N input signal digital data ports, one input control signal digital data port and one output signal digital data port with each of said N input signal digital data ports coupled to said output signal digital data port of a different one of each of said second N analog-to-digital converters and said input control signal digital data port of said computing system coupled to said output control signal digital data port of said first analog-to-digital converter, said computing system computing a real time digital representation of said adaptive array output signal with an algorithm representation of said adaptive array and said direct ALGC with said digital representation of said adaptive array output signal applied to said output digital data port of said computing system.

27. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights coupled to each said input terminal of said adaptive array, an adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function coupled to receive said adaptive array output signal to generate the feedback signal, said feedback function including generation of a reference signal which is correlated to said desired signal from said adaptive array output signal and subtracting said adaptive array output signal from said reference signal to generate said feedback signal, a separate multiplier associated with each of said weights, each said multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

a direct ALGC including;

a detector having at least one input terminal and an output terminal, with each input terminal of said detector disposed to be coupled to the associated said input terminal of said adaptive array to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain of said adaptive loops at said output terminal of said detector; and

a gain control having first and second input terminals and one output terminal, said first input terminal disposed to be coupled to receive said feedback signal, said output terminal disposed to be coupled to said second input terminal of each said multiplier, and said second input terminal of said gain control coupled to said output terminal of said detector to receive said control signal to adjust said gain of said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

28. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights coupled to each said input terminal of said adaptive array, an adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function for a CMA adaptive array coupled to receive said adaptive array output signal to generate the feedback signal, a separate multiplier associated with each of said weights, each said multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

a direct ALGC including;

a detector having an input terminal and an output terminal, with each input terminal of said detector coupled to receive said adaptive array output signal to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain of said adaptive loops at said output terminal of said detector; and

a gain control having first and second input terminals and one output terminal, said first input terminal disposed to be coupled to receive said feedback signal, said output terminal disposed to be coupled to said second input terminal of each said multiplier, and said second input terminal of said gain control coupled to said output terminal of said detector to receive said control signal to adjust said gain of said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

29. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a separate plurality of weights with each of said weights having a first and second input terminal with said first input terminal coupled to each associated said input terminal of said adaptive array to selectively weight said received signals by selected weight factors, an adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function for a CMA adaptive array coupled to receive said adaptive array output signal to generate the feedback signal, a separate multiplier associated with each of said weights, each said multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

a direct ALGC including;

a detector having at least one input terminal and an output terminal, with each input terminal of said detector disposed to be coupled to the associated said input terminals of said adaptive array to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain to reduce said increased difference between gain and optimum gain of said adaptive loops at said output terminal of said detector; and

variable gain integrator networks, one variable gain integrator network associated with each said multiplier, wherein each of said variable gain integrator networks having first and second input terminals and an output terminal with said first input terminal coupled to said output terminal of said associated multiplier, said second input terminal of each one of said variable gain integrator networks disposed to be coupled to said output terminal of said detector to receive said control signal to adjust said gain of each said variable gain integrator networks to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops, and said output terminal of each of said variable gain integrator networks coupled to said second input terminal of the same one of said weights with which each one of said variable gain integrator networks is associated to control the generation of said select weight factor of said associated one of said weights.

30. An adaptive array as in claim 29 wherein each of said variable gain integrator networks includes:

a variable gain amplifier having first and second input terminals and an output terminal, said first input terminal being said first input terminal of said variable gain integrator network and is coupled to the output terminal of said associated multiplier and said second input terminal being said second input terminal of said variable gain integrator network disposed to be coupled to the output terminal of said detector; and

an RC integrator network with an input terminal and an output terminal, said input terminal coupled to said output terminal of said variable gain amplifier and said output terminal being said output terminal of said variable gain integrator network coupled to associated one of said weights.

31. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights coupled to each said input terminal of said adaptive array to selectively weight said received signals by selected weight factors, an adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function for a CMA adaptive array coupled to receive said adaptive array output signal to generate the feedback signal, a separate multiplier associated with each of said weights, each said multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

a direct ALGC including;

a detector having an input terminal and an output terminal, with each input terminal of said detector disposed to be coupled to receive said adaptive array output signal to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain of said adaptive loops at said output terminal of said detector; and

variable gain integrator networks, one variable gain integrator network associated with each said multiplier, wherein each of said variable gain integrator networks having first and second input terminals and an output terminal with said first input terminal coupled to said output terminal of said associated multiplier, said second input terminal of each one of said variable gain integrator networks disposed to be coupled to said output terminal of said detector to receive said control signal to adjust said gain of each said variable gain integrator networks to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops, and said output terminal of each of said variable gain integrator networks coupled to said second input terminal of the same associated one of said weights with which each one of said variable gain integrator networks is associated to control the generation of said select weight factor of said associated one of said weights.

32. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a separate plurality of weights with each of said weights having a first and second input terminal with said first input coupled to each associated said input terminal of said adaptive array to selectively weight said received signals by selected weight factors, an adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function for a CMA adaptive array coupled to receive said adaptive array output signal to generate the feedback signal, a separate multiplier associated with each of said weights, each said multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

a direct ALGC including;

a detector having at least one input terminal and an output terminal, with each input terminal of said detector disposed to be coupled to the associated said input terminal of said adaptive array to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain of said adaptive loops at said output terminal of said detector; and

a separate gain control associated with each one of said weights having first and second input terminals and one output terminal, said first input terminal coupled to the same said input terminal of said adaptive array associated with said associated one of said weights, said output terminal disposed to be coupled to said first input terminal of associated said multiplier, and said second input terminal of said gain control disposed to be coupled to said output terminal of said detector to receive said control signal to adjust said gain of each said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

33. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights with a first and second input terminal, said first input terminal of each of said weights coupled to the associated said input terminal of said adaptive array, a adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function for a CMA adaptive array coupled to receive said adaptive array output signal to generate the feedback signal, a separate multiplier associated with each of said weights, each said first multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

a direct ALGC including;

a detector having an input terminal and an output terminal, with each input terminal of said detector disposed to be coupled said adaptive array output signal to generate a control signal representing the relationship between said input signal level of said adaptive array and change of said gain of said adaptive loops at said output terminal of said detector; and

a separate gain control associated with each one of said weights having first and second input terminals and one output terminal, said first input terminal coupled to the same said input terminal of said adaptive array associated with said associated one of said weights, said output terminal disposed to be coupled to said first input terminal of associated said multiplier, and said second input terminal of said gain control disposed to be coupled to said output terminal of said detector to receive said control signal to adjust said gain of each said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops.

34. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights with a first and second input terminal, said first input terminal of each of said weights coupled to the associated said input terminal of said adaptive array, a first adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function coupled to receive said adaptive array output signal to generate the feedback signal, a separate first multiplier associated with each of said weights, each said first multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

an indirect ALGC including;

a separate gain control associated with each input terminal of said adaptive array, each having first and second input terminals and an output terminal, said first input terminal disposed to be coupled to associated one of said antenna elements, and said output terminal disposed to be coupled to said associated input terminal of said adaptive array; and

a detector having at least one input and an output terminal with each input terminal of said detector disposed to be coupled to said output terminal of the associated said gain control to generate a control signal and with said output terminal of said detector disposed to be coupled to said second input terminal of each said gain control to adjust the gain of each said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops by reducing the change in said input signal level of said adaptive array in a feedback manner.

35. A system as in claim 34 wherein said feedback function includes an amplitude limiter.

36. A system as in claim 34 wherein:

each said gain control includes a variable power attenuator gain control; and

said detector further includes;

a second adder having a plurality of input terminals and an output terminal with each of said input terminals disposed to be coupled to said output terminal of a different said variable power attenuator gain control to generate a summed signal;

a second multiplier having first and second input terminals and an output terminal, said first and second input terminals coupled to the output terminal of said second adder to square said summed signal; and

a lowpass filter having an input terminal and an output terminal with said input terminal coupled to said output terminal of said second multiplier to generate said control signal.

37. A system as in claim 34 further includes an individual amplitude limiter associated with each of said weights, each said amplitude limiter having an input and an output terminal with said input terminal disposed to be coupled to said associated one of said weights and said output terminal of each said amplitude limiter disposed to be coupled to said input terminal of said first multiplier associated with each of said associated weights.

38. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights coupled to each said input terminal of said adaptive array to selectively weight said received signals by selected weight factors, an adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function coupled to receive said adaptive array output signal to generate the feedback signal, said feedback function including generation of a reference signal which is correlated to said desired signal from said adaptive array output signal and subtracting said adaptive array output signal from said reference signal to generate said feedback signal, a separate multiplier associated with each of said weights, each said multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

an indirect ALGC including;

a separate gain control associated with each input terminal of said adaptive array, each having first and second input terminals and an output terminal, said first input terminal disposed to be coupled to associated one of said antenna elements, and said output terminal disposed to be coupled to said associated input terminal of said adaptive array; and

a detector having at least one input and an output terminal with each input terminal of said detector disposed to be coupled to said output terminal of the associated said gain control to generate a control signal and with said output terminal of said detector disposed to be coupled to said second input terminal of each said gain control to adjust the gain of each said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops by reducing the change in said input signal level of said adaptive array in a feedback manner.

39. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights coupled to each said input terminal of said adaptive array to selectively weight said received signals by selected weight factors, an adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function coupled to receive said adaptive array output signal to generate the feedback signal, a separate multiplier associated with each of said weights, each said multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

an indirect ALGC including;

a detector having an input and an output terminal with said input terminal coupled to said adaptive array output signal to generate a control signal; and

a separate gain control associated with each input terminal of said adaptive array, each having first and second input terminals and an output terminal, said first input terminal disposed to be coupled to associated one of said antenna elements, said output terminal disposed to be coupled to said associated input terminal of said adaptive array, and said second input terminal disposed to be coupled to said output terminal of said detector to adjust the gain of each said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops by reducing the change in said input signal level of said adaptive array in a feedback manner.

40. An automatic loop gain control system to improve the performance of an adaptive array included in a communications receiver system with a plurality of antenna elements to reduce the effects of multipath with the performance of said adaptive array degraded by an increased difference between the gain and the optimum gain of any of the adaptive loops of said adaptive array due to changes in the input signal level of said adaptive array, said adaptive array including a separate input terminal associated with each one of said antenna elements, a plurality of weights coupled to each said input terminal of said adaptive array to selectively weight said received signals by selected weight factors, a first adder coupled to receive the output signals of said weights to generate the adaptive array output signal, a feedback function coupled to receive said adaptive array output signal to generate the feedback signal, a separate first multiplier associated with each of said weights, each said first multiplier having a first and second input terminal and an output terminal, said automatic loop gain control system comprising:

an indirect ALGC including;

a separate gain control associated with each input terminal of said adaptive array, each having first and second input terminals and an output terminal, said first input terminal disposed to be coupled to associated one of said antenna elements, and said output terminal disposed to be coupled to said associated input terminal of said adaptive array; and

a detector having at least one input and an output terminal with each input terminal of said adaptive array disposed to be coupled to said input terminal of the associated said gain control to generate a control signal and with said output terminal of said detector disposed to be coupled to said second input terminal of each said gain control to adjust the gain of each said gain control to reduce said increased difference between said gain and said optimum gain of each of said adaptive loops by reducing the change in said input signal level of said adaptive array in a feedforward manner.

41. A system as in claim 40 wherein said feedback function includes an amplitude limiter.

42. A system as in claim 40 wherein:

said detector further includes;

a second adder having a plurality of input terminals and one output terminal with each of said input terminals disposed to be coupled to a different one of said input terminals of said adaptive array to generate a summed signal; and

a second multiplier having first and second input terminals and an output terminal, said first and second input terminals coupled to the output terminal of said second adder to square said summed signal;

a lowpass filter having an input terminal and an output terminal with said input terminal coupled to said output terminal of said second multiplier to generate the lowpass filtered signal; and

a square root circuit with an input and output terminal with said input terminal coupled to said output terminal of said lowpass filter to receive said lowpass filtered signal to generate said control signal; and

each said gain control includes a variable voltage attenuator gain control; and

said adaptive array further includes an individual amplitude limiter associated with each one of said weights, each said amplitude limiter having an input and an output terminal with said input terminal coupled to the associated one of said weights and said output terminal of said amplitude limiter coupled to said first input terminal of said first multiplier associated with the same associated one of said weights.

43. An adaptive array included in a communications receiver system with constant envelope modulation to reduce the effects of multipath and interference, said adaptive array comprising:

N antenna elements disposed to receive transmitted radio signals as an input signal where N is an integer of at least 2;

N tapped delay lines, one tapped delay line associated with each of said N antenna elements, wherein each tapped delay line has a single input terminal disposed to be coupled to said antenna element associated therewith and M output terminals, where M is an integer of at least 2;

L weights, where L equals the product of M times N and where a different one of said L weights is associated with a different one of said output terminals of said N tapped delay lines, wherein each of said L weights having a first and a second input terminal and an output terminal, said first input terminal of each of said L weights is coupled to the associated output terminal of said associated tapped delay line and wherein each of said L weights applies a select weight factor to the signal received on said first input terminal of each of said L weights;

a first adder having L input terminals and an output terminal, each of said input terminals is coupled to the output terminal of a different one of said L weights to generate an adaptive array output signal;

a first amplitude limiter having an input terminal and an output terminal, said input terminal coupled to said output terminal of said first adder to receive said adaptive array output signal to generate a feedback signal;

a direct ALGC, said direct ALGC comprising;

a detector having an output terminal and at least one input terminal with each input terminal of said detector disposed to be coupled to the associated one of said N antenna elements to generate a control signal at said output terminal of said detector; and

a gain control with a first and second input terminal and an output terminal, said first input terminal disposed to be coupled to said output terminal of said first amplitude limiter to receive said feedback signal and said second input terminal coupled to said output terminal of said detector to receive said control signal to adjust said gain of each of said adaptive loops;

L first multipliers, one first multiplier associated with each one of said L weights, wherein each of said L first multipliers have a first and a second input terminal and an output terminal with said first input terminal of each of said L first multipliers coupled to said associated output terminal of said associated tapped delay line and said second input terminal of each of said L first multipliers is coupled to said output terminal of said gain control; and

L integrators, one integrator associated with each of said L weights, wherein each integrator has an input terminal and an output terminal with said input terminal coupled to said output terminal of the same of each L first multipliers that is associated with the same of each of said L weights and said output terminal of each of said L integrators is coupled to said second input terminal of said associated one of said L weights to control the generation of said select weight factor of said associated one of said L weights.

44. An adaptive array as in claim 43 wherein:

said detector further includes;

a second adder having a plurality of input terminals and one output terminal with each of said input terminals disposed to be coupled to a different one of said N antenna elements to generate a summed signal;

a second multiplier having first and second input terminals and an output terminal, said first and second input terminals coupled to said output terminal of said second adder to square said summed signal to generate a squared signal at said output terminal of said second multiplier;

a lowpass filter having an input terminal and an output terminal, wherein said input terminal is coupled to said output terminal of said second multiplier to receive said squared signal to generate a lowpass filtered signal at said output terminal of said lowpass filter; and

a square root circuit having an input terminal and an output terminal, said input terminal coupled to said output terminal of said lowpass filter to receive said lowpass filtered signal to generate said control signal at said output terminal of said square root circuit; and

said gain control includes a third multiplier; and

said adaptive array further includes L second amplitude limiters, one second amplitude limiter associated with each of said output terminals of each of said tapped delay lines, wherein each second amplitude limiter has an input terminal and an output terminal, with said input terminal of each of said L second amplitude limiters coupled to the associated one of M output terminals of the associated one of N tapped delay lines to amplitude limit the received signal and said output terminal of each of said L second amplitude limiters is coupled to said first input terminal of said associated one of each of said L first multipliers.

45. A system as in claim 43 further includes L second amplitude limiters, one second amplitude limiter associated with each of said output terminals of each of said N tapped delay lines, wherein each second amplitude limiter has an input terminal and an output terminal, with said input terminal of each of said L second amplitude limiters coupled to the associated one of M output terminals of the associated one of said N tapped delay lines to amplitude limit the received signal and said output terminal of each of said L second amplitude limiters is coupled to said first input terminal of said associated one of each of said L first multipliers.

46. An adaptive array included in a communications receiver system with constant envelope modulation to reduce the effects of multipath and interference, said adaptive array comprising:

N antenna elements disposed to receive transmitted radio signals as an input signal where N is an integer of at least 2;

an indirect ALGC, said indirect ALGC comprising;

N gain controls, each having a first and a second input terminal and an output terminal, said first input terminal disposed to be coupled to said associated one of said N antenna elements;

a detector with an output terminal and at least one input terminal with each input terminal of said detector coupled to said output terminal of the associated one of said N gain controls to generate a control signal at said output terminal of said detector and with said output terminal disposed to be coupled to said second input terminal of each of said N gain controls to adjust the signal level of each of said N antenna elements in a feedback manner to reduce change in the input signal level of said adaptive array;

N tapped lines, one tapped delay line associated with each of said N antenna elements, wherein each tapped delay line has a single input terminal disposed to be coupled to said output terminal of one of said N gain controls associated with the same one of said N antenna elements and M output terminals, where M is an integer of at least 2;

L weights, where L equals the product of M times N and where a different one of said L weights is associated with a different one of said output terminals of said N tapped delay lines, wherein each of said L weights has a first and a second input terminal and an output terminal, said first input terminal is coupled to the associated output terminal of said associated one of said N tapped delay lines and each of said L weights applies a select weight factor to the signal received on said first input terminal of each of said L weights;

a first adder having L input terminals and an output terminal, each of said L input terminals being coupled to the output terminal of a different one of said L weights to generate an adaptive array output signal;

a first amplitude limiter having an input terminal and an output terminal, said input terminal coupled to said output terminal of said first adder to receive said adaptive array output signal and to generate a feedback signal;

L first multipliers, one first multiplier associated with each of said L weights, wherein each of said L first multipliers having a first and a second input terminal and an output terminal with said first input terminal of each of said L first multipliers coupled to said associated output terminal of said associated N tapped delay lines and said second input terminal of each of said L first multipliers coupled to said output terminal of said first amplitude limiter; and

L integrators, one integrator associated with each of said L weights, wherein each integrator has an input terminal and an output terminal with said input terminal coupled to said output terminal of the same of each of said L first multipliers that is associated with the same said of each of said L weights to which each of said integrator is associated and said output terminal is coupled to the second input terminal of the associated one of said L weights to control the generation of said select weight factor of said associated one of said L weights.

47. A system as in claim 46 wherein:

each of said N gain controls includes a variable power attenuator gain control; and

said detector further includes;

a second adder having a plurality of input terminals and an output terminal with each of said input terminals disposed to be coupled to said output terminal of a different said variable power attenuator gain control to generate a summed signal;

a second multiplier having first and second input terminals and an output terminal, said first and second input terminals coupled to the output terminal of said second adder to square said summed signal and generate a squared signal at said output terminal of said second multiplier; and

a lowpass filter having an input terminal and an output terminal with said input terminal coupled to said output terminal of said second multiplier to receive said squared signal to generate said control signal.

48. A system as in claim 46 further includes L second amplitude limiters, one second amplitude limiter associated with each of said output terminals of each of said tapped delay lines, wherein each second amplitude limiter has an input terminal and an output terminal, with said input terminal of each of said L second amplitude limiters coupled to the associated one of M output terminals of the associated one of N tapped delay lines to amplitude limit the received signal and said output terminal of each of said L second amplitude limiters is coupled to said first input terminal of said associated one of each of said L first multipliers.