Amplitude cancellation topology for multichannel applications

• US 20030069022A1
• Filed: 10/04/2001
• Published: 04/10/2003
• Est. Priority Date: 10/04/2001
• Status: Abandoned Application

• Current Assignee: Northrop Grumman Corporation
• Original Assignee: Northrop Grumman Corporation
• Inventors: Wade, James B., Kintis, Mark, Harnden, Robert R., Keller, Mark V.
• Application Number:
  US09/971,741
• Publication Number:
  US 20030069022A1
• Time in Patent Office: Days
• US Class Current: 455/452.1
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input

Abstract

A multichannel dynamic range adaptor (102) includes a multichannel signal input (116) for carrying an input signal with an input bandwidth spanning multiple communication channels, and a multichannel signal attenuator (118) connected to the multichannel signal input (116). The multichannel signal attenuator (118) includes a signal output (120) and a signal attenuation input (134) responsive to an attenuation control signal. The multichannel signal attenuator (118) is adapted to provide, on the signal output (120), an output signal corresponding to the input signal reduced in dynamic range in accordance with the attenuation control signal. The output signal dynamic range is generally constrained to be no greater than the dynamic range capability (e.g., 60 dB or less) of an analog to digital (A/D) converter (122) coupled to the multichannel signal attenuator (118) for digitizing the output signal.

Claims

1. A multichannel dynamic range adaptor comprising:

a multichannel signal input for carrying an input signal with an input bandwidth spanning multiple communication channels; and

a multichannel signal attenuator connected to the multichannel signal input, the multichannel signal attenuator comprising a signal output and a signal attenuation input responsive to an attenuation control signal;

whereby the multichannel signal attenuator is adapted to provide, on the signal output, an output signal corresponding to the input signal reduced in dynamic range in accordance with the attenuation control signal.

2. The multichannel dynamic range adaptor of claim 1, further comprising an analog to digital (A/D) converter coupled to the multichannel signal attenuator for digitizing the output signal, wherein output signal dynamic range is no greater than A/D converter dynamic range.

3. The multichannel dynamic range adaptor of claim 2, wherein the A/D converter is characterized by an A/D converter bandwidth at least equal to the input bandwidth.

5. The multichannel dynamic range adaptor of claim 1, wherein the multichannel signal attenuator is operative to subtract the attenuation control signal from the input signal.

6. The multichannel dynamic range adaptor of claim 1, wherein the input bandwidth spans at least 3 channels.

7. The multichannel dynamic range adaptor of claim 1, wherein the attenuation control signal includes signal attenuation information for multiple communication channels.

9. The multichannel dynamic range adaptor of claim 1, further comprising a first local oscillator and mixer for downconverting a received signal, and a first bandpass filter spanning the input bandwidth and coupled to the first mixer.

10. The multichannel dynamic range adaptor of claim 9, further comprising a second local oscillator and mixer coupled to the first bandpass filter for downconverting the output signal, and a second bandpass filter spanning the input bandwidth and coupled to the multichannel signal attenuator.

11. The multichannel dynamic range adaptor of claim 1, wherein the input signal is a radio frequency input signal.

4. A multichannel dynamic range adaptor comprising:

a multichannel signal input for carrying an input signal with an input bandwidth spanning multiple communication channels; and

a multichannel signal attenuator connected to the multichannel signal input, the multichannel signal attenuator comprising a signal output and a signal attenuation input responsive to an attenuation control signal;

whereby the multichannel signal attenuator is adapted to provide, on the signal output, an output signal corresponding to the input signal reduced in dynamic range in accordance with the attenuation control signal;

wherein the multichannel signal attenuator is a reactive power summer.

8. A multichannel dynamic range adaptor comprising:

a multichannel signal input for carrying an input signal with an input bandwidth spanning multiple communication channels; and

a multichannel signal attenuator connected to the multichannel signal input, the multichannel signal attenuator comprising a signal output and a signal attenuation input responsive to an attenuation control signal;

whereby the multichannel signal attenuator is adapted to provide, on the signal output, an output signal corresponding to the input signal reduced in dynamic range in accordance with the attenuation control signal;

wherein the attenuation control signal comprises scaled signal information from a prior input signal.

12. A method for modifying dynamic range of an input signal, the method comprising:

obtaining an input signal with an input bandwidth spanning multiple communication channels;

coupling the input signal through a multichannel signal attenuator; and

reducing input signal dynamic range in accordance with an attenuation control signal, thereby generating an output signal on a signal output of the multichannel equalizer.

13. A method according to claim 12, wherein reducing further comprises reducing input signal dynamic range to be no greater than a predetermined dynamic range.

14. A method according to claim 13, further comprising digitizing the output signal with an analog to digital (A/D) converter, and wherein reducing further comprises reducing input signal dynamic range to be no greater than a predetermined dynamic range of the A/D converter.

15. A method according to claim 12, wherein obtaining comprises obtaining a radio frequency input signal.

17. A method according to claim 12, further comprising producing the input signal by first downconverting and first bandpass filtering a received signal.

18. A method according to claim 17, further comprising preparing the output signal for digitization by second downconverting and second bandpass filtering the output signal.

16. A method for modifying dynamic range of an input signal, the method comprising:

obtaining an input signal with an input bandwidth spanning multiple communication channels;

coupling the input signal through a multichannel signal attenuator; and

reducing input signal dynamic range in accordance with an attenuation control signal, thereby generating an output signal on a signal output of the multichannel equalizer;

wherein obtaining comprises obtaining a radio frequency input signal with an input bandwidth spanning multiple wireless communication channels.

19. A method for modifying dynamic range of an input signal, the method comprising:

obtaining an input signal with an input bandwidth spanning multiple communication channels;

coupling the input signal through a multichannel signal attenuator; and

reducing input signal dynamic range in accordance with an attenuation control signal, thereby generating an output signal on a signal output of the multichannel equalizer;

wherein reducing further comprises reducing input signal dynamic range to be no greater than a predetermined dynamic range;

wherein coupling comprises coupling the input signal through a reactive power summer.

20. A method for modifying dynamic range of an input signal, the method comprising:

obtaining an input signal with an input bandwidth spanning multiple communication channels;

coupling the input signal through a multichannel signal attenuator; and

reducing input signal dynamic range in accordance with an attenuation control signal, thereby generating an output signal on a signal output of the multichannel equalizer;

wherein reducing further comprises reducing input signal dynamic range to be no greater than a predetermined dynamic range;

wherein reducing comprises reducing input signal dynamic range in accordance with scaled signal information from a prior input signal.

21. A multichannel receiver comprising:

a multichannel signal input for carrying an input signal with an input bandwidth spanning multiple communication channels;

a multichannel signal attenuator connected to the multichannel signal input, the multichannel signal attenuator comprising a signal output and a signal attenuation input responsive to an attenuation control signal;

whereby the multichannel signal attenuator provides on the signal output an output signal corresponding to the input signal reduced in dynamic range in accordance with the attenuation control signal; and

a channelizer coupled to the analog to digital converter and comprising a plurality of recovered-channel outputs.

22. The multichannel receiver of claim 21, further comprising a multiplexer coupled to the recovered-channel outputs for providing a summed channel cancellation output signal.

23. The multichannel receiver of claim 22, further comprising a digital to analog converter coupled between the multiplexer and the signal attenuation input.

27. The multichannel receiver of claim 22, wherein the multiplexer comprises an amplitude modification circuit.

28. The multichannel receiver of claim 22, wherein the multiplexer comprises a frequency translation circuit.

29. The multichannel receiver of claim 22, wherein the multiplexer comprises a signal summation circuit.

24. A multichannel receiver comprising:

a multichannel signal input for carrying an input signal with an input bandwidth spanning multiple communication channels;

a multichannel signal attenuator connected to the multichannel signal input, the multichannel signal attenuator comprising a signal output and a signal attenuation input responsive to an attenuation control signal;

whereby the multichannel signal attenuator provides on the signal output an output signal corresponding to the input signal reduced in dynamic range in accordance with the attenuation control signal; and

a channelizer coupled to the analog to digital converter and comprising a plurality of recovered-channel outputs;

further comprising a multiplexer coupled to the recovered-channel outputs for providing a summed channel cancellation output signal;

wherein the summed channel cancellation output signal comprises recovered-channel signal data from at least one recovered-channel signal with an output level exceeding a predetermined threshold.

25. The multichannel receiver of claim 24, wherein the output level is average power in the recovered-channel signal.

26. A multichannel receiver comprising:

a multichannel signal input for carrying an input signal with an input bandwidth spanning multiple communication channels;

a multichannel signal attenuator connected to the multichannel signal input, the multichannel signal attenuator comprising a signal output and a signal attenuation input responsive to an attenuation control signal;

whereby the multichannel signal attenuator provides on the signal output an output signal corresponding to the input signal reduced in dynamic range in accordance with the attenuation control signal; and

a channelizer coupled to the analog to digital converter and comprising a plurality of recovered-channel outputs;

further comprising a multiplexer coupled to the recovered-channel outputs for providing a summed channel cancellation output signal;

wherein the summed channel cancellation output signal comprises recovered-channel signal data from at least two recovered-channel signals, each with an output level exceeding a predetermined threshold.