Method and system for down-converting an electromagnetic signal, and transforms for same, and aperture relationships

US 9,118,528 B2
Filed: 02/04/2014
Issued: 08/25/2015
Est. Priority Date: 10/21/1998
Status: Expired due to Fees

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1. A system for frequency down-converting a modulated carrier signal to a baseband signal, comprising:

a first switch coupled to a first control signal which comprises a sampling aperture with a specified frequency, wherein the first switch is on and a portion of energy that is distinguishable from noise is transferred from the modulated carrier signal as an output of said first switch during the sampling aperture of the first control signal;

a first energy storage element that stores the transferred energy from the modulated carrier signal and outputs a down-converted in-phase baseband signal portion of said modulated carrier signal;

a second switch coupled to a second control signal which comprises a sampling aperture with a specified frequency, wherein the second switch is on and a portion of energy that is distinguishable from noise is transferred from the modulated carrier signal as an output of said second switch during the sampling aperture of the second control signal;

a second energy storage element that stores the transferred energy from the modulated carrier signal and outputs a down-converted inverted in-phase baseband signal portion of said modulated carrier signal;

wherein the portions of transferred energy from each of the first and second switch are integrated over time to accumulate said portions of transferred energy from which said down-converted in-phase baseband signal portion and said down-converted inverted in-phase baseband signal portion are derived; and

a first differential amplifier circuit that combines said down-converted in-phase baseband signal portion with said down-converted inverted in-phase baseband signal portion and outputs a first channel down-converted differential in-phase baseband signal.

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Abstract

Methods, systems, and apparatuses, and combinations and sub-combinations thereof, for down-converting an electromagnetic (EM) signal are described herein. Briefly stated, in embodiments the invention operates by receiving an EM signal and recursively operating on approximate half cycles (½, 1½, 2½, etc) of the carrier signal. The recursive operations can be performed at a sub-harmonic rate of the carrier signal. The invention accumulates the results of the recursive operations and uses the accumulated results to form a down-converted signal. In an embodiment, the EM signal is down-converted to an intermediate frequency (IF) signal. In another embodiment, the EM signal is down-converted to a baseband information signal. In another embodiment, the EM signal is a frequency modulated (FM) signal, which is down-converted to a non-FM signal, such as a phase modulated (PM) signal or an amplitude modulated (AM) signal.

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36 Claims

1. A system for frequency down-converting a modulated carrier signal to a baseband signal, comprising:
- a first switch coupled to a first control signal which comprises a sampling aperture with a specified frequency, wherein the first switch is on and a portion of energy that is distinguishable from noise is transferred from the modulated carrier signal as an output of said first switch during the sampling aperture of the first control signal;
  
  a first energy storage element that stores the transferred energy from the modulated carrier signal and outputs a down-converted in-phase baseband signal portion of said modulated carrier signal;
  
  a second switch coupled to a second control signal which comprises a sampling aperture with a specified frequency, wherein the second switch is on and a portion of energy that is distinguishable from noise is transferred from the modulated carrier signal as an output of said second switch during the sampling aperture of the second control signal;
  
  a second energy storage element that stores the transferred energy from the modulated carrier signal and outputs a down-converted inverted in-phase baseband signal portion of said modulated carrier signal;
  
  wherein the portions of transferred energy from each of the first and second switch are integrated over time to accumulate said portions of transferred energy from which said down-converted in-phase baseband signal portion and said down-converted inverted in-phase baseband signal portion are derived; and
  
  a first differential amplifier circuit that combines said down-converted in-phase baseband signal portion with said down-converted inverted in-phase baseband signal portion and outputs a first channel down-converted differential in-phase baseband signal.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
- - 2. The system of claim 1, wherein said modulated carrier signal includes an amplitude variation.
  - 3. The system of claim 1, wherein said modulated carrier signal includes a phase variation.
  - 4. The system of claim 1, wherein said modulated carrier signal includes a combination of amplitude variation and phase variation.
  - 5. The system of claim 1, wherein the first switch is on for less than one-half cycle of the modulated carrier signal.
  - 6. The system of claim 1, wherein the second switch is on for approximately one-tenth of a cycle of the modulated carrier signal.
  - 7. The system of claim 1, wherein the apertures of the first and second control signals are defined by a windowing function u(t)−
    - u(t−
      
      T_A), where the length of the windowing function aperture is T_A, which is equal to an approximate half cycle of the received carrier signal, S_i(t).
  - 8. The system of claim 1, wherein the first and second control signals each control a charging and discharging cycle of their respective energy storage element by respectively controlling the first and second switching devices so that for each switching device said portion of energy that is distinguishable from noise is transferred to the respective storage element when the switch is on during the charging cycle, and a portion of the transferred energy is discharged during the discharging part of the cycle for each respective switching device when the switching device is off.
  - 9. The system of claim 8, wherein for each respective storage element, the energy discharged during any given discharge cycle is not completely discharged, with the remaining undischarged energy from the given discharge cycle becoming an initial condition for the next charging cycle.
  - 10. The system of claim 8, wherein each said control signal operates at an aliasing rate selected so that energy of the modulated carrier signal is sampled and differentially applied to the respective energy storage element at the frequency of the respective control signal'"'"'s aperture, and each respective energy storage element outputs, respectively, said differential down-converted in-phase baseband signal portion and said down-converted inverted in-phase baseband signal portion of said modulated carrier signal as a result of the alternate charging and discharging applied to the respective energy storage elements.
  - 11. The system of claim 1, wherein the frequencies of the first and second apertures have periods that are two (2) percent or greater of the modulated carrier signal'"'"'s period.
  - 12. The system of claim 1, wherein the frequencies of the first and second apertures have periods that are five (5) percent or greater of the modulated carrier signal'"'"'s period.
  - 13. The system of claim 1, wherein the frequencies of the first and second apertures have periods that are ten (10) percent or greater of the modulated carrier signal'"'"'s period.
  - 14. The system of claim 1, wherein the frequencies of the first and second apertures have periods that are twelve and a half (12.5) percent or greater of the modulated carrier signal'"'"'s period.
  - 15. The system of claim 1, further comprising:
    - a first filter that filters said down-converted in-phase baseband signal portion; and
      
      a second filter that filters said down-converted inverted in-phase baseband signal portion.
  - 16. The system of claim 15, wherein the first and second filters each comprise a low-pass filter.
  - 17. The system of claim 1, wherein said portions of transferred energy from each of the first and second switch which are integrated over time to accumulate said portions of transferred energy are integrated by a separate integration module coupled to the output of each said first and second switch.
  - 18. The system of claim 1, wherein said first and second storage elements are capacitive storage circuits, and wherein said portions of transferred energy from each of the first and second switch which are integrated over time to accumulate said portions of transferred energy are integrated by the capacitive storage circuits as they accumulate charge during successive sampling apertures.
  - 19. The system of claim 1, further comprising:
    - a third switch coupled to a third control signal which comprises a sampling aperture with a specified frequency, wherein the third switch is on and a portion of energy that is distinguishable from noise is transferred from the modulated carrier signal as an output of said third switch during the sampling aperture of the third control signal;
      
      a third energy storage element that stores the transferred energy from the modulated carrier signal and outputs a down-converted quadrature-phase baseband signal portion of said modulated carrier signal;
      
      a fourth switch coupled to a fourth control signal which comprises a sampling aperture with a specified frequency, wherein the fourth switch is on and a portion of energy that is distinguishable from noise is transferred from the modulated carrier signal as an output of said fourth switch during the sampling aperture of the fourth control signal;
      
      a fourth energy storage element that stores the transferred energy from the modulated carrier signal and outputs a down-converted differential quadrature-phase baseband signal portion of said modulated carrier signal;
      
      wherein the portions of transferred energy from each of the third and fourth switch are integrated over time to accumulate said portions of transferred energy from which said down-converted quadrature-phase baseband signal portion and said down-converted differential quadrature-phase baseband signal portion are derived; and
      
      a second differential amplifier circuit that combines said down-converted quadrature-phase baseband signal portion with said down-converted differential quadrature-phase baseband signal portion and outputs a second channel down-converted differential quadrature-phase baseband signal.
  - 20. The system of claim 19, wherein said modulated carrier signal includes an amplitude variation.
  - 21. The system of claim 19, wherein said modulated carrier signal includes a phase variation.
  - 22. The system of claim 19, wherein said modulated carrier signal includes a combination of amplitude variation and phase variation.
  - 23. The system of claim 19, wherein the third switch is on for less than one-half cycle of the modulated carrier signal.
  - 24. The system of claim 19, wherein the fourth switch is on for approximately one-tenth of a cycle of the modulated carrier signal.
  - 25. The system of claim 19, wherein the apertures of the third and fourth control signals are defined by a windowing function u(t)−
    - u(t−
      
      T_A), where the length of the windowing function aperture is T_A, which is equal to an approximate half cycle of the received carrier signal, S_i(t).
  - 26. The system of claim 19, wherein the third and fourth control signals each control a charging and discharging cycle of their respective third and fourth energy storage element by respectively controlling the third and fourth switching devices so that for each third and fourth switching device a portion of energy that is distinguishable from noise is transferred to the respective third and fourth storage element when the respective switch is on during the charging cycle, and a portion of the transferred energy is discharged during the discharging part of the cycle for each respective third and fourth switching device when the respective switching device is off.
  - 27. The system of claim 26, wherein for each respective energy storage element, the energy discharged during any given discharge cycle is not completely discharged, with the remaining undischarged energy from the given discharge cycle becoming an initial condition for the next charging cycle.
  - 28. The system of claim 26, wherein each said third and fourth control signal operates at an aliasing rate selected so that energy of the modulated carrier signal is sampled and differentially applied to the respective energy storage element at the frequency of the respective third and fourth control signal'"'"'s aperture, and each respective third and fourth energy storage element generates, respectively, said differential down-converted in-phase baseband signal portion and said down-converted inverted in-phase baseband signal portion of said modulated carrier signal from the alternate charging and discharging applied to the respective energy storage elements.
  - 29. The system of claim 19, wherein the frequencies of the third and fourth apertures have periods that are two (2) percent or greater of the modulated carrier signal'"'"'s period.
  - 30. The system of claim 19, wherein the frequencies of the third and fourth apertures have periods that are five (5) percent or greater of the modulated carrier signal'"'"'s period.
  - 31. The system of claim 19, wherein the frequencies of the third and fourth apertures have periods that are ten (10) percent or greater of the modulated carrier signal'"'"'s period.
  - 32. The system of claim 19, wherein the frequencies of the third and fourth apertures have periods that are twelve and a half (12.5) percent or greater of the modulated carrier signal'"'"'s period.
  - 33. The system of claim 19, further comprising:
    - a first filter that filters said down-converted in-phase baseband signal portion;
      
      a second filter that filters said down-converted inverted in-phase baseband signal portion;
      
      a third filter that filters said down-converted quadrature-phase baseband signal portion;
      
      a fourth filter that filters said down-converted inverted quadrature-phase baseband signal portion.
  - 34. The system of claim 33, wherein the first, second, third, and fourth filters each comprise a low-pass filter.
  - 35. The system of claim 19, wherein said portions of transferred energy from each of the first, second, third and fourth switch which are integrated over time to accumulate said portions of transferred energy are integrated by a separate integration module coupled to the output of each said first, second, third and fourth switch respectively.
  - 36. The system of claim 19, wherein said first, second, third and fourth storage elements are capacitive storage circuits, and wherein said portions of transferred energy from each of the first, second, third and fourth switch which are integrated over time to accumulate said portions of transferred energy are integrated by the capacitive storage circuits of the respective first, second, third and fourth storage elements as they accumulate charge during successive sampling apertures.

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Current Assignee
ParkerVision, Inc.
Original Assignee
ParkerVision, Inc.
Inventors
Sorrells, David F., Bultman, Michael J., Cook, Robert W., Looke, Richard C., Moses, Charley D., Rawlins, Gregory S., Rawlins, Michael W.
Primary Examiner(s)
Bhattacharya, Sam

Application Number

US14/172,392
Publication Number

US 20140241464A1
Time in Patent Office

567 Days
Field of Search

455/413, 455/113, 455/118, 455/130, 455/131, 455/182.1, 455/190.1, 455/191.1, 455/313, 455/323, 455/343, 455/350, 327/113, 375/130, 375/142, 375/143, 375/150, 375/152, 375/316, 375/343
US Class Current

1/1
CPC Class Codes

H03C 1/62   Modulators in which amplitu...

H03D 7/00   Transference of modulation ...

H03D 7/1441   using field-effect transist...

H03D 7/1475   Subharmonic mixer arrangements

H04B 1/0025   using a sampling rate lower...

H04B 1/16   Circuits

H04B 1/28   the receiver comprising at ...

H04B 7/12   Frequency diversity

H04L 25/08   Modifications for reducing ...

H04L 27/00   Modulated-carrier systems

H04L 27/06   Demodulator circuits; Recei...

H04L 27/12   Modulator circuits; Transmi...

H04L 27/14   Demodulator circuits; Recei...

H04L 27/148   using filters, including PL...

H04L 27/156   with demodulation using tem...

H04L 27/2672   Frequency domain

H04L 27/3881   using sampling and digital ...

Method and system for down-converting an electromagnetic signal, and transforms for same, and aperture relationships

First Claim

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Abstract

44 Citations

36 Claims

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Method and system for down-converting an electromagnetic signal, and transforms for same, and aperture relationships

First Claim

1 Assignment

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Litigations

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Accused Products

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Abstract

44 Citations

36 Claims

Specification

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