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

• US 8,660,513 B2
• Filed: 07/13/2012
• Issued: 02/25/2014
• Est. Priority Date: 10/21/1998
• Status: Expired due to Fees

• Current Assignee: ParkerVision, Inc.
• Original Assignee: ParkerVision, Inc.
• Inventors: Sorrells, David F., Bultman, Michael J., Cook, Robert W., Looke, Richard C., Moses, Charley D. Jr., Rawlins, Gregory S., Rawlins, Michael W.
• Primary Examiner(s): Bhattacharya, Sam
• Application Number:
  US13/549,213
• Publication Number:
  US 20130101064A1
• Time in Patent Office: 592 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
• US Class Current: 455/313
• CPC Class Codes: H03C 1/62 Modulators in which amplitude of carrier component in output is dependent upon strength of modulating signal, e.g. no carrier output when no modulating signal is present H03C1/28 - H03C1/34, H03C1/46, H03C1/48 take precedence
• CPC Class Codes: H03D 7/00 Transference of modulation from one carrier to another, e.g. frequency-changing H03D9/00, H03D11/00 take precedence; dielectric amplifiers, magnetic amplifiers, parametric amplifiers used as a frequency-changers H03F
• CPC Class Codes: H03D 7/1441 using field-effect transistors H03D7/145 takes precedence
• CPC Class Codes: H03D 7/1475 Subharmonic mixer arrangements
• CPC Class Codes: H04B 1/0025 using a sampling rate lower than twice the highest frequency component of the sampled signal for demodulation of angle-modulated signals H03D3/006
• CPC Class Codes: H04B 1/16 Circuits
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 7/12 Frequency diversity
• CPC Class Codes: H04L 25/08 Modifications for reducing interference; Modifications for reducing effects due to line faults ; Receiver end arrangements for detecting or overcoming line faults
• CPC Class Codes: H04L 27/00 Modulated-carrier systems
• CPC Class Codes: H04L 27/06 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/14 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/148 using filters, including PLL-type filters
• CPC Class Codes: H04L 27/156 with demodulation using temporal properties of the received signal, e.g. detecting pulse width
• CPC Class Codes: H04L 27/2672 Frequency domain
• CPC Class Codes: H04L 27/3881 using sampling and digital processing, not including digital systems which imitate heterodyne or homodyne demodulation

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 hasehand 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.

Claims

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

a first switch, a first control signal which comprises a sampling aperture with a specified frequency, and a first energy storage element that down-converts said modulated carrier signal according to said first control signal and outputs a down-converted in-phase signal portion of said modulated carrier signal;

a second switch, a second control signal which comprises a sampling aperture with a specified frequency, and a second energy storage element that down-converts said modulated carrier signal according to said second control signal and outputs a down-converted inverted in-phase signal portion of said modulated carrier signal;

the first and second control signals each controlling a charging and discharging cycle of their respective energy storage element by controlling the first and second switching devices so that for each switching device a portion of energy is transferred from the modulated carrier signal to the respective energy storage element during a charging part of the cycle and a portion of the transferred energy is discharged during a discharging part of the cycle for each respective switching device, and each said control signal operating 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 generating, respectively, said differential down-converted in-phase signal portion and said down-converted inverted in-phase signal portion of said modulated carrier signal from the alternate charging and discharging applied to the respective energy storage element differentially applied by each respective switching device using said respective first or second control signal; and

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

2. The system of claim 1, wherein said second control signal is delayed by 0.5+n cycles of said first control signal, wherein n comprises zero (0) or any integer greater than or equal to 1 after the occurrence of said first control signal.

3. The system of claim 1, wherein the frequencies of the first and second aperture signals have periods that are two (2) percent or greater of the modulated carrier period.

4. The system of claim 1, wherein the frequencies of the first and second aperture signals have periods that are five (5) percent or greater of the modulated carrier period.

5. The system of claim 1, wherein the frequencies of the first and second aperture signals have periods that are ten (10) percent or greater of the modulated carrier period.

6. The system of claim 1, wherein the frequencies of the first and second aperture signals have periods that are twelve and a half (12.5) percent or greater of the modulated carrier period.

7. The system of claim 1, further comprising:

a first filter that filters said down-converted in-phase signal portion; and

a second filter that filters said down-converted inverted in-phase signal portion.

8. The system of claim 7, wherein the first and second filters each comprise a low-pass filter.

9. The system of claim 1, further comprising:

a third switch, a third control signal which comprises a sampling aperture with a specified frequency, and a third energy storage element that down-converts said modulated carrier signal according to said third control signal and outputs a down-converted quadrature-phase signal portion of said modulated carrier signal;

a fourth switch, a fourth control signal which comprises a sampling aperture with a specified frequency, and a fourth energy storage element that down-converts said modulated carrier signal according to said fourth control signal and outputs a down-converted inverted quadrature-phase signal portion of said modulated carrier signal; and

a second differential amplifier circuit that combines said down-converted quadrature-phase signal portion with said inverted quadrature-phase signal portion and outputs a second channel down-converted differential quadrature-phase signal.

10. The system of claim 9, wherein said forth control signal is delayed by 0.5+n cycles of said third control signal, wherein n comprises zero (0) or any integer greater than or equal to 1 after the occurrence of said third control signal.

11. The system of claim 9, wherein the frequencies of the third and fourth aperture signals have periods that are two (2) percent or greater of the modulated carrier period.

12. The system of claim 9, wherein the frequencies of the third and fourth aperture signals have periods that are five (5) percent or greater of the modulated carrier period.

13. The system of claim 9, wherein the frequencies of the third and fourth aperture signals have periods that are ten (10) percent or greater of the modulated carrier period.

14. The system of claim 9, wherein the frequencies of the third and fourth aperture signals have periods that are twelve and a half (12.5) percent or greater of the modulated carrier period.

15. The system of claim 9, further comprising:

a third filter that filters said down-converted quadrature-phase signal portion; and

a fourth filter that filters said down-converted inverted quadrature-phase signal portion.

16. The system of claim 15, wherein the third and fourth filters each comprise a low-pass filter.

17. The system of claim 9, further comprising:

a first filter that filters said down-converted in-phase signal portion;

a second filter that filters said down-converted inverted in-phase signal portion;

a third filter that filters said down-converted quadrature-phase signal portion;

a fourth filter that filters said down-converted inverted quadrature-phase signal portion.

18. The system of claim 17, wherein the first, second, third, and fourth filters each comprise a low-pass filter.

19. A system for frequency down-converting a modulated carrier signal, comprising:

a first switch, a first control signal which comprises a sampling aperture with a specified frequency, and a first energy storage element that down-converts said modulated carrier signal according to said first control signal and outputs a down-converted in-phase signal portion of said modulated carrier signal;

a second switch, a second control signal which comprises a sampling aperture with a specified frequency, and a second energy storage element that down-converts said modulated carrier signal according to said second control signal and outputs a down-converted inverted in-phase signal portion of said modulated carrier signal;

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

a third switch, a third control signal which comprises a sampling aperture with a specified frequency, and a third energy storage element that down-converts said modulated carrier signal according to said third control signal and outputs a down-converted quadrature-phase signal portion of said modulated carrier signal;

a fourth switch, a fourth aperture signal, and a fourth energy storage element that down-converts said modulated carrier signal according to said fourth control signal and outputs a down-converted inverted quadrature-phase signal portion of said modulated carrier signal; and

a second differential amplifier circuit that combines said down-converted quadrature-phase signal portion with said inverted quadrature-phase signal portion and outputs a second channel down-converted differential quadrature-phase signal.

20. The system of claim 19, wherein said forth control signal is delayed by 0.5+n cycles of said third control signal, wherein n comprises zero (0) or any integer greater than or equal to 1 after the occurrence of said third control signal.

21. The system of claim 19, wherein the third and fourth aperture signal period is two (2) percent or greater of the modulated carrier period.

22. The system of claim 19, wherein the third and fourth aperture signal period is five (5) percent or greater of the modulated carrier period.

23. The system of claim 19, wherein the third and fourth aperture signal period is ten (10) percent or greater of the modulated carrier period.

24. The system of claim 19, wherein the third and fourth aperture signal period is twelve and a half (12.5) percent or greater of the modulated carrier period.

25. The system of claim 19, further comprising:

a third filter that filters said down-converted quadrature-phase signal portion; and

a fourth filter that filters said down-converted inverted quadrature-phase signal portion.

26. The system of claim 25, wherein the third and fourth filters each comprise a low-pass filter.

27. The system of claim 19, further comprising:

a first filter that filters said down-converted in-phase signal portion;

a second filter that filters said down-converted inverted in-phase signal portion;

a third filter that filters said down-converted quadrature-phase signal portion;

a fourth filter that filters said down-converted inverted quadrature-phase signal portion.

28. The system of claim 27, wherein the first, second, third, and fourth filters each comprise a low-pass filter.