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

• US 7,724,845 B2
• Filed: 03/28/2006
• Issued: 05/25/2010
• Est. Priority Date: 04/16/1999
• Status: Expired due to Fees

• Current Assignee: ParkerVision, Inc.
• Original Assignee: ParkerVision, Inc.
• Inventors: Cook, Robert W., Rawlins, Gregory S., Bultman, Michael J., Sorrells, David F., Moses, Charley D. Jr., Looke, Richard C., Rawlins, Michael W.
• Primary Examiner(s): Odom; Curtis B
• Application Number:
  US11/390,153
• Publication Number:
  US 20060198474A1
• Time in Patent Office: 1,519 Days
• Field of Search: 375/324, 375/343
• US Class Current: 375/343
• 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

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.

Claims

1. A method for down-converting an electromagnetic signal, comprising the steps of:

(1) performing with a finite time integrating module a finite time integrating operation on a portion of a carrier signal;

(2) accumulating the result of the finite time integrating operation of step (1); and

(3) repeating steps (1) and (2) for additional portions of the carrier signal, whereby the accumulation results form a down-converted signal.

2. The method according to claim 1, wherein step (1) comprises the step of operating on an approximate half cycle of the carrier signal with a filter having an approximately rectangular impulse response and integrating the output of the filter.

3. The method according to claim 1, wherein step (1) comprises the step of controlling a switch to pass an approximate half cycle of the carrier signal through the switch and integrating the output of the switch.

4. The method according to claim 1, where D₁ is a transform, u(t) is a step function, u(t)−

u(t−

T_A) is a windowing operator or aperture of duration T_A, and A sin (φ

t N) is an approximate half cycle of the carrier signal, and wherein step (1) comprises the step of processing the approximate half cycle of the carrier signal in accordance with;

D₁=∫

₀^TA(u(t)−

u(t−

T_A))·

A sin(ω

t φ

)dt.

5. The method according to claim 1, wherein step (2) comprises the step of transferring a portion of the energy contained in an approximate half cycle of the carrier signal to an energy storage device.

6. The method according to claim 1, wherein step (2) comprises the step of transferring a portion of the energy contained in an approximate half cycle of the carrier signal to a capacitive storage device.

7. The method according to claim 1, where E is energy, A is a constant, S_i(t) is the carrier signal, A·

S_i(t) is an aperture impulse response of duration T_A, and wherein step (2) comprises the step of accumulating energy from an approximate half cycle of the carrier signal in accordance with;

$E={\left({\int <br><br>}_0^{T_A}<br><br>A·<br><br>S_i<br><br>\left(t\right)\right)}^2<br><br><br><br>d<br><br>t.$

8. The method according to claim 1, further comprising the step of:

(4) passing on the accumulation result of step (2) to a reconstruction filter.

9. The method according to claim 1, further comprising the step of:

(4) passing on the accumulation result of step (2) to an interpolation fiter.

10. The method according to claim 1, wherein step (3) comprises the step of repeating steps (1) and (2) at a sub-harmonic rate of the carrier signal.

11. The method according to claim 1, wherein step (3) comprises the step of repeating steps (1) and (2) at an off-set of a sub-harmonic rate of the carrier signal.

12. The method according to claim 1, further comprising the step of:

(4) performing steps (1), (2), and (3) for positive approximate half cycles of the carrier signal and for inverted negative approximate half cycles of the carrier signal.

13. A system for down-converting an electromagnetic signal, comprising:

a first finite time integrating module that receives an input signal, wherein said first finite time integrating module down-converts said input signal according to a first control signal and outputs a down-converted in-phase signal portion of said input signal;

a second finite time integrating module that receives said input signal, wherein said second finite time integrating module down-converts said input signal according to a second control signal and outputs a down-converted inverted in-phase signal portion of said input signal, wherein said down-converted inverted in-phase signal portion is substantially equal to an inverted version of said down-converted in-phase signal portion of said input signal; and

a first combiner module that combines said down-converted inverted in-phase signal portion with said down-converted in-phase signal portion and outputs a first channel down-converted signal;

wherein a second control signal pulse of said second control signal occurs 1.5 cycles of a frequency of said input signal after the occurrence of a first control signal pulse of said first control signal.

14. The system of claim 13, wherein said input signal is a RF carrier signal that is AM, FM, or PM modulated with an information signal.

15. The system of claim 14, wherein said first channel down-converted signal is a baseband signal.

16. The system of claim 14, wherein said first channel down-converted signal is an intermediate frequency signal.

17. The system of claim 13, further comprising:

a third finite time integrating module that receives said input signal, wherein said third finite time integrating module down-converts said input signal according to a third control signal and outputs a down-converted quadrature-phase signal portion of said input signal;

a fourth finite time integrating module that receives said input signal, wherein said fourth finite time integrating module down-converts said input signal according to a fourth control signal and outputs a down-converted inverted quadrature-phase signal portion of said input signal; and

a second combiner module that combines said down-converted inverted quadrature-phase signal portion with said down-converted quadrature-phase signal portion and outputs a second channel down-converted signal.

18. The system of claim 17, wherein said first combiner module and said second combiner module each comprise a differential amplifier.

19. The system of claim 17, 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; and

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

20. The system of claim 19, wherein said first, second, third, and fourth filters each comprise a low-pass filter.

21. The system of claim 20, wherein each said low-pass filter comprises a resistor and a capacitor.

22. The system of claim 17, further comprising a low-noise amplifier that amplifies said input signal.

23. The system of claim 17, wherein said input signal comprises an RF I/Q modulated signal.

24. The system of claim 23, wherein said first channel down-converted signal comprises an I-phase information signal portion of said RF I/Q modulated signal, and wherein said second channel down-converted signal comprises a Q-phase information signal portion of said RF I/Q modulated signal.

25. The system of claim 24,

wherein a fourth control signal pulse of said fourth control signal occurs 1.5 cycles of said frequency of said input signal after the occurrence of a third control signal pulse of said third control signal;

and

wherein said third control signal pulse occurs 0.75 cycles of said frequency of said input signal after the occurrence of said first control signal pulse.