Spread spectrum applications of universal frequency translation

• US 20060280231A1
• Filed: 04/17/2006
• Published: 12/14/2006
• Est. Priority Date: 03/15/1999
• Status: Active Grant

• Current Assignee: ParkerVision, Inc.
• Original Assignee: ParkerVision, Inc.
• Inventors: Bultman, Michael J., Cook, Robert W., Rawlins, Gregory S., Sorrells, David F., Moses, Charley D. Jr., Looke, Richard C., Rawlins, Michael W., Hamilla, Joseph M., Clements, Charles D., Silver, Gregory S.
• Granted Patent: US 7,599,421 B2
• Time in Patent Office: Days
• US Class Current: 375/147
• 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: H04B 1/707 using direct sequence modulation

Abstract

Frequency translation and spread spectrum applications of same are described herein. Such applications include, but are not limited to, unified down-conversion and de-spreading, unified up-conversion and spreading, RAKE receivers utilizing unified down-conversion and de-spreading, and Early/Late receivers utilizing unified down-conversion and de-spreading, and combinations and applications of same. Additionally, applications are included for limiting spectral growth during unified up-conversion and spreading of a baseband signal.

Claims

1-16. -16. (canceled)

17. A system for down-converting and de-spreading a spread spectrum signal, comprising:

first means for generating a spreading code corresponding to the spread spectrum signal;

second means for generating a control signal that comprises said spreading code; and

third means for sampling said spread spectrum signal and storing said samples, said sampling controlled at least in part by said control signal, so as to down-convert and de-spread said spread spectrum signal to obtain a de-spread baseband signal.

18. The system of claim 17, further comprising fourth means for generating an oscillating signal.

19. The system of claim 18, further comprising fifth means for modulating the oscillating signal with the spreading code to generate a spread oscillating signal.

20. The system of claim 19, further comprising sixth means for converting said spread oscillating signal into said control signal that comprises a plurality of pulses.

21. The system of claim 20, wherein a pulse width of a pulse of said control signal is non-negligible.

22. The system of claim 20, wherein a pulse width of a pulse of said control signal is negligible.

23. The system of claim 20, wherein a pulse width of a pulse of said control signal is any fraction of a center frequency of a baseband of said spread spectrum signal.

24. The system of claim 20, wherein a frequency of said control signal is based at least in part on a frequency of said spread oscillating signal.

25. The system of claim 17, wherein said control signal is a harmonic or sub-harmonic of said spread spectrum signal.

26. The system of claim 17, wherein said third means comprises a switch controlled by said control signal to under-sample the spread spectrum signal, resulting in under-samples.

27. The system of claim 26, wherein said switch is a transistor.

28. The system of claim 17, wherein said third means comprises a storage device coupled to said switch to store said samples, wherein successive samples form said de-spread baseband signal.

29. The system of claim 28, wherein said storage device integrates non-negligible amounts of energy over multiple half-cycles of said spread spectrum signal as a function of said control signal.

30. The system of claim 28, wherein said storage device is a capacitor.

31. The system of claim 17, wherein a center frequency of said control signal is approximately equal to a center frequency of said spread spectrum signal.

32. The system of claim 17, wherein a center frequency of said control signal is above a baseband frequency of said spread spectrum signal.

33. The system of claim 17, wherein sampling comprises transferring charge from said spread spectrum signal.

34. The system of claim 17, wherein the spread spectrum signal is directly down-converted and de-spread to obtain a de-spread baseband signal.

35. The system of claim 34, wherein directly down-converting said spread spectrum signal to a de-spread baseband signal eliminates use of front-end mixers, front-end radio frequency amplification circuitry and intermediate frequency conversion circuitry.

36. A method to down-convert and de-spread a spread spectrum signal, comprising:

modulating an oscillating signal with a spreading code to generate a spread oscillating signal;

converting said spread oscillating signal into a control signal that comprises a plurality of pulses; and

down-converting and de-spreading said spread spectrum signal into a de-spread baseband signal based at least in part on said control signal.

37. The method of claim 36, wherein said control signal has a center frequency determined so as to down-convert said spread spectrum signal to a lower frequency signal.

38. The method of claim 36, wherein a center frequency of said control signal is approximately equal to a center frequency of said spread spectrum signal.

39. A system to down-convert and de-spread a spread spectrum signal, comprising:

a first circuit configured to modulate an oscillating signal based on a spreading code, and to generate a control signal that comprises a plurality of pulses; and

a second circuit configured to transfer charge from said spread spectrum signal and integrate said charge over multiple cycles of said spread spectrum signal as a function of said control signal.

40. The system of claim 39, wherein a frequency of said control signal is a harmonic or sub-harmonic of said spread spectrum signal