Spread spectrum applications of universal frequency translation

• US 7,110,435 B1
• Filed: 03/14/2000
• Issued: 09/19/2006
• Est. Priority Date: 03/15/1999
• 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., Hamilla, Joseph M., Clements, Charles D., Silver, Gregory S.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): ODOM, CURTIS B
• Application Number:
  US09/525,185
• Time in Patent Office: 2,380 Days
• Field of Search: 375130-153, 375/340, 341/143, 455/126, 455/333
• 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. A method for down-converting and de-spreading a received spread spectrum signal, comprising the steps of:

(1) receiving the spread spectrum signal having a center frequency that is above baseband; and

(2) sampling the received spread spectrum signal according to a control signal resulting in a de-spread baseband signal, wherein said control signal includes a spreading code corresponding to said received spread spectrum signal, said control signal having a center frequency that is selected so as to down-convert said received spread spectrum signal to baseband during said sampling step, wherein step (2) comprises

(a) sampling the received spread spectrum signal at a rate that is a sub-harmonic of the received spread spectrum signal, resulting in under-samples; and

(b) storing said under-samples in a storage module, wherein successive undersamples form the de-spread baseband signal.

2. The method of claim 1, wherein step (a) comprises the step of operating a switch according to said control signal.

3. The method of claim 1, wherein step (b) comprises the step of charging a capacitor with said undersamples.

4. The method of claim 1, wherein said spreading code is a PN code.

10. The method of claim 1, wherein said center frequency of said control signal is approximately equal to said center frequency of said received spread spectrum signal.

11. The method of claim 1, wherein said center frequency of said control signal is approximately a sub-harmonic of said center frequency of said received spread spectrum signal.

12. The method of claim 1, wherein said center frequency of said control signal is offset from a sub-harmonic of said center frequency of said received spread spectrum signal.

13. The method of claim 1, wherein said step (2) comprises the steps of:

(a) generating an oscillating signal having said center frequency that is determined to down-convert said received spread spectrum signal to baseband during said sampling step;

(b) generating a spreading code; and

(c) modulating said oscillating signal according to said spreading code, resulting in a spread oscillating signal.

5. A method for down-converting and de-spreading a received spread spectrum signal, comprising:

(1) receiving the spread spectrum signal; and

(2) sampling the received spread spectrum signal according to a control signal resulting in a de-spread baseband signal, wherein said control signal includes a spreading code corresponding to said received spread spectrum signal;

wherein said step (2) comprises

(a) generating an oscillating signal;

(b) generating a spreading code;

(c) modulating said oscillating signal according to said spreading code, resulting in a spread oscillating signal; and

(d) triggering a pulse generator according to said spread oscillating signal to generate said control signal.

6. An apparatus for down-converting and de-spreading a spread spectrum signal, comprising:

(1) a spreading code generator to generate a spreading-code; and

(2) a frequency down-conversion module coupled to said spreading code generator, comprising;

(a) a switch controlled by a control signal to undersample said spread spectrum signal, resulting in an undersample, wherein said control signal carries said spreading-code and has a center frequency determined so as to down-convert said spread spectrum signal to a lower frequency signal; and

(b) a storage device coupled to said switch to store said undersample, wherein successive under-samples form said de-spread baseband signal.

8. The apparatus of claim 6, wherein said storage device is one of a capacitor and an inductor.

7. An apparatus for down-converting and de-spreading a spread spectrum signal, comprising:

(1) a spreading code generator to generate a spreading-code; and

(2) a frequency down-conversion module coupled to said spreading code generator, including

(a) a switch controlled by a control signal to undersample said spread spectrum signal, resulting in an undersample, wherein said control signal carries said spreading-code; and

(b) a storage device coupled to said switch to store said undersample, wherein successive under-samples form said de-spread baseband signal; and

(3) a pulse generator coupled between said spreading code generator and said frequency down-conversion module, comprising a means for generating said control signal having a plurality of pulses based on said spreading code.

9. An apparatus for down-converting and de-spreading a spread spectrum signal, comprising:

(1) an oscillator for generating an oscillating signal;

(2) a spreading code generator for generating a spreading code;

(3) a modulator coupled to said oscillator and said spreading code generator for generating a spread oscillating signal using said oscillating signal and said spreading code;

(4) a pulse generator coupled to said modulator, for generating a control signal using said spread oscillating signal; and

(5) a frequency translation module coupled to said pulse generator, comprising;

(a) a switch controlled by said control signal to undersample said spread spectrum signal; and

(b) a storage device coupled to said switch to store undersamples from step (5a), wherein successive under-samples form a de-spread baseband signal.

14. A method for down-converting and de-spreading a received spread spectrum signal, comprising the steps of:

(1) receiving the spread spectrum signal having a center frequency that is above baseband;

(2) generating a control signal having a center frequency that is selected to down-convert said received spread spectrum signal to baseband, and said control signal also including a spreading code corresponding to said received spread spectrum signal; and

(3) under-sampling the received spread spectrum signal according to said control signal so as to down-convert and de-spread said spread spectrum signal.

15. The method of claim 14, wherein said under-sampling step includes the step of under-sampling the received spread spectrum signal according to said control signal so as to simultaneously down-convert and de-spread said spread spectrum signal.