Spread spectrum applications of universal frequency translation
First Claim
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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.
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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.
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Citations
15 Claims
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1. A method for down-converting and de-spreading a received spread spectrum signal, comprising the steps of:
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(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. - View Dependent Claims (2, 3, 4, 10, 11, 12, 13)
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5. A method for down-converting and de-spreading a received spread spectrum signal, comprising:
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(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.
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6. An apparatus for down-converting and de-spreading a spread spectrum signal, comprising:
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(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. - View Dependent Claims (8)
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7. An apparatus for down-converting and de-spreading a spread spectrum signal, comprising:
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(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.
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9. An apparatus for down-converting and de-spreading a spread spectrum signal, comprising:
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(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.
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14. A method for down-converting and de-spreading a received spread spectrum signal, comprising the steps of:
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(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. - View Dependent Claims (15)
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Specification