Claims
- 1. A method for converting analog signals into a lower frequency digital signal, comprising the steps of:
- capturing a plurality of incoming spread spectrum signals within a predetermined spectral range;
- filtering out of said incoming signals a first plurality of analog spread spectrum signals in a plurality of predetermined bands with predetermined bandwidths;
- sampling said first plurality of analog signals with a sampling frequency f.sub.s wherein f.sub.s is chosen such that a resulting time-discrete signal comprises a second plurality of analog spread spectrum signals, being said first plurality of analog spread spectrum signals which have been aliased without self-aliasing.
- 2. The method as recited in claim 1 further comprising the steps of:
- digitizing said resulting time-discrete signal thereby defining a third plurality of digitized spread spectrum signals; and
- filtering one digitized signal out of said third plurality of digitized signals.
- 3. The method as recited in claim 1 wherein f.sub.s is chosen to be the minimum sampling frequency such that the resulting time-discrete signal comprises a second plurality of analog spread spectrum signals, being said first plurality of analog spread spectrum signals which have been aliased without substantial self-aliasing.
- 4. The method as recited in claim 1 wherein f.sub.s is chosen as the sampling frequency such that the resulting time-discrete signal comprises a second plurality of analog spread spectrum signals, being said first plurality of analog spread spectrum signals which have been aliased without substantial self-aliasing, f.sub.s further being chosen such that the harmonic frequencies of f.sub.s are outside of said predetermined bands and such that f.sub.s is higher than or equal to a minimum sampling frequency f.sub.min for each of said predetermined bandwidths, f.sub.min being defined as f.sub.min =(2*f1)/n with f1 being the lowest frequency of the predetermined band and n=floor(f1/B), with B the bandwidth of said band.
- 5. The method as recited in claim 1 wherein said incoming signals comprise GPS and GLONASS signals and wherein said predetermined bandwidths comprise at least one bandwidth covering both adjacent GPS and GLONASS frequencies.
- 6. The method as recited in claim 1 wherein f.sub.s is chosen to be the minimum sampling frequency such that said analog signals have substantially no self-aliasing.
- 7. An apparatus for receiving substantially simultaneously spread spectrum signals in different frequency ranges, comprising:
- means for capturing a plurality of incoming spread spectrum signals within a predetermined spectral range;
- a filter for filtering out of said incoming signals a first plurality of analog spread spectrum signals in a plurality of predetermined bands with predetermined bandwidths; and
- a sampling unit for sampling said analog signals with a sampling frequency f.sub.s wherein f.sub.s is chosen such that the resulting time-discrete signal comprises a second plurality of analog spread spectrum signals, being said first plurality of analog spread spectrum signals which have been aliased without self-aliasing; and
- means for digitizing said resulting time-discrete signal thereby defining a third plurality of digitized spread spectrum signals.
- 8. The apparatus as recited in claim 7 wherein said means for capturing the incoming spread spectrum signals, said filter, said sampling unit, said means for digitizing and said means for filtering are configured as a chain of electronic hardware components.
- 9. The apparatus as recited in claim 8 wherein said chain of hardware components is integrated on a single silicon chip.
- 10. A method for converting analog signals into a lower frequency digital signal, comprising the steps of:
- capturing a plurality of incoming spread spectrum signals within a predetermined spectral range;
- filtering out of said incoming signals a first plurality of analog spread spectrum signals in a plurality of predetermined bands with predetermined bandwidths;
- sampling said first plurality of analog signals with a sampling frequency f.sub.s wherein f.sub.s is chosen such that a resulting time-discrete signal comprises a second plurality of analog spread spectrum signals, being said first plurality of analog spread spectrum signals which have been aliased without self-aliasing, f.sub.s further being chosen such that the harmonic frequencies of f.sub.s are outside of said predetermined bands and such that f.sub.s is higher than or equal to a minimum sampling frequency .sup.f min for each said predetermined bandwidths, .sup.f min being defined as .sup.f min=(2*f1)/n with f1 being the lowest frequency of the predetermined band and n=floor (f1/B), with B the bandwidth of said band.
Priority Claims (1)
Number |
Date |
Country |
Kind |
97870012 |
Jan 1997 |
EPX |
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Parent Case Info
This application claims benefit of provisional application Ser. No. 60/030,449, filed Nov. 6, 1996.
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JPX |
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