Ultra low power RF link
View Patent ↗A receiver including a processor. A plurality of Fast Fourier Transforms of a plurality of signal segments of a signal can be determined by the processor. The plurality of Fast Fourier Transforms are stored. A frequency shift of the signal can be determined recursively based on the stored plurality of Fast Fourier Transforms of the plurality of signal segments.
1. A receiver comprising:
a processor configured to:
determine a plurality of Fast Fourier Transforms of a plurality of signal segments of a signal;
store the plurality of Fast Fourier Transforms; and
determine, recursively, a frequency shift of the signal based on the stored plurality of Fast Fourier Transforms of the plurality of signal segments.
2. The receiver of claim 1 , further comprising a first surface acoustic wave (SAW) filter configured to pass a first band of frequencies, wherein the first band of frequencies include a frequency of the signal.
3. The receiver of claim 2 , further comprising a second SAW filter configured to pass a second band of frequencies, wherein the second band of frequencies include the frequency of the signal.
4. The receiver of claim 3 , wherein the processor is further configured to adjust a first center frequency of the first SAW filter and a second center frequency of the second SAW filter based on the determined frequency shift.
5. The receiver of claim 1 , further comprising an analog to digital converter configured to digitize the signal for input to the processor.
6. The receiver of claim 1 , wherein the frequency shift of the signal is determined by:
calculating an energy of each of a plurality of frequency paths, wherein each of the plurality of frequency paths includes at least one of the stored plurality of Fast Fourier Transforms of the plurality of signal segments; and
selecting a frequency path of the plurality of paths with the greatest energy.
7. The receiver of claim 1 , wherein the signal comprises data from at least one of a sensor, a speech converter, and a network monitor.
8. The receiver of claim 1 , wherein the signal has a data rate less than or equal to 200 bits per second.
9. An article of manufacture including a tangible computer-readable medium having instructions stored thereon that, if executed by a computing device, cause the computing device to perform operations comprising:
determining a plurality of Fast Fourier Transforms of a plurality of signal segments of a signal;
storing the plurality of Fast Fourier Transforms; and
determining, recursively, a frequency shift of the signal based on the stored plurality of Fast Fourier Transforms of the plurality of signal segments.
10. The article of manufacture of claim 9 , further comprising instructions to adjust a center frequency of a SAW filter based on the determined frequency shift, wherein the SAW filter is configured to pass a band of frequencies including a frequency of the signal.
11. The article of manufacture of claim 9 , wherein determining the frequency shift of the signal comprises:
calculating an energy of each of a plurality of frequency paths, wherein each of the plurality of frequency paths includes at least one of the stored plurality of Fast Fourier Transforms of the plurality of signal segments; and
selecting a frequency path of the plurality of frequency paths with the greatest energy.
12. The article of manufacture of claim 9 , wherein storing the plurality of Fast Fourier Transforms comprises:
storing each Fast Fourier Transform of the plurality of Fast Fourier Transforms in a frequency bin based on a frequency of each Fast Fourier Transform.
13. The article of manufacture of claim 9 , wherein the signal comprises data from at least one of a sensor, a speech converter, and a network monitor.
14. The article of manufacture of claim 9 , wherein the signal has a data rate less than or equal to 200 bits per second.
15. A method of frequency tracking comprising:
determining a plurality of Fast Fourier Transforms of a plurality of signal segments of a signal;
storing the plurality of Fast Fourier Transforms; and
determining, recursively, a frequency shift of the signal based on the stored plurality of Fast Fourier Transforms of the plurality of signal segments.
16. The method of claim 15 , further comprising adjusting a center frequency of a SAW filter based on the determined frequency shift, wherein the SAW filter is configured to pass a band of frequencies including a frequency of the signal.
17. The method of claim 15 , wherein determining the frequency shift of the signal comprises:
calculating an energy of each of a plurality of frequency paths, wherein each of the plurality of frequency paths includes at least one of the stored plurality of Fast Fourier Transforms of the plurality of signal segments; and
selecting a frequency path of the plurality of frequency paths with the greatest energy.
18. The method of claim 15 , wherein storing the plurality of Fast Fourier Transforms comprises:
storing each Fast Fourier Transform of the plurality of Fast Fourier Transforms in a frequency bin based on a frequency of each Fast Fourier Transform.
19. The method of claim 15 , wherein the signal comprises data from at least one of a sensor, a speech converter, and a network monitor.
20. The method of claim 15 , wherein the signal has a data rate less than or equal to 200 bits per second.