Wideband frequency hopping spread spectrum transceivers and related methods

• US 20090161729A1
• Filed: 10/28/2008
• Published: 06/25/2009
• Est. Priority Date: 12/19/2007
• Status: Active Grant

• Current Assignee: L-3 Communications Integrated Systems LP (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Integrated Systems LP (L3Harris Technologies, Inc.)
• Inventors: Fudge, Gerald L.
• Granted Patent: US 8,149,894 B2
• Time in Patent Office: Days
• US Class Current: 375/133
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 7/285 Receivers
• CPC Class Codes: H04B 1/7136 Arrangements for generation of hop frequencies, e.g. using a bank of frequency sources, using continuous tuning or using a transform
• CPC Class Codes: H04B 1/71635 Transmitter aspects H04B1/7174 takes precedence
• CPC Class Codes: H04B 1/71637 Receiver aspects H04B1/7183 takes precedence
• CPC Class Codes: H04B 2001/71362 using a bank of frequency sources

Abstract

Systems and methods are disclosed that provide ultra-wideband frequency hopping spread spectrum (UWB-FHSS) solutions for transceiver architectures. These UWB-FHSS transceiver architectures can transmit and accurately digitize frequency hops over an extremely wide bandwidth while using a relatively slow analog-to-digital converter (ADC) without suffering from unacceptable performance degradation. For example, ADCs can be used having sample rates lower than standard Nyquist criteria would require for the bandwidth of the spread spectrum utilized.

Claims

1. A wideband frequency hopping spread spectrum transceiver, comprising:

a wideband frequency hopping spread spectrum transmitter, comprising;

sampling circuitry configured to receive a transmit signal at an intermediate frequency (f_IF) and to receive sampling signals at a sample clock frequency (f_S) and configured to generate sampled output signals having a plurality of frequency components, the frequency components including frequencies at two or more harmonics of f_S plus and minus f_IF;

frequency select filter circuitry configured to receive the sampled output signals and to receive a frequency selection signal, the frequency select filter circuitry configured to provide a plurality of different selectable filter passband frequency ranges across a bandwidth that includes at least two harmonics of the sample clock frequency (f_S), the frequency select filter circuitry further having an output signal within a selected filter passband frequency range that includes one frequency component of the sampled output signals;

frequency hopping control circuitry configured to output the frequency selection signal and to adjust the frequency selection signal over time so that the output signal hops to different frequency components depending upon the selected filter passband frequency range; and

transmit antenna circuitry configured to transmit the output signal as it hops to different frequency components over time; and

a wideband frequency hopping spread spectrum receiver, comprising;

receive antenna circuitry configured to receive input receive signals from a wideband frequency hopping spread spectrum transmitter as it hops to different frequency components over time;

sampling circuitry configured to receive the input receive signal at a radio frequency (f_RF), to receive sampling signals at a sample clock frequency (f_S) and to generate sampled output signals having a plurality of frequency components, the frequency components including frequencies at two or more harmonics of f_S plus and minus f_RF, and the frequency components including at least one frequency component at an intermediate frequency (f_IF); and

filter circuitry configured to provide a filter passband frequency range including the intermediate frequency (f_IF), the filter circuitry further configured to receive the sampled output signals and to have an output signal that includes the frequency component of the sampled output signals at the intermediate frequency (f_IF).

2. The wideband frequency hopping spread spectrum transceiver of claim 1, wherein the frequency select filter circuitry comprises a plurality of different selectable filters, wherein each selectable filter having a passband frequency range configured to pass one frequency component of the sampled output signals, and wherein the frequency selection signal is configured to select one of the different selectable filters.

3. The wideband frequency hopping spread spectrum transceiver of claim 1, wherein the sample clock frequency for the receiver is configured to match the sample clock frequency for the transmitter.

4. The wideband frequency hopping spread spectrum transceiver of claim 3, wherein the sample clock frequency (f_S) for the receiver and transmitter is about 1 GHz or greater and the intermediate frequency (f_IF) is about 200 MHz or less.

5. The wideband frequency hopping spread spectrum transceiver of claim 1, wherein the sample clock frequency for the receiver is configured to be different from the sample clock frequency used for the transmitter.

6. The wideband frequency hopping spread spectrum transceiver of claim 5, wherein the receive sample clock frequency is different from the transmit sample clock frequency by less than ten percent.

7. The wideband frequency hopping spread spectrum transceiver of claim 6, wherein the sample clock frequency (f_S) for the transmitter is about 1 GHz or greater and the intermediate frequency (f_IF) is about 200 MHz or less.

8. The wideband frequency hopping spread spectrum transceiver of claim 5, wherein the filter circuitry within the receiver comprises a plurality of narrowband bandpass filters each having a filter passband frequency range centered on a different intermediate frequency (f_IF) and wherein output signals from each of the plurality of narrowband bandpass filters are processed to determine which one of a plurality of frequency components was used to transmit the receive signal.

9. The wideband frequency hopping spread spectrum transceiver of claim 1, wherein the receive input signals comprise return signals transmitted by the transmitter.

10. The wideband frequency hopping spread spectrum transceiver of claim 9, further comprising conversion and processing circuitry within the receiver coupled to receive and process the frequency components at the intermediate frequency (f_IF) to determine a position of an external object.

19. The method of claim 1, wherein the receive input signals comprise return signals transmitted by the transmitter.

20. The method of claim 19, further comprising converting and processing the frequency components at the intermediate frequency (f_IF) to determine a position of an external object.

11. A method for communicating wideband frequency hopping spread spectrum signals, comprising:

sampling a transmit signal at an intermediate frequency (f_IF) using sampling signals at a sample clock frequency (f_S) to generate sampled output signals having a plurality of frequency components, the frequency components including frequencies at two or more harmonics of f_Splus and minus f_IF;

selecting one of the frequency components using frequency select filter circuitry;

transmitting the selected frequency component as an output signal;

repeating the sampling, selecting and transmitting steps to select and transmit different frequency components so that the output signals hop to different frequency components over time;

receiving an input receive signal as it hops to different frequency components over time;

sampling the input receive signal using sampling signals at a sample clock frequency (f_S) to generate sampled output signals having a plurality of frequency components, the frequency components including frequencies at two or more harmonics of f_S plus and minus f_RF, and the frequency components including at least one frequency component at an intermediate frequency (f_IF); and

filtering the sampled signals with a filter passband frequency range around an intermediate frequency (f_IF) to generate an output signal that includes the frequency component of the sampled output signals at the intermediate frequency (f_IF).

12. The method of claim 11, wherein the selecting step comprises providing a plurality of selectable filters each having a passband frequency range configured to pass one frequency component of the sampled output signals and selecting one of the plurality of different selectable filters to pass one of the frequency components.

13. The method of claim 11, wherein the sampling the input receive signal step comprises using a sample clock frequency configured to match the frequency of the sample clock frequency used in the sampling a transmit signal step.

14. The method of claim 13, wherein the sampling clock frequencies are each about 1 GHz or greater and the intermediate frequency (f_IF) is about 200 MHz or less.

15. The method of claim 11, wherein the sampling the input receive signal step comprises using a sample clock frequency different from the frequency of the sample clock frequency used in the sampling a transmit signal step.

16. The method of claim 15, wherein the receive sample clock frequency is different from the transmit sample clock frequency by less than ten percent.

17. The method of claim 16, wherein the sampling clock frequencies are each about 1 GHz or greater and the intermediate frequency (f_IF) is about 200 MHz or less.

18. The method of claim 15, wherein the filtering step comprises using a plurality of narrowband bandpass filters each having a filter passband frequency range centered on a different intermediate frequency (f_IF) and further comprising processing output signals from each of the plurality of narrowband bandpass filters to determine which one of a plurality of frequency components was used to transmit the receive signal.