Wideband frequency hopping spread spectrum receivers and related methods

• US 8,184,673 B2
• Filed: 10/28/2008
• Issued: 05/22/2012
• Est. Priority Date: 12/19/2007
• Status: Expired due to Fees

• 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.
• Primary Examiner(s): Torres, Juan A
• Application Number:
  US12/290,168
• Publication Number:
  US 20090161731A1
• Time in Patent Office: 1,302 Days
• Field of Search: 375/136, 375/133
• US Class Current: 375/136
• 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

Ultra-wideband frequency hopping spread spectrum (UWB-FHSS) solutions are used for receive architectures. These UWB-FHSS receive architectures can receive signals transmitted 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 receiver, comprising:

sampling circuitry configured to receive a 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 receiver of claim 1, wherein the sample clock frequency is configured to match a frequency of a transmit sample clock frequency used to generate the receive signal.

3. The wideband frequency hopping spread spectrum receiver of claim 2, wherein the filter circuitry comprises a narrowband bandpass filter having a filter passband frequency range including the intermediate frequency f_IF.

4. The wideband frequency hopping spread spectrum receiver of claim 1, wherein the sample clock frequency is configured to be different from a frequency of a transmit sample clock frequency used to generate the receive signal.

5. The wideband frequency hopping spread spectrum receiver of claim 4, wherein the receive sample clock frequency is different from the transmit sample clock frequency by less than ten percent.

6. The wideband frequency hopping spread spectrum receiver of claim 2, wherein the filter circuitry comprises a plurality of narrowband bandpass filters each having a filter passband frequency range centered on a different intermediate frequency f_IF.

7. The wideband frequency hopping spread spectrum receiver of claim 5, 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.

8. The wideband frequency hopping spread spectrum receiver of claim 1, further comprising amplifier circuitry configured to receive the receive signal from an antenna and to provide an amplified receive signal to the sampling circuitry.

9. The wideband frequency hopping spread spectrum receiver of claim 1, wherein the filter circuitry comprises a narrowband interpolation filter centered around f_IF.

10. The wideband frequency hopping spread spectrum receiver of claim 1, wherein the sample clock frequency f_S is about 1 GHz or greater and the intermediate frequency f_IF is about 200 MHz or less.

11. The wideband frequency hopping spread spectrum receiver of claim 1, wherein the sampling signals comprise modulated sampling clock signals.

12. The wideband frequency hopping spread spectrum receiver of claim 1, wherein the sampling clock signal comprises a tuned sampling clock signal.

13. The wideband frequency hopping spread spectrum receiver of claim 1, further comprising mixer circuitry configured to receive the filtered signals from the narrowband filter circuitry and to output an analog baseband signal, an analog-to-digital converter (ADC) configured to receive the analog baseband signal and output a digital signal, and digital signal processor (DSP) circuitry configured to receive and process the digital signal.

14. A method for receiving wideband frequency hopping spread spectrum signals, comprising:

sampling a receive signal, received at a frequency f_RF, 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.

15. The method of claim 14, wherein the sampling step comprises using a sample clock frequency configured to match a frequency of a transmit sample clock frequency used to generate the receive signal.

16. The method of claim 15, wherein the filtering step comprises using a narrowband bandpass filter having a filter passband frequency range including the intermediate frequency f_IF.

17. The method of claim 14, wherein the sampling step comprises using a sample clock frequency configured to be different from a frequency of a transmit sample clock frequency used to generate the receive signal.

18. The method of claim 17, wherein the receive sample clock frequency is different from the transmit sample clock frequency by less than ten percent.

19. The method of claim 17, 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.

20. The method of claim 19, 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.

21. The method of claim 14, wherein the sampling step comprises using a sample clock frequency f_S of about 1 GHz or greater and an intermediate frequency f_IF of about 200 MHz or less.