Methods and systems for determining a received signal frequency

• US 8,131,490 B2
• Filed: 12/20/2007
• Issued: 03/06/2012
• Est. Priority Date: 12/20/2007
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Gibson, Timothy P., Hunter, Jeffrey Kent
• Primary Examiner(s): Huynh, Phuong
• Application Number:
  US11/961,653
• Publication Number:
  US 20090164160A1
• Time in Patent Office: 1,538 Days
• Field of Search: 702 75- 79, 702/106, 702/107, 702121-126, 702189-195
• US Class Current: 702/75
• CPC Class Codes: G01R 23/02 Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
• CPC Class Codes: G01S 13/785 Distance Measuring Equipment [DME] systems

Abstract

A system and method for determining a received signal frequency by sampling the received signal at a rate less than twice a predefined nyquist rate. The system includes a distorting component configured to distort the received signal in a frequency dependent manner, at least one analog to digital converter configured to sample the received signal and the distorted signal at a rate less than twice a predefined nyquist rate, and a processing component configured to determine a frequency of the received signal based on the sampled received signal and the sampled distorted signal. The method includes distorting the received signal, sampling the received signal and the distorted signal at a rate less than twice a predefined nyquist rate, and determining a frequency of the received signal. In an embodiment, distorting includes at least one of distorting an amplitude or a group delay of the received signal.

Claims

1. A system for determining a received signal frequency by sampling the received signal at a rate less than twice a predefined nyquist frequency, the system comprising:

a distorting component configured to distort an amplitude of the received signal in a frequency dependent manner to generate a distorted signal;

an analog to digital converter (ADC) configured to sample the received signal and the distorted signal at a rate less than twice a predefined nyquist frequency to generate a sampled received signal and a sampled distorted signal; and

a processing component configured to determine a frequency of the received signal based on the sampled received signal and the sampled distorted signal.

2. The system of claim 1, further comprising:

a first switch for switching the received signal to a normal receive path or to an input of the distorting component at a first predefined switching rate; and

a second switch for switching either the received signal from the normal receive path or an output of the distorting component to an input of the at least one ADC at a second predefined switching rate.

3. The system of claim 1, wherein the distorting component is configured to distort the received signal such that higher frequencies are distorted to a greater extent of distortion than lower frequencies with the extent of distortion imposed in a monotonically increasing relationship to frequency.

4. The system of claim 1, wherein the distorting component is configured to distort the received signal such that lower frequencies are distorted to a greater extent of distortion than higher frequencies.

5. The system of claim 1, wherein the distorting component is configured to distort the received signal such that a first previously identified frequency band is distorted to a greater extent of distortion than a second previously identified frequency band.

6. The system of claim 5, wherein the extent of distortion is imposed on the first frequency band and the second frequency band in a non-monotonic fashion.

7. The system of claim 1, further comprising:

wherein the system is a distance measuring equipment (DME) system; and

wherein the received signal is a a received DME signal.

8. A method for determining a received signal frequency by sampling the received signal at a rate less than twice a predefined nyquist frequency, the method comprising:

distorting an amplitude of the received signal in a frequency dependent manner to generate a distorted signal;

sampling the received signal and the distorted signal at a rate less than twice a predefined nyquist frequency using at least one sampling means to generate a sampled received signal and a sampled distorted signal; and

determining, using a processor, a frequency of the received signal based on the sampled received signal and the sampled distorted signal.

9. The method of claim 8, further comprising:

switching the received signal to a normal receive path or to an input of the distorting component at a first predefined switching rate; and

switching either the received signal from the normal receive path or an output of the distorting component to an input of the at least one sampling means at a second predefined switching rate.

10. The method of claim 8, wherein the at least one sampling means includes a first sampling means configured to sample the received signal and a second sampling means configured to sample the distorted signal.

11. The method of claim 8, wherein distorting includes distorting the received signal such that higher frequencies are distorted to a greater extent of distortion than lower frequencies with the extent of distortion imposed in a monotonically increasing relationship to frequency.

12. The method of claim 8, wherein distorting includes distorting the received signal such that lower frequencies are distorted to a greater extent of distortion than higher frequencies.

13. The method of claim 8, wherein distorting includes distorting the received signal such that a first previously identified frequency band is distorted to a greater extent of distortion than a second previously identified frequency band.

14. The method of claim 13, wherein the extent of distortion is imposed on the first frequency band and the second frequency band in a non-monotonic fashion.

15. The method of claim 14, wherein distorting includes distorting signals within the first frequency band to a first approximately constant extent of distortion and to distort signals within the second frequency band to a second approximately constant extent of distortion, wherein the first extent of distortion and the second extent of distortion are not the same.