Systems and methods using multiple down-conversion ratios in acquisition windows

• US 7,652,619 B1
• Filed: 05/25/2007
• Issued: 01/26/2010
• Est. Priority Date: 05/25/2007
• Status: Active Grant

• Current Assignee: Chemring Sensors and Electronic Systems Incorporated
• Original Assignee: NIITEK, Inc.
• Inventors: Hibbard, Mark, Bandell, Howard
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Bythrow; Peter M
• Application Number:
  US11/754,152
• Time in Patent Office: 977 Days
• Field of Search: 342/22, 342/175, 342/195
• US Class Current: 342/195
• CPC Class Codes: G01S 13/10 using transmission of interrupted, pulse modulated waves determination of distance by phase measurement G01S13/32
• CPC Class Codes: G01S 7/285 Receivers

Abstract

A system for processing a signal comprises a transmit unit to transmit a signal, and a receive unit receiving the signal and performing equivalent time sampling thereon by sampling each cycle of the received signal and reconstructing the received signal from the samples, wherein the receive unit applies a plurality of down-conversion rates to the equivalent time sampling for an acquisition window.

Claims

1. A system for processing a signal, the system comprising:

a transmit unit to transmit a signal; and

a receive unit receiving a reflection of the signal and performing equivalent time sampling thereon by sampling each cycle of the received signal and reconstructing the received signal from the samples, wherein the receive unit applies a plurality of down-conversion rates to the equivalent time sampling for an acquisition window.

2. The system of claim 1 further comprising:

a processor-based device receiving the reconstructed signal and applying algorithms thereto to derive information from the reconstructed signal.

3. The system of claim 2 further comprising:

a display associated with the processor-based device presenting at least some of said derived information in a humanly-perceptible form.

4. The system of claim 1 wherein said system is a radar system, and wherein said transmitted signal is a series of pulses.

5. The system of claim 1 wherein the plurality of down conversion rates comprises two different down conversion rates in the acquisition window.

6. The system of claim 1 wherein the plurality of down-conversion rates includes a continuously varying down-conversion rate.

7. The system of claim 1 wherein the receive unit equivalent time sampling provides higher resolution for neat ranges and lower resolution for far ranges in the acquisition window.

8. A method for processing a signal, the method comprising:

performing a plurality of signal transmit and receive operation pairs, wherein each subsequent receive operation is temporally spaced from its respective transmit operation by an increasing time offset to perform equivalent time sampling, the equivalent time sampling being performed with a plurality of down conversion rates for a given acquisition window.

9. The method of claim 8 wherein said time offset increases at a continuously changing rate throughout the acquisition window.

10. The method of claim 8 wherein said time offset increases at a first rate during a first part of the acquisition window and at a second rate during a second part of the acquisition window.

11. The method of claim 8 wherein said acquisition window comprises:

a period of real time over which said samples are taken.

12. The method of claim 8 wherein said method is performed by a device selected from a list consisting of:

an oscilloscope and device under test; and

a radar system.

13. The method of claim 8 further comprising:

outputting a reconstructed signal based on said receive operations in said acquisition window, the reconstructed signal representing one cycle of a received signal.

14. The method of claim 13 further comprising:

processing said reconstructed signal and displaying results of said processing.

15. The method of claim 14 wherein said results of said processing include items selected from the list consisting of:

a presence of an object determined by said processing;

a shape of an object determined by said processing;

a speed of an object determined by said processing; and

the nature of an object determined by said processing.

16. The method of claim 8 wherein said transmit and receive operations are performed by a same transceiver and antenna element.

17. A method for processing radar information, said method comprising:

transmitting a plurality of radar pulses; and

performing equivalent time sampling on returned radar pulses, wherein said equivalent time sampling provides higher resolution in a first part of an acquisition window and lower resolution in a second part of said acquisition window by applying different down conversion rates in each of said first part and said second part of said acquisition window.

18. The method of claim 17 wherein said first part of said acquisition window includes information about first objects, and wherein said second part of said acquisition window includes information about second objects, said first object being nearer to a transmitter of said radar pulses than said second objects.

19. The method of claim 17 wherein said acquisition window comprises:

an amount of real time over which samples of said transmitted signals are taken.

20. The method of claim 17 further comprising:

outputting a signal that represents a cycle of said returned radar pulses, said signal stretched over an amount of equivalent time greater than an amount of real time for one of said returned pulses.

21. The method of claim 17 further comprising digitizing a result of said equivalent time sampling.

22. The method of claim 21 further comprising:

processing said digitized result to derive information therefrom; and

displaying at least some of said derived information in a human-perceptible form.

23. The method of claim 22 wherein said derived information is selected from the list consisting of:

the presence of an object;

the shape of an object;

an object'"'"'s velocity;

the nature of an object; and

the position of an object.