Non-intrusive passive intermodulation testing

Patent metadata

Field	Value
Publication number	US-9291652-B2
Application number	US-201213588224-A
Country	US
Kind code	B2
Filing date	Aug 17, 2012
Priority date	Aug 17, 2012
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

A passive intermodulation test device includes a first signal generator that generates a first signal and a second signal generator that generates a second signal. A combiner combines the first signal and the second signal to generate a combined signal. A duplexer receives a test signal based, at least in part, on the combined signal and filters the first signal and the second signal from the test signal to generate an intermodulation signal. A variable low-noise amplifier amplifies the intermodulation signal in accordance with a variable gain based at least in part on a selected power level. A receiver, upon receipt of the intermodulation signal, measures intermodulation generated by a device under test.

First claim

The invention claimed is:

1. A passive intermodulation test device comprising:
a first signal generator configured to generate a first signal;
a second signal generator configured to generate a second signal;
a first combiner configured to combine the first signal and the second signal to generate a combined signal, and to provide the combined signal directly to an unduplexed device under test;
a second combiner configured to combine the first signal and the second signal to generate a combined signal;
a first duplexer configured to receive a test signal from the unduplexed device under test based at least in part on the combined signal from the first combiner, and wherein the first duplexer is configured to filter the first signal and the second signal from the test signal to generate an intermodulation signal;
a second duplexer configured to receive the combined signal from the second combiner, and to transmit the combined signal to a duplexed device under test;
a variable low-noise amplifier in communication with the first duplexer and configured to amplify the intermodulation signal in accordance with a variable gain based at least in part on a selected power level; and
a receiver in communication with the variable low-noise amplifier and configured to receive the intermodulation signal and measure intermodulation generated by the unduplexed device under test.

2. A device as set forth in claim 1 , wherein the first signal generator is configured to generate the first signal having a first frequency, the second signal generator is configured to generate the second signal having a second frequency, and the first frequency is different from the second frequency.

3. A device as set forth in claim 1 , further comprising a plurality of power amplifiers, wherein a first power amplifier is configured to amplify the first signal to a first power level and a second power amplifier is configured to amplify the second signal to a second power level.

4. A device as set forth in claim 3 , wherein the first power level is different from the second power level.

5. A device as set forth in claim 1 , further comprising:
a transmit port configured to interface with the unduplexed device under test, and wherein the first combiner is configured to output the combined signal to the unduplexed device under test via the transmit port; and
a receive port configured to interface with the unduplexed device under test, and wherein the first duplexer is configured to receive the test signal from the unduplexed device under test via the receive port.

6. A device as set forth in claim 1 , wherein the variable low-noise amplifier is configured to adjust the variable gain based at least in part on a sensitivity of the receiver.

7. A device as set forth in claim 1 , further comprising a transmit/receive port configured to interface with the duplexed device under test.

8. A device as set forth in claim 7 , further comprising a low-noise amplifier configured to receive signals from the duplexed device under test via the second duplexer.

9. A method comprising:
generating a first signal;
generating the second signal;
combining, by a first combiner, the first signal with the second signal to produce a combined signal;
transmitting the combined signal from the first combiner directly to an unduplexed device under test;
receiving, by a first duplexer, a test signal from the unduplexed device under test, wherein the test signal is based at least in part on the first signal and the second signal;
filtering the test signal to generate an intermodulation signal;
determining a sensitivity of a receiver;
adjusting a variable gain of a variable low-noise amplifier based at least in part on the sensitivity of the receiver;
measuring intermodulation generated by the unduplexed device under test based at least in part on the intermodulation signal;
combining, by a second combiner, the first signal and the second signal to produce a combined signal; and
transmitting the combined signal from the second combiner to a duplexed device under test via a second duplexer.

10. A method as set forth in claim 9 , further comprising:
receiving a selection of a first power level, wherein generating the first signal is based at least in part on the first power level; and
receiving a selection of a second power level, wherein generating the second signal is based at least in part on the second power level.

11. A method as set forth in claim 9 , wherein filtering the test signal includes filtering the first signal and the second signal from the test signal.

12. A method as set forth in claim 9 , further comprising displaying the measured intermodulation on a display device.

13. A method as set forth in claim 9 , further comprising receiving a selection of at least one of a first frequency and a second frequency.

14. A method as set forth in claim 13 , wherein generating the first signal is based at least in part on the first frequency and wherein generating the second signal is based at least in part on the second frequency.

15. A method as set forth in claim 9 , further comprising performing a return loss pre-test prior to measuring the intermodulation generated by the unduplexed device under test.

16. A method as set forth in claim 9 , further comprising prompting a user to select at least one of a non-intrusive test and an intrusive test.

17. A non-transitory computer-readable medium tangibly embodying computer-executable instructions that when executed by a processor cause the processor to perform functions, the functions comprising:
transmitting a combined signal from a first combiner directly to an unduplexed device under test;
receiving, by a first duplexer, a test signal from the unduplexed device under test;
generating an intermodulation signal from the test signal received from the unduplexed device under test;
filtering the test signal to generate an intermodulation signal;
amplifying the intermodulation signal in accordance with a variable gain based at least in part on a selected power level;
measuring intermodulation generated by the device under test based at least in part on the intermodulation signal as amplified; and
transmitting a combined signal from a second combiner to a duplexed device under test via a second duplexer.

18. A non-transitory computer-readable medium as set forth in claim 17 , further comprising generating the combined signal by combining a first signal having a first frequency and a first power level with a second signal having a second frequency and a second power level.

19. A non-transitory computer-readable medium as set forth in claim 18 , wherein the first frequency is different from the second frequency and wherein the first power level is different from the second power level.

20. A non-transitory computer-readable medium as set forth in claim 17 , further comprising adjusting the variable gain based at least in part on a sensitivity of a receiver.

21. A non-transitory computer-readable medium as set forth in claim 17 , further comprising receiving a selection of at least one of an intrusive test and a non-intrusive test.

Assignees

• Cordaro Nicholas James
• Cellco Partnership Dba Verizon

Inventors

• Cordaro Nicholas James

Classifications

• G01R23/20 Primary

  Measurement of non-linear distortion · CPC title