METHOD AND MEASUREMENT SYSTEM FOR IDENTIFYING THE NOISE FIGURE OF A DEVICE UNDER TEST

• US 20200132754A1
• Filed: 10/25/2018
• Published: 04/30/2020
• Est. Priority Date: 10/25/2018
• Status: Active Grant

• Current Assignee: Rohde & Schwarz GmbH & Company KG
• Original Assignee: Rohde & Schwarz GmbH & Company KG
• Inventors: Lagler, Andreas, Ramian, Florian
• Granted Patent: US 10,761,134 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 29/26 Measuring noise figure; Measuring signal-to-noise ratio
• CPC Class Codes: G01R 31/2879 related to electrical aspects, e.g. to voltage or current supply or stimuli or to electrical loads
• CPC Class Codes: G01R 31/31708 Analysis of signal quality G01R31/31901 takes precedence; measuring frequencies or analysing frequency spectra per se G01R23/00; measuring non-linear distortion per se G01R23/20

Abstract

A method for identifying the noise figure of a device under test is described. A signal generator that outputs the modulated signal, a device under test and an analyzer are provided. The signal generator is connected with the analyzer directly wherein at least two error vector magnitude measurements are performed. The signal generator is connected with the device under test and the device under test is connected with the analyzer wherein at least two error vector magnitude measurements are performed. The noise contribution of the device under test is determined from the error vector magnitude measurements performed. A gain measurement is performed on the device under test. The noise figure of the device under test is calculated based on the noise contribution of the device under test obtained and the gain of the device under test obtained. Further, a measurement system is described.

Claims

1. A method for identifying the noise figure of a device under test using a modulated signal, comprising:

providing a signal generator that outputs the modulated signal, a device under test and an analyzer;

connecting the signal generator with the analyzer directly, and performing at least two error vector magnitude measurements with different average counts;

connecting the signal generator with the device under test and connecting the device under test with the analyzer directly, and performing at least two error vector magnitude measurements with different average counts;

determining the noise contribution of the device under test from the error vector magnitude measurements performed;

performing a gain measurement on the device under test; and

calculating the noise figure of the device under test based on the noise contribution of the device under test obtained and the gain of the device under test obtained.

2. The method of claim 1, wherein the noise contribution of the analyzer is measured directly.

3. The method of claim 2, wherein the noise contribution of the analyzer is measured by connecting a match with the analyzer and measuring noise power.

4. The method of claim 1, wherein the noise contribution of the signal generator and the analyzer is measured when the signal generator is connected with the analyzer directly.

5. The method of claim 1, wherein the noise contribution of the signal generator, the device under test and the analyzer is measured when the signal generator is connected with the device under test directly and the device under test is connected with the analyzer directly.

6. The method of claim 5, wherein the noise contribution of the signal generator and the analyzer obtained is compared with the noise contribution of the signal generator, the device under test and the analyzer so as to obtain the noise contribution of the device under test.

7. The method of claim 1, wherein the different average counts for the vector magnitude measurements are assigned to an average count of 1 and an average count higher than 1.

8. The method of claim 1, wherein the noise figure of the device under test is calculated only based on the contribution of the device under test obtained and the gain of the device under test obtained.

9. The method of claim 1, wherein the same signal path of the analyzer is used for the different measurements performed.

10. The method of claim 1, wherein the analyzer also receives the modulated signal provided by the signal generator as a reference signal.

17. The method of claim 4, wherein the noise contribution of the signal generator and the analyzer obtained is compared with the noise contribution of the signal generator, the device under test and the analyzer so as to obtain the noise contribution of the device under test.

11. A measurement system for identifying the noise figure of a device under test using a modulated signal, the measurement system comprising:

a signal generator that outputs the modulated signal;

a device under test; and

an analyzer,

wherein the measurement system is configured with at least two different measurement setups in which different measurements can be performed;

the signal generator is directly connected with the analyzer in a first measurement setup;

the signal generator is directly connected with the device under test as well as the device under test is directly connected with the analyzer directly in a second measurement setup;

the measurement system being configured to measure the noise contribution of the signal generator and the analyzer in the first measurement setup, and the measurement system being configured to measure the noise contribution of the signal generator, the device under test and the analyzer in the second measurement setup.

12. The measurement system of claim 11, wherein the measurement system is configured to compare the noise contribution obtained in the first measurement setup with the noise contribution obtained in the second measurement setup so as to determine the noise contribution of the device under test.

13. The measurement system of claim 11, wherein the measurement system is further configured to measure the gain of the device under test.

14. The measurement system of claim 13, wherein the measurement system is configured to calculate the noise figure of the device under test based on the noise contribution of the device under test obtained and the gain of the device under test obtained.

15. The measurement system of claim 11, wherein a match is provided that is directly connected with the analyzer in a third measurement setup, the measurement system being configured to measure the noise contribution of the analyzer in the third measurement setup.

16. The measurement system of claim 12, wherein the measurement system is configured to calculate the noise figure of the device under test based on the noise contribution of the device under test obtained and the gain of the device under test obtained.