Determining operating characteristics of signal generator using measuring device

Patent metadata

Field	Value
Publication number	US-9632122-B2
Application number	US-201414312417-A
Country	US
Kind code	B2
Filing date	Jun 23, 2014
Priority date	Jun 23, 2014
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A method determines operating characteristics of a signal generator. The method includes performing a first set of measurements of an output signal generated by the signal generator and corresponding reflected signal, where the first set of measurements is performed over multiple frequencies and amplitudes of the output signal; applying an external signal to the output port of the signal generator; performing a second set of measurements of the output signal and corresponding reflected signal while the external signal is being applied to the output port, where the second set of measurements is performed over frequencies and amplitudes of the output signal, the external signal having the same frequency as the output signal for each measurement of the second set of measurements. A set of coefficients describing the operating characteristics of the signal generator is determined by processing results of the first and second sets of measurements through a non-linear model.

First claim

What is claimed is:

1. A method of determining operating characteristics of a signal generator by a measuring device, the method comprising:
performing a first set of measurements of an output signal generated by the signal generator and a corresponding reflected signal at an output port of the signal generator, while no external signal is being applied to the output port, wherein the first set of measurements is performed over a plurality of frequencies and a plurality of amplitudes of the output signal;
applying an external signal to the output port of the signal generator;
performing a second set of measurements of the output signal and the corresponding reflected signal at the output port of the signal generator while the external signal is being applied to the output port, wherein the second set of measurements is performed over the plurality of frequencies and the plurality of amplitudes of the output signal, the external signal having the same frequency as the output signal for each measurement of the second set of measurements; and
determining a set of coefficients describing the operating characteristics of the signal generator by processing results of the first and second sets of measurements through a non-linear model.

2. The method of claim 1 , wherein the external signal applied to the output port of the signal generator is set to an expected maximum amplitude of the plurality of amplitudes of the output signal less a predetermined constant ensuring a linearity constraint for small signal response is not violated.

3. The method of claim 1 , wherein the second set of measurements is performed over a plurality of phase states of the external signal relative to a phase of the output signal for each frequency.

4. The method of claim 3 , wherein the phase state of the external signal is rotated over 360 degrees in relation to the phase of the output signal.

5. The method of claim 4 , wherein the second set of measurements comprises measurements of the output signal while applying the external signal to the output port at phases of 90 degrees, 180 degrees, 270 degrees and 360 degrees for each frequency.

6. The method of claim 1 , wherein the measuring device comprises a vector network analyzer (VNA) comprising a test port, a tuned receiver and an internal signal source.

7. The method of claim 6 , wherein the first and second sets of measurements are performed by the tuned receiver configured to receive the output signal generator by the signal generator via the test port, and the external signal applied to the output port of the signal generator is generated by the signal source of the VNA.

8. The method of claim 7 , further comprising:
reference signal locking the signal source of the VNA and the signal generator for performing the first and second sets of measurements.

9. The method of claim 1 , wherein the set of coefficients is valid for a specific large signal operating point of the output signal, the large signal operating point being set by the signal generator.

10. The method of claim 9 , wherein the set of coefficients describe complete non-linear input and output signal mapping.

11. The method of claim 9 , wherein the set of coefficients comprises:
a first coefficient that describes simpler non-linear input and output signal mapping; and
a set of two coefficients that describes linearized input and output signal mapping, wherein the set of two coefficients comprises:
a second coefficient for linearized mapping of the input signal to the output signal, and
a third coefficient for linearized mapping of a conjugated input signal to the output signal.

12. The method of claim 11 , wherein the non-linear model comprises the output signal at the output port of the signal generator being equal to the first coefficient, plus the product of the second coefficient and the reflected signal corresponding to the output signal at the output port, plus the product of the third coefficient, the conjugate of the reflected signal corresponding to the output signal at the output port, and the square of the phase of the output signal resulting from phase normalization.

13. A measuring device for determining operating characteristics of a device under test (DUT), the device comprising:
a test port configured to connect to an output port of the DUT for inputting an output signal generated by the DUT and output at the output port, and for outputting a reflected signal corresponding to the output signal;
a signal source configured to generate an external signal selectively applied to the output port of the DUT;
a first receiver configured to perform a first set of output signal measurements of the output signal generated by the DUT via a first coupler with no external signal applied to the output port of the DUT, and configured to perform a second set of output signal measurements of the output signal via the first coupler with the external signal applied to the output port of the DUT;
a second receiver configured to perform a first set of reflected signal measurements of the reflected signal via a second coupler with no external signal applied to the output port of the DUT, and configured to perform a second set of reflected signal measurements of the reflected signal via the second coupler with the external signal applied to the output port of the DUT;
a processing unit configured to determine a set of coefficients describing the operating characteristics of the DUT by processing results of the first and second sets of output signal measurements and reflected signal measurements through a non-linear model,
wherein the first and second sets of output signal measurements and reflected signal measurements are performed over a plurality of frequencies and a plurality of amplitudes of the output signal, the external signal having the same frequency as the output signal for each measurement of the second sets of output signal and reflected signal measurements.

14. The device of claim 13 , wherein the first and second receivers perform the second set of output signal measurements and reflected signal measurements, respectively, over a plurality of phase states of the external signal relative to a phase of the output signal for each frequency during the first set of output signal measurements.

15. The device of claim 14 , wherein the phase state of the external signal is rotated over 360 degrees in relation to the phase of the output signal during the first set of output signal measurements.

16. The device of claim 15 , wherein the first receiver performs the second set of output signal measurements while the signal source applies the external signal at phases of 90 degrees, 180 degrees, 270 degrees and 360 degrees for each frequency.

17. The device of claim 13 , wherein the set of coefficients comprises:
a first coefficient that describes simpler non-linear input and output signal mapping; and
a set of two coefficients that describes linearized input and output signal mapping, wherein the set of two coefficients comprises:
a second coefficient for linearized mapping of the input signal to the output signal, and
a third coefficient for linearized mapping of a conjugated input signal to the output signal.

18. The device of claim 17 , wherein the non-linear model comprises the output signal at the output port of the DUT being equal to the first coefficient, plus the product of the second coefficient and the reflected signal corresponding to the output signal at the output port, plus the product of the third coefficient, the conjugate of the reflected signal

Assignees

• Keysight Technologies Inc

Inventors

• Betts Loren C
• Blackham David V
• Dobbert Michael C
• Li Xiaolong
• Sariaslani Dara
• Shenton Lisa
• Siegel Erwin F
• Smith Bernadette
• Todhunter Matt
• Wong Kenneth H

Classifications

• G01R31/2822

  of microwave or radiofrequency circuits (of attenuation, gain, e.g. using network analyzers G01R27/28) · CPC title

• G01R27/06 Primary

  Measuring reflection coefficients; Measuring standing-wave ratio · CPC title

• G01R27/32

  in circuits having distributed constants {, e.g. having very long conductors or involving high frequencies} · CPC title