System and method for measuring essential power amplification functions

• US 6,895,343 B2
• Filed: 07/12/2002
• Issued: 05/17/2005
• Est. Priority Date: 07/12/2002
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Upmaka, Murthy S., Jacobsen, Robert E.
• Primary Examiner(s): WACHSMAN, HAL D
• Application Number:
  US10/194,192
• Publication Number:
  US 20040010384A1
• Time in Patent Office: 1,040 Days
• Field of Search: 702/108, 702 57- 59, 702/198, 702 64- 71, 702 73- 76, 702/106, 702/107, 702/85, 702/117, 702/118, 702/124, 702/126, 702/189, 702/194, 324/638, 324/637, 324/645, 324/646, 324/650, 324/642, 324533-538, 324/601, 324/612, 324/613, 324/605, 324/76.53, 324/763, 324/765, 324/615, 324/616, 324/619, 330/84, 330/124.R, 330/126
• US Class Current: 702/57
• CPC Class Codes: G01R 27/28 Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response in line transmission systems H04B3/46

Abstract

An apparatus includes a device under test, a network analyzer, an internal amplifier, a first switch, a second switch, a third switch, a first air-line directional coupler, and a first attenuator. A method of characterization measurement includes providing a harmonics signal from the device under test to a spectrum analyzer, providing a generated signal and a reflected signal to a first receiver disposed within a network analyzer, and recording a parameter deviation of the network analyzer.

Claims

1. An apparatus for measuring signals comprising:

an amplifier coupled to a network analyzer;

a first switch coupled between the amplifier and the network analyzer;

a second switch coupled between the amplifier and the network analyzer;

a third switch coupled between a device under test and the network analyzer;

a first air-line directional coupler coupled between the second switch and the device under test; and

a first attenuator coupled to the first air-line directional coupler.

2. The apparatus of claim 1, wherein an input of the first air-line directional coupler is coupled to an output of the device under test.

3. The apparatus of claim 2, wherein:

the first attenuator is a high-power attenuator; and

the first attenuator is coupled to the main-line output of the first air-line directional coupler.

4. The apparatus of claim 2, further comprising a second air-line directional coupler coupled between the input of the first air-line directional coupler and the output of the device under test, wherein an input of the second air-line directional coupler is coupled to the output of the device under test and a main-line output of the second air-line directional coupled is coupled to the input of the first air-line directional coupler.

5. The apparatus of claim 1, wherein:

the first switch is coupled to an input of the amplifier; and

the second switch is coupled to an output of the amplifier.

6. The apparatus of claim 5, wherein the second switch is further coupled between the output of the amplifier and a coupled-line input of the first air-line directional coupler.

7. The apparatus of claim 6, further comprising a wideband isolator coupled between the second switch and the coupled-line input of the first air-line directional coupler.

8. The apparatus of claim 1, wherein the network analyzer has two ports, further comprising a fourth switch that couples the two ports together.

9. A system for measuring signals comprising:

a network analyzer;

a device under test having an input and an output;

an amplifier, having an input and an output, coupled to the network analyzer;

a first switch coupled between the input of the amplifier and the network analyzer;

a second switch coupled between the output of the amplifier and the network analyzer;

a third switch coupled between the input of the device under test and the network analyzer;

a first air-line directional coupler, having an input, a main-line output, and a coupled-line input, coupled between the second switch and the output of the device under test; and

a first attenuator coupled to the main-line output of the first air-line directional coupler, wherein the first attenuator is a high-power attenuator.

10. The system of claim 9, further comprising a signal generator coupled to the input of the device under test.

11. The system of claim 10, wherein the third switch is coupled between the signal generator and the input of the device under test.

12. The system of claim 11, further comprising a linear amplifier, having an input and an output, coupled between the signal generator and the third switch, wherein the input of the linear amplifier is coupled to the signal generator and the output of the linear amplifier is coupled to the third switch.

13. The system of claim 12, further comprising a power meter coupled to a port of the apparatus, wherein the power meter measures power entering the input of the device under test.

14. The system of claim 9, further comprising a power meter coupled to an output port of the device under test, wherein the second power meter measures the power from the output of the device under test.

15. The system of claim 14, further comprising a second air-line directional coupler, having an input, a coupled-line output, coupled between the power meter and the output port of the device under test, wherein the input of the second air-line directional coupler is coupled to the output of the device under test and the coupled-line output of the second air-line directional coupler is coupled to the power meter.

16. The system of claim 9, further comprising a spectrum analyzer coupled to an output port of the device under test.

17. The system of claim 16, wherein the first air-line directional coupler is coupled between the spectrum analyzer and the output of the device under test, wherein the input of the first air-line directional coupler is coupled to the output of the device under test and the main-line output of the first air-line directional coupler is coupled to the spectrum analyzer.

18. The system of claim 17, wherein the first attenuator is coupled between the spectrum analyzer and the main-line output of the first air-line directional coupler.

19. The system of claim 18, further comprising a second air-line directional coupler coupled between the input of the first air-line directional coupler and the output of the device under test.

20. A method for measuring signals comprising a mode that includes:

providing a first signal at a predetermined first frequency (F1) to an input of a device under test, wherein the first signal drives the device under test to full power output;

providing a second signal at a predetermined second frequency (F2) to an input of a first amplifier disposed within a measurement interface apparatus to provide an amplified second signal;

providing the amplified second signal to a wideband isolator disposed within the measurement interface apparatus to provide an isolated second signal;

passing the isolated second signal through a coupled-line of a first air-line directional coupler to a main-line of the first air-line directional coupler disposed within the measurement interface apparatus to provide a coupled second signal;

providing the coupled second signal to an output of the device under test, wherein the device under test reflects a portion of the coupled second signal as a first reflected signal (S22);

passing the first reflected signal through an input port of a main-line of a second air-line directional coupler disposed within the measurement interface apparatus to a coupled-line of the second air-line directional coupler to provide a first coupled reflected signal;

providing the first coupled reflected signal from an output port of the coupled-line of the second air-line directional coupler to a first attenuator to produce a first attenuated reflected signal; and

providing the first attenuated reflected signal to a first receiver disposed within a network analyzer coupled to the measurement interface apparatus.

21. The method of claim 20, further comprising generating the predetermined first frequency with a signal generator coupled to the measurement interface apparatus, wherein the predetermined first frequency is different from the predetermined second frequency.

22. The method of claim 20, further comprising:

providing an initial signal at the predetermined first frequency to an input of a second amplifier, wherein the initial signal is generated by a signal generator coupled to the measurement interface apparatus;

receiving an amplified version of the initial signal from an output of the second amplifier, wherein the first signal provided to the input of the device under test is the amplified version of the initial signal.

23. The method of claim 20, further comprising:

passing the amplified second signal from an output of the first amplifier through an input port of a directional coupler disposed within the measurement interface apparatus;

providing the amplified second signal from an output port of the directional coupler to the wideband isolator;

providing the amplified second signal from a coupled output port of the directional coupler to a second attenuator to produce an attenuated reference signal (R2) and

providing the attenuated reference signal to a second receiver disposed within the network analyzer.

24. The method of claim 20, further comprising an additional mode that includes:

receiving a harmonics signal at the measurement interface apparatus from the output of the device under test;

passing the harmonics signal through an input port of the main-line of the first air-line directional coupler disposed within the measurement interface apparatus; and

providing the harmonics signal from an output port of the main-line of the first air-line directional coupler to a spectrum analyzer coupled to the measurement interface apparatus.

25. The method of claim 20, further comprising an additional mode that includes:

receiving a second reflected signal (S11) at the measurement interface apparatus from the input of the device under test; and

providing the second reflected signal to a second receiver disposed within the network analyzer.

26. The method of claim 20, further comprising an additional mode that includes:

receiving a generated signal (S21) at the measurement interface apparatus from the output of the device under test;

passing the generated signal through the input port of the main-line of the second air-line directional coupler disposed within the measurement interface apparatus to produce a coupled generated signal;

providing the coupled generated signal from the output port of the coupled-line of the second air-line directional coupler to the first attenuator to produce an attenuated generated signal; and

providing the attenuated generated signal to the first receiver disposed within the network analyzer.

27. The method of claim 20, further comprising:

providing the amplified second signal from a coupled output port of a directional coupler to a second attenuator to produce an attenuated reference signal (R1); and

providing the attenuated reference signal to a second receiver disposed within the network analyzer.

28. The method of claim 20, further comprising an additional mode that includes:

blocking the first signal such that it does not enter the input of the device under test;

providing a third signal (FS 1) to the input of the device under test, wherein the third signal is generated by the network analyzer coupled to the measurement interface apparatus and the third signal is provided by the measurement interface apparatus;

receiving a second reflected signal (s11) at the measurement interface apparatus from the input of the device under test; and

providing the second reflected signal to a second receiver disposed within the network analyzer.

29. The method of claim 20, further comprising an additional mode that includes:

blocking the first signal such that it does not enter the input of the device under test;

providing a third signal (FS 1) to the input of the device under test, wherein the third signal is generated by the network analyzer coupled to the measurement interface apparatus and the third signal is provided by the measurement interface apparatus;

receiving a generated signal (s21) at the measurement interface apparatus from the output of the device under test; and

providing the generated signal to the first receiver disposed within the network analyzer.

30. The method of claim 20, wherein the second signal is generated by the network analyzer, further comprising an additional mode that includes:

blocking the first signal such that it does not enter the input of the device under test;

providing the coupled second signal to an output of the device under test, wherein the device under test reflects a portion of the coupled second signal as a second reflected signal (s22);

passing the second reflected signal through the input port of the main-line of the second air-line directional coupler disposed within the measurement interface apparatus to a coupled-line of the second air-line directional coupler to provide a second coupled reflected signal;

providing the second coupled reflected signal from an output port of a coupled-line of the second air-line directional coupler to the first attenuator to produce a second attenuated reflected signal; and

providing the second attenuated reflected signal to the network analyzer.