Method for de-embedding in network analysis

• US 9,194,930 B2
• Filed: 06/20/2011
• Issued: 11/24/2015
• Est. Priority Date: 06/20/2011
• Status: Active Grant

• Current Assignee: Teledyne LeCroy, Inc. (Teledyne Technologies Incorporated)
• Original Assignee: Teledyne LeCroy, Inc. (Teledyne Technologies Incorporated)
• Inventors: Pupalaikis, Peter J.
• Primary Examiner(s): Kundu, Sujoy
• Assistant Examiner(s): Ngon, Ricky
• Application Number:
  US13/163,914
• Publication Number:
  US 20120323505A1
• Time in Patent Office: 1,618 Days
• Field of Search: 324637-646, 702/189
• US Class Current: 1/1
• 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
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence
• CPC Class Codes: H04Q 2213/1316 Service observation, testing

Abstract

A method is provided for de-embedding fixtures and/or probes from measurements of devices where probes and fixtures are connected between the ports of a network analysis instrument and a device-under-test.

Claims

1. A system for calculating one or more device under test network parameters, comprising:

first and second robes for probing printed circuit board trace and measuring one or more measurement phase system network parameters for a system comprising a device under test and one or more connection elements;

first and second cables corresponding to the first and second probes for transferring the measured one or more measurement phase system network parameters;

first and second ports of a measurement instrument corresponding to the first and second cables receiving the transferred, measured one or more measurement phase system network parameters, the measurement instrument further comprising a processor, the processor performing the steps of;

calculating a measurement phase connection element impedance profile including an electrical length and a loss characteristic for each of the one or more connection elements in accordance with at least the measured one or more measurement phase system network parameters;

generating a measurement phase connection element representative model of each of the one or more connection elements in accordance with at least the corresponding calculated measurement phase connection element impedance profile and electrical length and loss characteristic; and

calculating one or more device under test network parameters by removing any effects of the one or more connection elements at the corresponding electrical length from the measurement phase system network parameters.

2. The system of claim 1, wherein the step of calculating the one or more device under test network parameters further comprises the steps of:

calculating one or more measurement phase connection element network parameters in accordance with each measurement phase connection element representative model of each of the one or more connection elements; and

removing the one or more measurement phase connection element representative model for each of the one or more connection elements from the measurement of the one or more measurement phase system network parameters.

3. The system of claim 1 wherein the step of generating the measurement phase connection element representative model of each of the one or more connection elements further comprises the steps of:

approximating the effect of the connection element as a sequence of one or more transmission line sections, wherein each of the one or more transmission line sections is defined by an impedance in accordance with the corresponding measurement phase connection element impedance profile; and

mathematically cascading the one or more transmission line sections.

4. The system of claim 3, wherein each of the one or more transmission line sections is further defined in accordance with a predetermined connection element loss characteristic.

5. The system of claim 3, wherein each of the one or more transmission line sections is further defined in accordance with a predetermined connection element group delay characteristic.

6. The system of claim 1, wherein the measurement phase connection element representative model is further defined in accordance with a predetermined connection element loss characteristic.

7. The system of claim 1, wherein the measurement phase connection element representative model is further defined in accordance with a predetermined connection element group delay characteristic.

8. The system of claim 1, wherein the calculation of the measurement phase connection element impedance profile for each of the one or more connection elements further comprises the steps of:

determining an impedance of the connection element at a plurality of times, wherein the impedance at each of the plurality of times is calculated in accordance with the steps of;

(a) calculating a reflection coefficient at the first interface of a system characterized by measurement phase return loss system network parameters in accordance with the measurement phase system network parameters;

(b) calculating new measurement phase return loss system network parameters with the calculated reflection coefficient effect removed therefrom; and

(c) repeating steps (a) and (b) employing the new calculated measurement phase return loss system network parameters calculated in step (b) substituted for the measurement phase return loss system network parameters until an electrical length is reached.

9. A system for calculating one or more calibration phase connection element network parameters for one or more connection elements, comprising:

first and second robes for probing printed circuit board trace for measuring one or more calibration phase system network parameters for a system comprising one or more measurement standards and one or more connection elements;

first and second cables corresponding to the first and second probes;

first and second ports of a measurement instrument corresponding to the first and second cables, the measurement instrument further comprising a processor, the processor performing the steps of;

calculating a calibration phase system port impedance profile including an electrical length and a loss characteristic for each of the one or more system ports in accordance with at least the measured calibration phase system network parameters;

generating a calibration phase connection element representative model of each of the one or more connection elements including electrical length and loss characteristic in accordance with at least the corresponding calculated calibration phase system port impedance profile; and

calculating one or more calibration phase connection element network parameters of each of the one or more connection elements in accordance with each corresponding calibration phase connection element representative model and electrical length.

10. The system of claim 9, wherein the step of generating the calibration phase connection element representative model of each of the one or more connection elements further comprises the steps of:

identifying a calibration phase connection element impedance profile as a portion of the calibration phase system port impedance profile; and

generating the calibration phase connection element representative model in accordance with the identified calibration phase connection element impedance profile.

11. The system of claim 9, wherein the calculation of the one or more calibration phase connection element network parameters of each of the one or more connection elements is performed by tuning the corresponding calibration phase connection element representative model such that one or more calculated calibration phase system network parameters with the effects of the connection elements removed substantially match one or more predetermined standard network parameters.

12. The system of claim 9, wherein the calculation of the one or more calibration phase connection element network parameters of each of the one or more connection elements is performed by tuning the corresponding calibration phase connection element representative model such that the one or more calibration phase system network parameters matches one or more calculated standard network parameters with the effects of the connection elements added thereto.

13. The system of claim 9, further comprising the step of calculating a connection element loss characteristic in accordance with the calculated calibration phase connection element network parameters.

14. The system of claim 9, further comprising the step of calculating a connection element group delay characteristic in accordance with the calculated calibration phase connection element network parameters.

15. A system for calculating one or more device under test network parameters, comprising:

first and second robes for probing printed circuit board trace;

first and second cables corresponding to the first and second probes;

first and second ports of a measurement instrument corresponding to the first and second cables, the measurement instrument further comprising a processor, the processor performing the steps of;

in a calibration phase;

measuring in accordance with the first and second probes one or more calibration phase system network parameters for a system comprising one or more measurement standards and one or more connection elements;

calculating a calibration phase system port impedance profile including an electrical length and a loss characteristic for each of the one or more system ports in accordance with at least the measured calibration phase system network parameters;

generating a calibration phase connection element representative model for each of the one or more connection elements including electrical length and loss characteristic in accordance with at least the corresponding calculated calibration phase system port impedance profile; and

calculating one or more calibration phase connection element network parameters of each of the one or more connection elements in accordance with each corresponding calibration phase connection element representative model including the electrical length;

wherein the calculation of the one or more calibration phase connection element network parameters of each of the one or more connection elements is performed by tuning the corresponding calibration phase connection element representative model such that one or more calculated calibration phase system network parameters with the effects of the connection elements removed match one or more predetermined standard network parameters; and

in a measurement phase;

measuring in accordance with the first and second probes one or more measurement phase system network parameters for a system comprising a device under test and one or more connection elements; and

calculating one or more device under test network parameters by removing any effects of the one or more connection elements from the measurement phase system network parameters.

16. The system of claim 15, wherein the effects of the one or more connection elements is determined in accordance with the one or more calibration phase connection element network parameters.

17. The system of claim 16, wherein the effects of the one or more connection elements are removed by de-embedding the calibration phase connection element network parameters from the measurement phase system network parameters.

18. The system of claim 15, further comprising the steps of:

in the calibration phase;

determining a connection element electrical length in accordance with the calculated calibration phase system port impedance profile;

in the measurement phase;

calculating a measurement phase connection element impedance profile for each of the one or more connection elements in accordance with at least the measured measurement phase system network parameters, each measurement phase connection element impedance profile spanning the determined connection element electrical length; and

generating a measurement phase connection element representative model of each of the one or more connection elements in accordance with at least the corresponding calculated measurement phase connection element impedance profile;

whereby the step of calculating the one or more device under test network parameters is performed by removing effects of the one or more connection elements from the measurement phase system network parameters in accordance with the measurement phase connection element representative model of the one or more connection elements.

19. The system of claim 15, further comprising the steps of:

in the calibration phase;

determining a connection element loss characteristic in accordance with the calibration phase system network parameters;

in the measurement phase;

calculating a measurement phase connection element impedance profile for each of the one or more connection elements in accordance with at least the determined connection element loss characteristic, each measurement phase connection element impedance profile spanning a determined connection element electrical length; and

generating a measurement phase connection element representative model of each of the one or more connection elements in accordance with at least the corresponding calculated measurement phase connection element impedance profile;

whereby the step of calculating one or more device under test network parameters is performed by removing effects of the one or more connection elements from the measurement phase system network parameters in accordance with the measurement phase connection element representative model of the one or more connection elements.

20. The system of claim 15, further comprising the steps of:

in the calibration phase;

determining a connection element group delay characteristic in accordance with the calibration phase system network parameters;

in the measurement phase;

calculating a measurement phase connection element impedance profile for each of the one or more connection elements in accordance with at least the determined connection element group delay characteristic, each measurement phase connection element impedance profile spanning a determined connection element electrical length; and

generating a measurement phase connection element representative model of each of the one or more connection elements in accordance with at least the corresponding calculated measurement phase connection element impedance profile;

whereby the step of calculating one or more device under test network parameters is performed by removing effects of the one or more connection elements from the measurement phase system network parameters in accordance with the measurement phase connection element representative model of the one or more connection elements.