| Title: |
Self Calibration Apparatus And Methods |
| Document Number: |
20080204039 |
| Publication Date: |
August 28, 2008 |
| Appl. No: |
11/677710 |
| Application Filed: |
February 22, 2007 |
| Abstract: |
The present invention is a method to allow a vector network analyzer (VNA) to self calibrate without the addition of calibration standards, e.g. a calibration kit with a network analyzer. |
| Inventors: |
Wong, Kenneth H. (Santa Rosa, CA, US); Liu, James C. (Santa Rosa, CA, US); Anderson, Keith F. (Santa Rosa, CA, US); Wong, Bobby Y. (Stockton, CA, US) |
| Claim: |
1. A method of calibrating comprising: for an instrument having N ports, where N>=2, characterizing cables having a first type including, connecting a first cable between the two calibrated ports, performing an “unknown-thru” full two-port calibration between the two ports, obtaining a S-parameter of the first cable, saving the S-parameter of the first cable in an internal dedicated user memory, and repeating connecting, performing, obtaining and saving for additional cables having the first type; disconnecting the cables having the first type from one of the two calibrated ports and transferring the measurement plane from the connected end of the cable to the disconnected end of the cable; and characterizing cables having a second type including, connecting a second cable between the second of the two calibrated ports and the first cable, measuring the S-parameter of the second type, and saving the S-parameter of the second cable in the internal dedicated user memory,and wherein the first and second mating types are selected from a group including female to female, male to male, and male to female connectors. |
| Claim: |
2. A method as defined in claim 1, wherein the characterized cables are used to calibrate the remaining N-2 ports having a matable connector to the cable, using the QSOLT method. |
| Claim: |
3. A method as defined in claim 1, the instrument including: a signal source; a switch, connecting to the signal source and operable to connect to each of the N ports; each of the N ports connecting to a block that includes, a dual reflectometer having an input sensing arm connected to a reference receiver and an output sensing arm connected to a test receiver, a three terminal switch, having a first terminal connected to a reflectometer, a second terminal connected to a multi-state impedance module, and a third terminal connected to a test port connector, |
| Claim: |
4. A method as defined in claim 1, comprising correcting mismatch power measurements using power calibrated receivers and characterized cables and adapters. |
| Claim: |
5. A method as defined in claim 1, wherein the calibrations can be updated without any external calibration standards. |
| Claim: |
6. A method of calibrating comprising: for an instrument having N ports, where N>=2, connecting a cable of a characterized type between the first port and a second port with the signal source connected to the first port side and the multi-state impedance module connected to the second port; performing a one port calibration at end of cable using the multi-state impedance in the second port; switching the second port to the reflectometer; and measuring the thru connection to complete a 2-port calibration. |
| Claim: |
7. A method as defined in claim 6, the instrument including: a signal source; a source switch connecting to the signal source and operable to connect to each of the N ports; each of the N ports connecting to a block that includes, a power splitter, connected to the signal source, having a first splitter output connected to a reference channel receiver; and a second splitter output of the power splitter connected to the common pole of a single pole, N throw switch, each throw connected to a block including, a single reflectometer having input port connected to the source switch and an output arm connected to a test receiver, a three position switch, connected to the output port of the single reflectometer, connected to the test port connector, a multi state impedance module connected to the three position switch. |
| Claim: |
8. A method as in claim 7, when the multi-state impedance module is electrically connected to the test port connector, it is used for calibrating another port. |
| Claim: |
9. A method as in claim 7, when the multi-state impedance module is electrically connected to the test port connector, it is used as variable impedance termination for a device under test. |
| Claim: |
10. A method as defined in claim 6 comprising: connecting a cable of a characterized type between the first port and a second port with the signal source connected to the first port side and the multi-state impedance module connected to the second port; performing a one port calibration at end of cable using the multi-state impedance in the second port; switching the second port to the reflectometer; and measuring the thru connection to complete a 2-port calibration. |
| Claim: |
11. A method as defined in claim 10 comprising: computing S-parameter of the cable using the internally generated 1-port calibration at the first port and the 1-port calibration at end of cable at the second port; saving the S-parameter of the first cable of the first characterized type in the internal dedicated user memory, and repeating computing and saving for additional cables having the same mating type; for a cable of a second characterized type, connecting a second cable between the second of the two calibrated ports and the first cable of the first characterized type, measuring the S-parameter of the cable of the second characterized type, and save the data in the internal dedicated user memory space; wherein the first and second characterized types are selected from a group including female to female, male to male, and male to female connectors. |
| Claim: |
12. A method as defined in claim 6, comprising correcting mismatch power measurements using power calibrated receivers and characterized cables and adapters. |
| Claim: |
13. A method as defined in claim 6 wherein the calibrations can be updated without any external calibration standards. |
| Claim: |
14. An instrument having N ports, where N>=2, comprising: a signal source; and a single pole, double throw switch, having a common pole connected to a second splitter output, each throw connected to a block including, a three terminal switch, having a first terminal connected to a reflectometer, a second terminal connected to a multi-state impedance module, and a third terminal connected to a test port connector, wherein the reflectometer is selected from a group including single and dual reflectometers. |
| Claim: |
15. A system as defined in claim 14, wherein the reflectometer is a single reflectometer, further including a a power splitter, connected to the signal source, having a first splitter output connected to a reference channel receiver. |
| Claim: |
16. A system as in claim 14, when the multi-state impedance module is electrically connected to the test port connector, it is used for calibrating another port. |
| Claim: |
17. A system as in claim 14, when the multi-state impedance module is electrically connected to the test port connector, it is used as variable impedance termination for a device under test. |
| Current U.S. Class: |
324/601 |
| Current International Class: |
01; 01 |
| Accession Number: |
edspap.20080204039 |
| Database: |
USPTO Patent Applications |
