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US 6,785,625 B1Granted
Characterizing multi-port cascaded networks
AssigneeNCR Corporation
InventorsJun Fan, Arthur R. Alexander, James L. Knighten, Norman W. Smith
Life of this patent
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Abstract
A test mechanism includes test equipment to measure frequency-domain data, such as scattering or S parameters. The S parameters are transformed to a different type of network parameters, such as transmission or T parameters. Contributions of test fixtures can be easily removed for the overall T-parameter matrix of a device under test connected in cascade with the test fixture. The test mechanism provides accurate measurement of a device under test represented by a multi-port (greater than two ports) network that is cascaded with another multi-port network representing the test fixture.
Claims30
A method of characterizing a device under test, comprising:
- receiving measured scattering parameters of a circuit including a test fixture and the device under test, each of the test fixture and device under test represented as a multi-port network having greater than two ports;
- transforming the scattering parameters to a first set of further network parameters, the further network parameters being different from the scattering parameters;
- and
- separating an effect of the test fixture from the first set of further network parameters to derive a second set of further network parameters to represent performance of the device under test.
1 more element
A method of characterizing a device under test, comprising:
- receiving measured scattering parameters of a circuit including a test fixture and the device under test, each of the test fixture and device under test represented as a multi-port network having greater than two ports;
- transforming the scattering parameters to a first set of further network parameters, the further network parameters being different from the scattering parameters;
- separating an effect of the test fixture from the first set of further network parameters to derive a second set of further network parameters to represent performance of the device under test,
- wherein transforming the scattering parameters to further network parameters comprises transforming the scattering parameters to transmission parameters, wherein the first set of transmission parameters comprises a first matrix of transmission parameters, and wherein the second set of transmission parameters comprises a second matrix of transmission parameters;
- storing a third matrix of transmission parameters representing the test fixture;
- and
- performing matrix multiplication of the first matrix of transmission parameters by an inverse of the third matrix of transmission parameters to derive the second matrix of transmission parameters,
- wherein the third matrix represents one portion of the test fixture;
- storing a fourth matrix of transmission parameters representing another portion of the test fixture connected to the device under test;
- and
- performing further matrix multiplication of the first matrix of transmission parameters by an inverse of the fourth matrix to derive the second matrix.
8 more elements
A test system comprising:
- a storage to store a first set of first network parameters to represent a test fixture;
- and
- a controller adapted to:
- receive a set of measured frequency-domain parameters for a circuit having the test fixture and a device under test, the frequency-domain parameters being of a different type than the first network parameters, and each of the test fixture and device under test being a multi-port network having greater than two ports;
- transform the set of measured frequency-domain parameters to a second set of first network parameters;
- and
- use the first set of first network parameters to remove a contribution of the test fixture from the second set of first network parameters.
4 more elements
An article comprising at least one storage medium containing instructions that when executed cause a test system to:
- store a first matrix of transmission parameters corresponding to a test fixture;
- receive measured data containing a matrix of scattering parameters corresponding to cascaded plural multi-port networks, one of the plural multi-port networks comprising the test fixture, and another one of the plural multi-port networks comprising a device under test, each multi-port network having greater than two ports;
- transform the matrix of scattering parameters to a second matrix of transmission parameters;
- and
- combine the second matrix with the first matrix to remove an effect of test fixture from the measured data.
2 more elements
An article comprising at least one storage medium containing instructions that when executed cause a test system to:
- store a first matrix of transmission parameters corresponding to a test fixture;
- receive measured data containing a matrix of scattering parameters corresponding to cascaded plural multi-port networks, one of the plural multi-port networks comprising the test fixture, and another one of the plural multi-port networks comprising a device under test, each multi-port network having greater than two ports;
- transform the matrix of scattering parameters to a second matrix of transmission parameters;
- combine the second matrix with the first matrix to remove an effect of test fixture from the measured data;
- derive a third matrix of transmission parameters based on combining the first and second matrices;
- and
- transform the third matrix of transmission parameters to another type of network parameters.
4 more elements
An article comprising at least one storage medium containing instructions that when executed cause a test system to:
- store a first matrix of transmission parameters corresponding to a test fixture;
- receive measured data containing a matrix of scattering parameters corresponding to cascaded plural multi-port networks, one of the plural multi-port networks comprising the test fixture, and another one of the plural multi-port networks comprising a device under test, each multi-port network having greater than two ports;
- transform the matrix of scattering parameters to a second matrix of transmission parameters;
- combine the second matrix with the first matrix to remove an effect of test fixture from the measured data;
- derive a third matrix of transmission parameters based on combining the first and second matrices;
- and
- transform the third matrix of transmission parameters to another matrix of scattering parameters to represent the device under test.
4 more elements
A method of characterizing a device under test in a test arrangement in which the device under test is coupled through a test fixture to test equipment, each of the device under test and test fixture comprising a multi-port network with greater than two ports, the method comprising:
- storing a first matrix of transmission parameters for the test fixture;
- receiving measured scattering parameters of cascaded multi-port networks including the device under test network and test fixture network;
- transforming the measured scattering parameters to a second matrix of transmission parameters;
- and
- performing a multiplication of the second matrix by an inverse of the first matrix to derive a third matrix of transmission parameters representing the device under test.
2 more elements
A method of characterizing a device under test, comprising:
- receiving measured scattering parameters of a circuit including a test fixture and the device under test, each of the test fixture and device under test represented as a multi-port network having greater than four ports;
- transforming the scattering parameters to a first set of further network parameters, the further network parameters being different from the scattering parameters;
- and
- separating an effect of the test fixture from the first set of further network parameters to derive a second set of further network parameters to represent performance of the device under test.
1 more element
A test system comprising:
- a storage to store a first set of first network parameters to represent a test fixture;
- and
- a controller adapted to:
- receive a set of measured frequency-domain parameters for a circuit having the test fixture and a device under test, the frequency-domain parameters being of a different type than the first network parameters, and each of the test fixture and device under test being a multi-port network having greater than four ports;
- transform the set of measured frequency-domain parameters to a second set of first network parameters;
- and
- use the first set of first network parameters to remove a contribution of the test fixture from the second set of first network parameters.
4 more elements
Dependencies are inferred from the claim text.