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US 6,970,001 B2Granted
Variable impedance test probe
AssigneeHewlett-Packard Development Company, L.P.
InventorsSachin Navin Chheda, Robert William Dobbs, Andrew Barr
Life of this patent
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Abstract
A variable impedance test probe of the present invention comprises a first signal conductor, a first ground reference conductor, and a first dielectric element disposed between the first signal conductor and the first ground reference conductor. The dielectric element is configured to selectively vary an impedance of the first signal conductor relative to the ground reference conductor.
Claims15
A test probe comprising:
- a first conductor configured for carrying a first portion of a differential signal;
- a second conductor configured for carrying a second portion of a differential signal;
- a first variable dielectric chamber disposed between the first conductor and the second conductor and configured for holding a variable volume of dielectric fluid;
- a third ground reference conductor spaced from the first conductor;
- a second variable dielectric chamber disposed between the first conductor and the third ground reference conductor and configured for holding a variable volume of dielectric fluid to vary the distance between the first conductor and the third ground reference conductor;
- a fourth ground reference conductor spaced from the second conductor;
- a third variable dielectric chamber disposed between the second conductor and the fourth ground reference conductor and configured for holding a variable volume of dielectric fluid to vary the distance between the second conductor and the fourth ground reference conductor;
- and
- wherein varying the volume of one or more of the first, second, and third chambers results in varying the differential impedance of the first conductor and the second conductors relative to the third and fourth ground reference conductors.
6 more elements
A variable impedance test probe comprising:
- a first signal conductor and a first ground reference conductor;
- a first dielectric element disposed between the first signal conductor and the first ground reference conductor and being configured to vary an impedance of the first signal conductor relative to the first ground reference conductor;
- a second signal conductor;
- a second ground reference conductor;
- a second dielectric element disposed between the second signal conductor and the second ground reference conductor with the second dielectric element being configured to vary its volume for varying a distance between the second signal conductor and the second ground reference conductor to thereby vary an impedance of the second signal conductor relative to the first and second ground reference conductors;
- and
- a third dielectric element disposed between the first signal conductor and the second signal conductor with the third dielectric element being configured to vary its volume for varying a distance between the first signal conductor and the second signal conductor to thereby vary a differential impedance of the first and second signal conductors relative to the first and second ground reference conductors.
4 more elements
A variable impedance test probe system comprising:
- a test probe including:
- a first signal conductor and a first ground reference conductor;
- and
- a first dielectric element disposed between the first signal conductor and the first ground reference conductor and being configured to vary an impedance of the first signal conductor relative to the first ground reference conductor,
- wherein the first dielectric element comprises a first dielectric fluid chamber disposed between the first signal conductor and the first ground reference conductor, and configured to hold a dielectric fluid and configured for inflation and deflation with the dielectric fluid to vary the impedance of the first signal conductor relative to the first ground reference conductor by varying the volume of the dielectric fluid within the first chamber, and thereby varying a distance between the first signal conductor and the first ground reference conductor;
- and
- at least one test lead electrically coupled to, and extending from the test probe, for measuring test signal attributes in at least one target conductive element.
4 more elements
A test probe comprising:
- first means for carrying a first test signal relative to a ground reference;
- first means for dielectrically varying an impedance of the first test signal relative to the ground reference;
- first means, external to the first means for dielectrically varying an impedance and external to the first means for carrying, for applying the first test signal to at least one target conductive element;
- second means for carrying a second test signal relative to the ground reference;
- and
- second means for dielectrically varying the impedance of the first test signal and the second test signal relative to the ground reference;
- and
- second means, external to the first and second means for dielectrically varying the impedance and external to the first and second means for carrying, for applying the second test signal to the at least one target conductive element.
5 more elements
A method of testing signal integrity attributes, the method comprising:
- using at least one dielectric element to variably control an impedance of a probe, between a test signal conductor of the probe and a ground reference conductor of the probe, to substantially match an impedance of a pair of target conductive elements external to the probe wherein the test signal conductor and the ground reference conductor comprise a first test signal conductor of the probe spaced from a first ground reference conductor of the probe and a second test signal conductor of the probe spaced from a second ground reference conductor of the probe, and wherein the first test signal conductor is spaced from the second test signal conductor;
- and
- applying a test signal, via at least one test lead electrically coupled to and extending from the probe, to the pair of target conductive elements.
A test probe comprising:
- first means for carrying a first test signal relative to a ground reference including a first signal conductor and a first ground reference conductor;
- first means, for dielectrically varying an impedance of the first test signal relative to the ground reference, including a first inflatable bladder disposed between the first signal conductor and the first ground reference conductor, and configured for holding a variably controlled volume of dielectric fluid;
- and
- means, external to the first means for dielectrically varying an impedance and the first means for carrying, for applying the first test signal to at least one target conductive element.
1 more element
A method of testing signal integrity attributes in a pair of target conductive element, the method comprising:
- arranging a test probe to include a first test signal conductor spaced from a second ground reference conductor, and a second test signal conductor spaced from a second ground reference conductor, and the first test signal conductor spaced from the second test signal conductor;
- variably controlling an impedance of the probe to substantially match an impedance of the pair of target conductive elements by:
- varying the spacing between the first test signal conductor and the second test signal conductor by controlling, with a pump, a volume of dielectric fluid within a first inflatable chamber disposed between the spaced first test signal conductor and the second test signal conductor;
- and
- varying the spacing between the first test signal conductor and the first ground reference conductor and between the second test signal conductor and the second ground reference conductor by controlling, with a pump, a volume of dielectric fluid within each of a pair second inflatable chambers, with one of the second inflatable chambers disposed between the first test signal conductor and the first ground reference conductor and the other second inflatable chamber disposed between the second test signal conductor and the second ground reference conductor;
- and
- applying a test signal from the test probe to the pair of target conductive elements.
4 more elements
Dependencies are inferred from the claim text.