1. A device comprising:
a first optical fiber having a first end and a second end;
a second optical fiber having a third end and a fourth end;
a first transmitting optical subassembly attached to the first end of the first optical fiber;
a second transmitting optical subassembly attached to the fourth end of the second optical fiber;
a first receiving optical subassembly attached to the second end of the first optical fiber;
a second receiving optical subassembly attached to the third end of the second optical subassembly;
a first circuit board attached to the first transmitting optical subassembly and to the first receiving optical subassembly;
a second circuit board attached to the second transmitting optical subassembly and to the second receiving optical subassembly;
a first amount of over-molding material surrounding the first transmitting optical subassembly and the first receiving optical subassembly; and
a second amount of over-molding material surrounding the second transmitting optical subassembly and the second receiving optical subassembly.
2. A device according to claim 1 wherein the first circuit board includes a first card edge connector, and the second circuit board includes a second card edge connector.
3. A device according to claim 2 wherein the first card edge connector includes a first set of contact traces, and wherein the second card edge connector contains a second set of contact traces.
4. A device comprising:
a first optical fiber having a first end and a second end;
a second optical fiber having a third end and a fourth end;
a first transmitting optical subassembly attached to the first end of the first optical fiber;
a second transmitting optical subassembly attached to the fourth end of the second optical fiber;
a first receiving optical subassembly attached to the second end of the first optical fiber;
a second receiving optical subassembly attached to the third end of the second optical subassembly;
a first circuit board attached to the first transmitting optical subassembly and to the first receiving optical subassembly;
a second circuit board attached to the second transmitting optical subassembly and to the second receiving optical subassembly;
a first amount of over-molding material surrounding the first transmitting optical subassembly and the first receiving optical subassembly;
a second amount of over-molding material surrounding the second transmitting optical subassembly and the second receiving optical subassembly;
a first housing attached to the first amount of over-molding material, wherein the first housing is conductive; and
a second housing attached to the second amount of over-molding material, wherein the second housing is conductive.
5. A device according to claim 4 wherein the first circuit board includes a first card edge connector, and the second circuit board includes a second card edge connector.
6. A device according to claim 5 wherein the first card edge connector includes a first set of contact traces, and wherein the second card edge connector contains a second set of contact traces.
7. A device comprising:
a first optical fiber having a first end and a second end;
a second optical fiber having a third end and a fourth end;
a first transmitting optical subassembly attached to the first end of the first optical fiber;
a second transmitting optical subassembly attached to the fourth end of the second optical fiber;
a first receiving optical subassembly attached to the second end of the first optical fiber;
a second receiving optical subassembly attached to the third end of the second optical subassembly;
a first circuit board attached to the first transmitting optical subassembly and to the first receiving optical subassembly;
a second circuit board attached to the second transmitting optical subassembly and to the second receiving optical subassembly;
a first amount of over-molding material surrounding the first transmitting optical subassembly and the first receiving optical subassembly;
a second amount of over-molding material surrounding the second transmitting optical subassembly and the second receiving optical subassembly;
a first housing attached to the first amount of over-molding material, wherein the first housing is conductive;
a second housing attached to the second amount of over-molding material, wherein the second housing is conductive;
a first ground clip attached to the first housing; and
a second ground clip attached to the second housing.
8. A device according to claim 7 wherein the first circuit board includes a first card edge connector, and the second circuit board includes a second card edge connector.
9. A device according to claim 8, further comprising a first release lever mechanically associated with first housing and the first ground clip, and a second release lever mechanically associated with the second housing and the second ground clip.
10. A device according to claim 9 wherein the first card edge connector includes a first set of contact traces, and wherein the second card edge connector contains a second set of contact traces.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An excitation system comprising:
a pair of piezoelectric elements configured to apply respective excitation forces to a test structure;
a clamp comprising an adjustable arm, the adjustable arm being configured to capture the test structure between the pair of piezoelectric elements;
a controller coupled to the pair of piezoelectric elements and configured to generate a respective excitation control signal for each piezoelectric element, each excitation control signal being configured such that the respective excitation forces are matched to one another; and
a pair of sensor film structures to generate respective output signals indicative of the excitation forces applied to the test structure, each sensor film structure being disposed between a respective one of the pair of piezoelectric elements and the test structure.
2. The excitation system of claim 1, wherein the adjustable arm is positioned such that the pair of piezoelectric elements, the pair of sensor film structures, and the test structure are clamped under a compressive force during application of the excitation forces.
3. The excitation system of claim 1, wherein each piezoelectric element comprises a respective piezoelectric stack, each piezoelectric stack comprising a plurality of piezoelectric layers.
4. The excitation system of claim 1, wherein the clamp is configured such that the respective excitation forces are collinear.
5. The excitation system of claim 1, wherein the control signals are configured such that the respective excitation forces are equal.
6. The excitation system of claim 1, wherein the control signals are configured such that the respective excitation forces are synchronized to displace the test structure in a common direction.
7. The excitation system of claim 1, wherein the pair of piezoelectric elements are configured such that each excitation force is applied orthogonally to a respective surface of the test structure.
8. The excitation system of claim 1, wherein each sensor film structure comprises a piezoelectric layer configured to present a mass negligible relative to a mass of the test structure.
9. The excitation system of claim 8, wherein each piezoelectric layer comprises a polyvinylidene fluoride layer.
10. The excitation system of claim 1, further comprising a further piezoelectric element in contact with the clamp and positioned to suppress a vibration mode of the clamp.
11. The excitation system of claim 10, wherein the further piezoelectric element is coupled to the controller, and wherein the controller is further configured to generate a vibration suppression control signal configured such that the further piezoelectric element suppresses the vibration mode of the clamp.
12. The excitation system of claim 10, wherein the further piezoelectric element comprises a piezoelectric patch disposed on the adjustable arm of the clamp.
13. The excitation system of claim 1, wherein the clamp is configured with a mass such that respective resonant frequencies of the clamp and the test structure are spaced from one another.
14. The excitation system of claim 1, further comprising a vibrometer disposed adjacent the test structure for optical communication with the test structure to obtain an indication of a motion response to the excitation forces applied to the test structure.
15. A method of force measurement in an excitation system comprising a pair of piezoelectric elements, the method comprising:
applying matching excitation forces via the pair of piezoelectric elements to a test structure compressed between the pair of piezoelectric elements; and
measuring the applied excitation forces via a pair of sensor film structures, each sensor film structure being disposed between a respective one of the pair of piezoelectric elements and the test structure and further comprising clamping the pair of piezoelectric elements, the pair of sensor film structures, and the test structure under a compressive force while applying the matching excitation forces.
16. The method of claim 15, wherein applying the excitation forces comprises generating a respective control signal for each piezoelectric element.
17. The method of claim 16, wherein the control signals are configured such that the respective excitation signals are equal and synchronized to displace the test structure in a common direction.
18. The method of claim 15, further comprising suppressing motion in a clamp used in compressing the test structure.
19. The method of claim 18, wherein suppressing the motion comprises providing a suppression control signal to a piezoelectric patch disposed on the clamp.
20. The method of claim 15, further comprising capturing data indicative of motion of the test structure in response to the applied matching excitation forces.
21. The excitation system of claim 1, wherein the pair of piezoelectric elements, the pair of sensor film structures, and the test structure are pre-compressed by the clamp.