1. A housing of an implantable medical device, the housing comprising:
a first housing portion of a titanium alloy having a resistivity of greater than about 100 \u03bcOhm-cm formed by metal injection molding; and
a second housing portion joined in a rigidly fixed relationship to the first housing portion, the second housing portion being of the titanium alloy and formed by metal injection molding.
2. The housing of claim 1, wherein at least one of the housing portions has a region of reduced wall thickness formed by a chemical removal process.
3. The housing of claim 1, wherein the first housing portion includes a region having a wall thickness of less than about 0.015 inches.
4. The housing of claim 3, wherein the second housing portion includes a region having a wall thickness of less than about 0.015 inches.
5. The housing of claim 4, wherein the first housing portion includes a first rim and the second housing portion includes a second rim, and wherein the first and second rims are welded together.
6. The housing of claim 5, wherein the first and second rims have a wall thickness of greater than about 0.015 inches.
7. The housing of claim 1, wherein the titanium alloy includes at least one of aluminum, vanadium and molybdenum.
8. The housing of claim 7, wherein the titanium alloy includes titanium, aluminum and vanadium.
9. The housing of claim 1, wherein the titanium alloy comprises a one of: a Ti6Al4V alloy, a Ti8AlMo-IV alloy, a Ti6242 alloy, an SP-700 alloy, a Ti5Al2.5Sn alloy, and a Ti3Al2V alloy.
10. The housing of claim 1, wherein the titanium alloy includes ceramic particles.
11. The housing of claim 10, wherein the ceramic particles include at least one of titanium carbide, titanium dioxide and silicon carbide.
12. The housing of claim 1, wherein the titanium alloy has a tensile yield strength of greater than about 500 Mpa.
13. The housing of claim 1, wherein the titanium alloy comprises an \u03b1 Ti or near \u03b1 Ti alloy.
14. The housing of claim 1, wherein the titanium alloy has a resistivity of about 100 \u03bcOhm-cm to about 220 \u03bcOhm-cm.
15. The housing of claim 14, wherein the titanium alloy has a resistivity of about 125 \u03bcOhm-cm to about 190 \u03bcOhm-cm.
16. A method for forming the housing of an implantable medical device, the method comprising:
forming a first housing portion by metal injection molding a titanium alloy;
selectively reducing the wall thickness of at least one region of the first housing portion;
forming a second housing portion by metal injection molding the titanium alloy; and
joining the first housing portion and the second housing portion by creating a metallic weld to produce the housing of the implantable medical device.
17. The method of claim 16, wherein forming the first housing portion comprises:
injecting a mixture of metal alloy constituent particles and a polymer into a mold to form the first housing portion;
heating the first housing portion to remove the polymer; and
sintering the first housing portion.
18. The method of claim 17, wherein the metal alloy constituent particles include titanium and at least one of aluminum, vanadium, and molybdenum.
19. The method of claim 17, wherein the mixture further includes ceramic particles.
20. The method of claim 16, wherein selectively reducing the wall thickness is by chemical removal.
21. An implantable medical device comprising:
a housing of at least two portions with each of the at least two portions formed of a titanium alloy having a resistivity of greater than about 100 \u03bcOhm-cm with each of the at least two portions also being formed by metal injection molding, and with each of the at least two portions being joined by a metallic weld;
a rechargeable power source within the housing; and
electronic circuitry within the housing and powered by the rechargeable power source.
22. The implantable medical device of claim 21, wherein the housing has a first face with a wall thickness of less than about 0.015 inches.
23. The implantable medical device of claim 22, wherein the first face has a wall thickness of about 0.008 to about 0.012 inches.
24. The implantable medical device of claim 22, wherein the first face wall thickness is formed by a chemical removal process.
25. The implantable medical device of claim 21, and further comprising:
a coil for receiving electromagnetic energy to charge the rechargeable power source, the coil positioned within the housing adjacent the first face.
26. The implantable medical device of claim 21, wherein the titanium alloy includes at least one of aluminum, vanadium and molybdenum.
27. The implantable medical device of claim 26, wherein the titanium alloy includes titanium, aluminum and vanadium.
28. The implantable medical device of claim 21, wherein the titanium alloy comprises a one of: a Ti6A14V alloy, a Ti8AlMo-IV alloy, a Ti6242 alloy, an SP-700 alloy, a Ti5Al2.5Sn alloy, and a Ti3Al2V alloy.
29. The implantable medical device of claim 21, wherein the titanium alloy includes ceramic particles.
30. The implantable medical device of claim 29, wherein the ceramic particles include at least one of titanium carbide, titanium dioxide and silicon carbide.
31. The implantable medical device of claim 21, wherein the titanium alloy has a tensile yield strength of greater than about 500 Mpa.
32. The implantable medical device of claim 21, wherein the titanium alloy comprises an \u03b1 Ti or near a Ti alloy.
33. The implantable medical device of claim 21, wherein the titanium alloy has a resistivity of about 100 \u03bcOhm-cm to about 220 \u03bcOhm-cm.
34. The implantable medical device of claim 33, wherein the titanium alloy has a resistivity of about 125 \u03bcOhm-cm to about 190 \u03bcOhm-cm.
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 orthogonally-multiplexed orthogonal amplitude modulation method, comprising the steps of:
generating 2N-dimensional basis signals, all the 2N-dimensional basis signals and their time-shift signals being mutually orthogonal;
partitioning the 2N-dimensional basis signals into M basis signals subsets;
generating M supersymbols corresponding to the M basis signals subsets at a signal time, each supersymbol having L+1 symbols consisting of 1 orthogonal symbol and L amplitude symbols, wherein each amplitude symbol having K amplitude levels;
selecting L basis signals out of each one of the M basis signals subsets according to each corresponding supersymbol of the M supersymbols at the signal time;
modulating each supersymbol of the M supersymbols with the corresponding L basis signals to form M component signals; and
multiplexing the M component signals to form an orthogonally-muhiplexed orthogonal amplitude modulation signal;
wherein N, M, L, and K are positive integers.
2. The orthogonally-multiplexed orthogonal amplitude modulation method as claimed in claim 1 wherein each one of the M component signals has a dimensionality of Nc=2NM and N, M, L, K and Nc are all integer power of two.
3. The orthogonally-multiplexed orthogonal amplitude modulation method as claimed in claim 1 wherein the orthogonal symbol is NcL-ary symbol.
4. The orthogonally-multiplexed orthogonal amplitude modulation method as claimed in claim 1 wherein the amplitude symbols is LK-ary symbols.
5. The orthogonally-multiplexed orthogonal amplitude modulation method as claimed in claim 1 wherein L\u22674.
6. The orthogonally-multiplexed orthogonal amplitude modulation method as claimed in claim 1 wherein NcL>1 and K\u22674.
7. The orthogonally-multiplexed orthogonal amplitude modulation method as claimed in claim 1 wherein N is given the constraints 1\u2266M\u22662N, 1\u2266Nc\u22662N, and 1\u2266L\u2266Nc.
8. The orthogonally-multiplexed orthogonal amplitude modulation method as claimed in claim 1 comprising the demodulation steps of:
generating predictive supersymbol at the signal time;
modulating the predictive supersymbol with the L basis signals to form a predictive signal; and
choosing the predictive supersymbols to minimize a mean-square-error of the predictive signal and a actual received signal.
9. The orthogonally-multiplexed orthogonal amplitude modulation method as claimed in claim 1 comprising the demodulation steps of:
generating predictive supersymbol at the signal time;
generating L correlation measurements according to a actual received signal and the 2N-dimension basis signals at the signal time; and
choosing one of the predictive supersymbols to maximize a difference between the inner-product of the amplitude symbols and the L correlation measurements and the self inner-product of the amplitude symbols.
10. An orthogonally-multiplexed orthogonal amplitude modulation device, comprising:
M orthogonal basis signal sources, generating 2N-dimensional basis signals partitioned into M basis signals subsets corresponding to the M orthogonal basis signals; wherein all the 2N-dimensional basis signals and their time-shift signals are mutually orthogonal;
M supersymbol sources, generating M supersyrnbols corresponding to the M basis signals subsets at a signal time, wherein each supersymbol having L+1 symbols consisting of 1 orthogonal symbol and L amplitude symbols, each amplitude symbol having K amplitude levels;
M modulators, forming M component signals by modulating M supersymbols with M sets of corresponding L basis signals selected out of the M basis signals subsets according to the corresponding supersymbol and at the signal time; and
a multiplex, multiplexing the M component signals to form an orthogonally-multiplexed orthogonal amplitude modulation signal;
wherein N, M, L, and K are positive integers.
11. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 wherein each one of the M component signals has a dimensionality of Nc=2NM.
12. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 wherein the orthogonal symbol is NcL-ary symbol.
13. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 wherem the amplitude symbols is LK-ary symbols.
14. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 wherein L\u22674.
15. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 wherein NcL>1 and K\u22674.
16. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 wherein N, M, L, K, and Nc are all integer power of two.
17. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 wherein N is given the constraints 1\u2266M\u22662N, 1\u2266Nc\u22662N, and 1\u2266L\u2266Nc.
18. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 comprising:
a predict device, generating predictive supersymbol at the signal time;
a synthesis device, modulating the supersymbol with the L basis signals to form a predictive signal, and choosing the predictive supersymbol to minimize a mean-square-error of the predictive signal and a actual received signal.
19. The orthogonally-multiplexed orthogonal amplitude modulation device as claimed in claim 10 comprising:
a predict device, generating predictive supersymbol at the signal time;
a correlation measurement device, generating L correlation measurements according to a actual received signal and the 2N-dimension basis signals at the signal time; and
a synthesis device, choosing the predictive supersymbol to maximize a difference between the inner-product of the amplitude symbols and the L correlation measurements and the self inner-product of the amplitude symbols.