1. A magnetic resonance apparatus comprising:
a magnetic resonance scanner having a surface therein;
a gradient coil system disposed in said scanner; and
an adhesive disposed between said gradient coil system and said surface attaching said gradient coil system to said scanner, said adhesive having a melting temperature in a range between approximately 50\xb0 C. and 90\xb0 C.
2. A magnetic resonance apparatus as claimed in claim 1 wherein said gradient coil system has a surface facing said surface of said scanner, and wherein said adhesive is disposed between said surface of said scanner and said surface of said gradient coil system.
3. A magnetic resonance apparatus as claimed in claim 1 wherein said surface of said scanner forms a cavity in which said gradient coil system is disposed and attached.
4. A magnetic resonance apparatus as claimed in claim 3 wherein said cavity is cylindrical.
5. A magnetic resonance apparatus as claimed in claim 3 wherein said cavity has a middle region with a barrel shape.
6. A magnetic resonance apparatus as claimed in claim 1 wherein said gradient coil system comprises a plurality of gradient coils each formed by multiple sub-coils, and wherein respective parts of said sub-coils are respectively disposed in two structurally separate halves of said gradient coil system.
7. A magnetic resonance apparatus as claimed in claim 6 wherein said surface of said scanner forms a cavity in which said gradient coil system is disposed and attached, said cavity having a middle region with a barrel shape, and said halves being separated from each other and respectively disposed at opposite sides of said middle region.
8. A magnetic resonance apparatus as claimed in claim 7 wherein said gradient coil system comprises a carrier on which said halves are mounted separated from each other.
9. A magnetic resonance apparatus as claimed in claim 8 wherein said halves and said carrier each have a hollow cylindrical shape.
10. A magnetic resonance apparatus as claimed in claim 1 wherein said scanner comprises a basic field magnet having said surface to which said gradient coil system is attached.
11. A magnetic resonance apparatus as claimed in claim 1 wherein said adhesive is selected from the group consisting of hard foams and adhesive resins.
12. A magnetic resonance apparatus as claimed in claim 1 wherein said adhesive is a wax.
13. A magnetic resonance apparatus as claimed in claim 12 wherein said wax is selected from the group consisting of steam, paraffin and carnauba wax.
14. A magnetic resonance apparatus comprising:
a magnetic resonance scanner having a surface therein;
a gradient coil system disposed in said scanner;
an adhesive disposed between said gradient coil system and said surface attaching said gradient coil system to said scanner, said adhesive having a low melting temperature; and
said gradient coil system comprising at least one coil and a control unit connected to said at least one coil for controlling a quantity flowing in said coil to set a temperature of said gradient coil system, during operation of said scanner to acquire magnetic resonance data, that is below said melting temperature of said adhesive, said control unit also controlling said quantity to selectively increase said temperature of said gradient coil system above said melting temperature of said adhesive, allowing release of the attachment of said gradient coil system to said scanner.
15. A magnetic resonance apparatus as claimed in claim 14 wherein said gradient coil system comprises a plurality of gradient coils and wherein said at least one coil is at least one of said gradient coils, and wherein said quantity is current.
16. A magnetic resonance apparatus as claimed in claim 14 wherein said gradient coil system comprises a plurality of shielding coils, and wherein said at least one coil is at least one of said shielding coils, and wherein said quantity is current.
17. A magnetic resonance apparatus as claimed in claim 14 wherein said gradient coil system comprises a cooling coil and wherein said at least one coil is said cooling coil, and wherein said quantity is a fluid coolant.
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. A method of synchronizing an audio signal and a video signal comprising:
providing an input audio signal and an input video signal that have a synchronized phase relationship;
tagging the input video signal to provide a tagged video signal;
tagging the input audio signal to provide a tagged audio signal;
transmitting the tagged video and audio signals through a network;
analyzing the tagged audio and video signals to determine the extent to which the tagged audio and video signals are unsynchronized; and
providing a synchronization signal corresponding to the extent to which the tagged audio and video signals are unsynchronized;
wherein the input video signal is tagged by:
generating a correlation signal at a correlation signal bit frequency;
generating a video correlation waveform gain signal corresponding to the power level of the input video signal within a selected frequency range;
providing a video correlation signal based on the correlation signal and the video correlation waveform gain signal; and
adding the video correlation signal to the input video signal.
2. The method of claim 1 wherein the correlation signal corresponds to a pre-determined tagging sequence.
3. The method of claim 2 wherein the pre-determined tagging sequence is a bit sequence and the bit length of the bit sequence is selected based on the maximum synchronization error to be corrected.
4. The method of claim 1 wherein the correlation signal is generated with a correlation signal bit frequency that is within the pass band of the network.
5. The method of claim 1 wherein the correlation signal bit frequency is determined based at least in part on a video signal clock that is derived from the input video signal.
6. The method of claim 1 wherein the correlation signal bit frequency is determined based at least in part on the input audio signal.
7. The method of claim 1 wherein the correlation signal bit frequency is determined based on a clock signal not provided in the input audio signals signal or the input video signal.
8. The method of claim 1 wherein the correlation signal is well-behaved.
9. The method of claim 8 wherein the correlation signal is chosen to have a relatively high auto-correlation co-efficient when cross-correlated with an unshifted version of itself and to have relative low cross-correlation coefficients when cross-correlated with shifted versions of itself.
10. The method of claim 1 wherein the video correlation signal is provided by
smoothing the correlation signal to provide a video correlation waveform; and
scaling the video correlation waveform in response to the video correlation waveform gain signal.
11. The method of claim 1 wherein the video correlation waveform signal corresponds to the power level of the input video signal within the pass band of video processing and transmission elements in the network.
12. The method of claim 1 wherein the input audio signal is tagged by:
generating an audio correlation waveform gain signal corresponding to the power level of the input audio signal within a selected frequency range;
providing an audio correlation signal based on the correlation signal and the audio correlation waveform gain signal; and
adding the audio correlation signal to the input video signal.
13. The method of claim 12 wherein the video correlation signal is provided by
smoothing the correlation signal to provide an audio correlation waveform; and
scaling the audio correlation waveform in response to the audio correlation waveform gain signal.
14. The method of claim 12 wherein the video correlation waveform signal corresponds to the power level of the input audio signal within the pass band of audio processing and transmission elements in the network.
15. A method of synchronizing an audio signal and a video signal comprising:
providing an input audio signal and an input video signal that have a synchronized phase relationship;
tagging the input video signal to provide a tagged video signal;
tagging the input audio signal to provide a tagged audio signal;
transmitting the tagged video and audio signals through a network;
analyzing the tagged audio and video signals to determine the extent to which the tagged audio and video signals are unsynchronized; and
providing a synchronization signal corresponding to the extent to which the tagged audio and video signals are unsynchronized;
wherein the input audio signal is tagged by:
generating a correlation signal at a correlation signal bit frequency;
generating an audio correlation waveform gain signal corresponding to the power level of the input audio signal within a selected frequency range;
providing an audio correlation signal based on the correlation signal and the audio correlation waveform gain signal; and
adding the audio correlation signal to the input video signal.
16. The method of claim 15 wherein the audio correlation signal is provided by
smoothing the correlation signal to provide an audio correlation waveform; and
scaling the audio correlation waveform in response to the audio correlation waveform gain signal.
17. The method of claim 16 wherein the audio correlation waveform signal corresponds to the power level of the input audio signal within the pass band of audio processing and transmission elements in the network.
18. The method of any one of claim 1 wherein the audio and video signals are analyzed by:
generating a weighted tagged video signal corresponding to the tagged video signal;
sequentially comparing the weighted tagged video signal with a progressively shifted version of the correlation signal;
identifying a video offset value corresponding to a phase difference between the tagged video signal and a zero phase signal;
generating a weighted tagged audio signal corresponding to the tagged audio signal;
sequentially comparing the weighted audio video signal with a progressively shifted version of the correlation signal; and
identifying an audio offset value corresponding to a phase difference between the tagged video signal and the zero phase signal.
19. The method of claim 18 wherein the video offset value is identified in part by performing a leaky integration of a series of derivative values for the result of the comparison between the weighted tagged video signal and each progressively shifted version of the correlation signal between successive zero phase signals.
20. The method of claim 18 wherein the audio offset value is identified in part by performing a leaky integration of a series of derivative values for the result of the comparison between the weighted tagged audio signal and each progressively shifted version of the correlation signal between successive zero phase signals.
21. The method 18 wherein the synchronization signal is provided based on the difference between the video offset value and audio offset value.
22. The method claim 18 wherein the weighted tagged video signal is generated by filtering the tagged video signal across frequency components generally corresponding to frequency components of the correlation signal.
23. The method claim 18 wherein the weighted tagged audio signal is generated by filtering the tagged audio signal across frequency components generally corresponding to frequency components of the correlation signal.
24. The method of claim 1 wherein the correlation sequence is selected based on a transformation of the tagged video signal between tagging of the video signal and the analysis of tagged video signal.
25. The method of any one of claim 15 wherein the audio and video signals are analyzed by:
generating a weighted tagged video signal corresponding to the tagged video signal;
sequentially comparing the weighted tagged video signal with a progressively shifted version of the correlation signal;
identifying a video offset value corresponding to a phase difference between the tagged video signal and a zero phase signal;
generating a weighted tagged audio signal corresponding to the tagged audio signal;
sequentially comparing the weighted audio video signal with a progressively shifted version of the correlation signal; and
identifying an audio offset value corresponding to a phase difference between the tagged video signal and the zero phase signal.