1. A method for determining a reference phase in a radio communication system, which uses orthogonal M-ary codes, comprising:
receiving a radio signal;
demodulating the received radio signal to obtain in-phase component and quadrature component;
transforming the in-phase component and the quadrature component into correlation values for the M-ary codes by fast Hadamard transform or inverse Hadamard transform;
obtaining sums of square of the correlation value of the in-phase component and square of the correlation value of the quadrature component for the M-aray codes; and
selecting a maximum sum among the sums for the M-aray codes and providing phase information corresponding to the maximum sum based on corresponding correlation values as the reference phase to coherent detection unit.
2. The method according to claim 1, wherein
the phase information is used to rotate phase with respect to the in-phase component and the quadrature component for the coherent detection.
3. The method according to claim 1, wherein the phase information is filtered by using moving average process before providing to he coherent unit.
4. The method according to claim 1, wherein the phase information is filtered by using primary linear interpolation filter before providing to he coherent unit.
5. The method according to claim 3, wherein the phase information is filtered by using primary linear interpolation filter before providing to he coherent unit and after filtering by the moving average process.
6. A method for determining a reference phase in a radio communication system, which uses orthogonal M-ary codes and a spreading code, comprising:
receiving a radio signal;
demodulating and de-spreading the received radio signal to obtain in-phase component and quadrature component;
transforming the in-phase component and the quadrature component into correlation values for the M-ary codes by fast Hadamard transform or inverse Hadamard transform;
obtaining sums of square of the correlation value of the in-phase component and square of the correlation value of the quadrature component for the M-aray codes; and
selecting a maximum sum among the sums for the M-aray codes and providing phase information corresponding to the maximum sum based on corresponding correlation values as the reference phase to coherent detection unit.
7. The method according to claim 6, wherein the phase information is filtered by using moving average process before providing the he coherent unit.
8. The method according to claim 6, wherein the phase information is filtered by using primary linear interpolation filter before providing the he coherent unit.
9. The method according to claim 8, wherein the phase information is filtered by using primary linear interpolation filter before providing the he coherent unit and after filtering by the moving average process.
10. A method for determining a reference phase in a radio communication system, which uses orthogonal M-ary codes and a spreading code, comprising:
receiving a radio signal;
demodulating and de-spreading the received radio signal to obtain in-phase component and quadrature component;
transforming the in-phase component and the quadrature component into correlation values for the M-ary codes by fast Hadamard transform or inverse Hadamard transform;
obtaining sums of square of the correlation value the in-phase component and square of the correlation value of the quadrature component for the M-ary codes with respect to a first path and a second path;
combining each sum for each M-ary code for the first path with corresponding sum for the second path;
selecting a maximum sum among the combined sums for the M-aray codes and providing phase information corresponding to the maximum sum based on corresponding correlation values as the reference phase to coherent detection unit.
11. The method according to claim 10, wherein the phase information is filtered by using moving average process before providing the he coherent unit.
12. The method according to claim 10, wherein the phase information is filtered by using primary linear interpolation filter before providing to he coherent unit.
13. The method according to claim 11, wherein the phase information is filtered by using primary linear interpolation filter before providing the he coherent unit and after filtering by the moving average process.
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 bolt comprising:
a main body including a head and a shaft; and
a spring pin including a base portion and an end portion,
wherein said shaft includes a portion of external thread and a hollow portion,
said head includes a top surface and a hole opened in said top surface,
said hole is connected to said hollow portion,
said base portion is arranged in said hollow potion to move along an axis of said main body,
said end portion is arranged in said hole to move along said axis,
said spring pin is energized toward a side of said head such that said end portion protrudes beyond said top surface, and
said end portion is electrically connected to said portion of external thread.
2. The bolt according to claim 1, wherein a portion of said hole is a hexagon hole, and
said portion of said hole is opened in said top surface.
3. The bolt according to claim 1, further comprising:
a set screw; and
a helical compression spring,
wherein said set screw is screwed in an opening portion of said hollow potion,
said opening portion is opened in a end of said shaft, and
said helical compression spring is arranged in said hollow portion between said base portion and said set screw.
4. A semiconductor manufacturing apparatus comprising:
a wafer holding device for holding a wafer;
an ion beam irradiating apparatus for irradiating ion beam to said wafer;
a support supporting said wafer holding device; and
a bolt tightening said wafer holding device to said support,
wherein said bolt includes a main body and a spring pin,
said main body includes a head and a shaft,
said shaft includes a portion of external thread and a hollow portion,
said spring pin includes a base portion and an end portion,
said head includes a top surface and a hole opened in said top surface,
said hole is connected to said hollow portion,
said base portion is arranged in said hollow potion to move along an axis of said main body,
said end portion is arranged in said hole to move along said axis,
said support includes a portion of internal thread in which said portion of external thread is screwed,
said wafer holding device includes a base having a supporting surface,
said supporting surface contacts to a back surface of said wafer,
said base includes a spot facing hole opened in said supporting surface and a shaft hole connecting said spot facing hole to said portion of internal thread,
said head is arranged in said spot facing hole,
said spring pin is energized toward a side of said head such that said end portion protrudes beyond said top surface,
said end portion is electrically connected to said portion of external thread, and
said support is grounded.
5. The semiconductor manufacturing apparatus according to claim 4, wherein said support is a shaft of a motor.
6. The semiconductor manufacturing apparatus according to claim 5, wherein said wafer holding device includes a clamp ring pressing a peripheral portion of said wafer to said base.
7. The semiconductor manufacturing apparatus according to claim 4, wherein said wafer holding device includes a bipolar type electrostatic chuck.