1. A frequency shift keying (FSK) modulator comprises:
a phase-locked loop operably coupled to generate a first oscillation from a reference oscillation;
a frequency divider module operably coupled to divide the first oscillation to produce a second oscillation;
an image-rejection mixer operably coupled to mix the second oscillation with a low intermediate oscillation data signal to produce a mixed data signal; and
a summing module operably coupled to sum the mixed data signal with the first oscillation to produce an FSK modulated signal.
2. The FSK modulator of claim 1, wherein the frequency of the first oscillation is twice the frequency of the second oscillation.
3. The FSK modulator of claim 1, wherein the frequency divider module is a divide by n module, where n is a positive whole number.
4. The FSK modulator of claim 3, wherein n=2.
5. A method for frequency shift keying (FSK) modulation, the method comprises:
generating a first oscillation;
dividing the first oscillation by a divider value to produce a second oscillation;
image-rejection mixing the second oscillation with a low intermediate frequency (IF) FSK modulated data signal to produce a mixed data signal; and
summing the mixed data signal with the first oscillation to produce an FSK modulated signal.
6. The method of claim 5, wherein the first oscillation is a 1600 MHz oscillation and wherein the second oscillation is an 800 MHz oscillation.
7. The method of claim 5, wherein dividing comprises dividing by n, where n is a positive whole number.
8. The method of claim 7, wherein n=2.
9. An apparatus for frequency shift keying (FSK) modulation, the apparatus comprises:
a processing module; and
a memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to:
generate a first oscillation;
divide the first oscillation to produce a second oscillation;
image-rejection mix the second oscillation with a low intermediate oscillation data signal to produce a mixed data signal; and
sum the mixed data signal with the first oscillation to produce an FSK modulated signal.
10. The apparatus of claim 9, wherein the frequency of the first oscillation is twice the frequency of the second oscillation.
11. The apparatus of claim 9, wherein dividing comprises dividing by n, where n is a positive whole number.
12. The apparatus of claim 9, wherein n=2.
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 X-ray imaging system for imaging an object comprising:
a vacuum bell for creating a vacuum envelope in an X-ray source;
an X-ray radiation-permeable window configured to emit X-ray radiation from a plurality of spots;
a collimator located between said X-ray source and said object for projecting said X-ray radiation through said object;
an X-ray detector for measuring amount of said X-ray radiation passing through said object and striking said detector;
a second vacuum bell in contact with said vacuum bell for creating a second vacuum envelope in a second X-ray source; and
a second X-ray radiation-permeable window configured to emit X-ray radiation from a second plurality of spots.
2. The X-ray imaging system of claim 1 wherein said X-ray radiation-permeable window and said second X-ray radiation-permeable window are in contact with each other.
3. The X-ray imaging system of claim 1 wherein said plurality of spots is located less than 1 cm from an edge of said window.
4. The X-ray imaging system of claim 1 further comprising:
a bonded connection between said window and said vacuum bell.
5. The X-ray imaging system of claim 4 wherein said bonded connection is a brazed bond.
6. The X-ray imaging system of claim 4 wherein said bonded connection is an electron beam weld.
7. A computed tomography X-ray imaging system for imaging an object comprising:
a plurality of stationary X-ray sources forming a ring for producing X-ray radiation;
a rotating X-ray detector positioned within said ring for measuring amount of said X-ray radiation passing through said object and striking said detector;
a stationary collimator located between said plurality of X-ray sources and said object;
a rotating collimator located between said plurality of X-ray sources and said object with a plurality of slots.
8. The computed tomography X-ray imaging system of claim 7 wherein said stationary collimator further comprises at least ten slots.
9. The computed tomography X-ray imaging system of claim 7 wherein said stationary collimator further comprises between 10 and 50 slots.
10. The computed tomography X-ray imaging system of claim 7 wherein said rotating slot collimator spans an arc between 60 and 160 degrees.
11. The computed tomography X-ray imaging system of claim 7 wherein said stationary collimator further comprises metal rings.
12. The computed tomography X-ray imaging system of claim 7 further comprising:
cooling water coupled to an X-ray target for removing heat generated by said X-ray target.
13. The computed tomography X-ray imaging system of claim 7 wherein said stationary collimator further comprises at least ten slots perpendicular to said plurality of slots.
14. The computed tomography X-ray imaging system of claim 7 further comprising a sensor for monitoring velocity of said rotating collimator.
15. The computed tomography X-ray imaging system of claim 7 wherein said plurality of X-ray sources operate at full power for at least one hour.
16. A method of aligning an X-ray beam in an X-ray imaging system comprising:
establishing a position of said X-ray beam with respect to a moving collimator at a plurality of time points;
navigating said X-ray beam to a calculated position of a hole in said collimator; and
correcting alignment of said X-ray beam based on location of said X-ray beam on said detector.
17. The method of claim 16 further comprising:
aborting said X-ray beam if said X-ray beam is not aligned.
18. The method of claim 16 further comprising:
determining centroid position of said X-ray beam on said detector; and
comparing said centroid position with a calculated centroid position for said X-ray beam.
19. The method of claim 16 further comprising:
monitoring velocity of said collimator.
20. The method of claim 16 further comprising:
calculating position of said detector based on said velocity and an initial position of said collimator.