System and method for precise absolute time event generation and capture

• US 20080016384A1
• Filed: 06/28/2007
• Published: 01/17/2008
• Est. Priority Date: 06/28/2006
• Status: Active Grant

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah Research Foundation (State of Utah)
• Inventors: Smith, Jeremy, Thomas, Stan, Wiencke, Lawrence, Thomas, Jason
• Granted Patent: US 7,975,160 B2
• Time in Patent Office: Days
• US Class Current: 713/375
• CPC Class Codes: G04F 10/00 Apparatus for measuring unknown time intervals by electric means

Abstract

The present invention is a system and method for precise absolute time event generation and capture. One embodiment of the present invention is a programmable hardware module for TTL pulse generation and capture in absolute time. The nominal accuracy of the programmable hardware module is 25 ns. The time reference is an on-board GPS (Global Positioning System) receiver. The hardware embodiment of the present invention can generate eight independently programmable outputs and capture the times on eight independently programmable inputs. An exemplary application for the present invention is triggering external light sources, and flash-lamp pumped lasers in particular, at specific times for calibration of cosmic-ray observatories. A software embodiment of the present invention is implemented in a Linux software device driver interface featuring an extensive set of user commands.

Claims

1. A system for precise absolute time event generation and capture, comprising:

a timing event generator for generating output timing events, wherein the output timing events may be a rising edge, a falling edge or any combination of a rising or falling edge;

a timing event receiver for sensing input timing events, wherein the input timing events may be a rising edge, a falling edge or any combination of a rising edge or falling edge;

a universal clock receiver for obtaining an absolute time clock signal; and

a processor in communication with the timing event generator, the timing event receiver and the universal clock receiver.

2. The system according to claim 1, wherein the timing event generator comprises pulse edge logic configured for generating the output timing events synchronized to the absolute time clock signal.

3. The system according to claim 1, wherein the timing event receiver comprises capture edge logic for receiving timing events synchronized to the absolute time clock.

4. The system according to claim 1, wherein the timing event generator is configured to independently generate the output timing events on a plurality of output channels.

5. The system according to claim 4, wherein the timing event generator is configured for generating the output timing events on eight output channels.

6. The system according to claim 1, wherein the timing event receiver is configured to independently receive input timing events on a plurality of input channels.

7. The system according to claim 6, wherein the timing event receiver is configured for receiving the input timing events on eight input channels.

8. The system according to claim 1, wherein timing event generation and capture comprises a timing measurement error of about 25 ns or less.

9. The system according to claim 1, wherein timing event generation and capture comprises a timing measurement error of about 12.5 ns or less.

10. The system according to claim 1, wherein the universal clock receiver is configured to provide a global positioning system (GPS) timing signal.

11. The system according to claim 1, wherein the universal clock receiver comprises a global positioning system (GPS) engine.

12. A method for capturing absolute timing events, comprising:

tracking absolute time;

capturing timing events;

time stamping the captured timing events relative to the absolute time; and

measuring elapsed time between the time stamped events.

13. The method according to claim 12, further comprising:

storing the elapsed time in memory.

14. The method according to claim 12, further comprising:

outputting the elapsed time for viewing on an output device.

15. The method according to claim 12, wherein tracking absolute time comprises receiving a global positioning system (GPS) time signal.

16. The method according to claim 12, wherein capturing timing events comprises capturing at least one of:

a rising edge, a falling edge, and a pulse.

17. A method for generating electronic timing events, comprising:

tracking absolute time;

defining a timing pulse sequence;

calibrating the defined timing pulse sequence to the absolute time; and

outputting the absolute time calibrated timing pulse sequence.

18. The method according to claim 17, wherein tracking absolute time comprises receiving a global positioning system (GPS) time signal.

19. The method according to claim 17, wherein defining a timing pulse sequence comprises defining an arbitrary sequence of rising and falling edges separated by preselected time periods.

20. The method according to claim 19, wherein calibrating the defined timing pulse sequence to the absolute time comprises synchronizing the arbitrary combination of rising and falling edges according to points in absolute time.

21. A system for precise absolute time event generation and capture, comprising:

an input device;

an output device;

a memory device;

an absolute time event generator and capture circuit; and

a processor in communication with the input device, the output device, the memory device and the absolute time event generator and capture circuit.

22. The system according to claim 21, further comprising a global positioning system (GPS) engine in communication with the absolute time event generator and capture circuit, the GPS engine configured to provide the system with an absolute time signal.

23. The system according to claim 21, wherein the memory device comprises computer-readable instructions for implementing a method for capturing absolute timing events.

24. The system according to claim 23, wherein the method for capturing absolute timing events comprises:

receiving the absolute time signal;

capturing timing events;

time stamping the captured timing events relative to the absolute time signal; and

measuring elapsed time between the time stamped events.

25. The system according to claim 21, wherein the memory device comprises computer-readable instructions for implementing a method for generating electronic timing events.

26. The system according to claim 25, wherein the method for generating electronic timing events comprises:

receiving the absolute time signal;

defining a timing pulse sequence;

calibrating the defined timing pulse sequence to the absolute time signal; and

outputting the absolute time calibrated timing pulse sequence.

27. A system for precise absolute time event generation and capture, comprising:

a circuit card, comprising;

an oscillator;

a global positioning system (GPS) engine for receiving a GPS clock;

a plurality of timing event inputs;

a plurality of timing event outputs;

a host bus interface; and

time event generation and capture logic in communication with the oscillator, the GPS engine, the plurality of timing event inputs and outputs and the host bus interface; and

a software device driver configured for controlling the circuit card through the host bus interface and time-stamping the plurality of timing event inputs and outputs with absolute time based on the GPS clock.

28. A system for calibrating cosmic ray detectors, the system comprising:

a plurality of lasers; and

a timing event generator in communication with the plurality of lasers, the timing event generator configured for generating a plurality of precisely timed digital trigger pulses to fire the plurality of lasers.

29. The system according to claim 28, wherein the plurality of lasers comprises a yttrium aluminum garnet (YAG) laser.

30. The system according to claim 28, wherein one of the plurality of precisely timed digital trigger pulses comprises a pulse configured for triggering a flash lamp.

31. The system according to claim 28, wherein one of the plurality of precisely timed digital trigger pulses comprises a pulse configured for triggering a high-speed optical switch on one of the plurality of lasers to cause light emission.

32. The system according to claim 31, wherein the high-speed optical switch comprises a Q-switch.