Computer Time Synchronization - NIST
equivalent device). This timer-counter generates an interrupt every 54.936 milliseconds, or about 18.2 times per second. The computer's BIOS (Basic Input Output System) contains a software routine that counts the interrupt requests and generates a time-of-day clock that can Computer Time Synchronization Michael Lombardi Time and Frequency Division
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• NIST offers to the public free software for using ACTS and NTS. ACTS does not require that you have an Internet Service Provider, but will require a long-distance telephone call through a modem to Boulder, Colorado. NTS does not require long-distance telephone calls, but does require that your computer be connected to the Internet.
Transport quantum logic gates for trapped ions D. Leibfried, E. Knill, C. Ospelkaus, and D. J. Wineland National Institute of Standards and Technology, 325 Broadway ...
We report reliable transport of 9Beþ ions through an ‘‘X junction’’ in a 2D trap array that includes a separate loading and reservoir zone. During transport the …
cavity temperature dependence The description of the temperature dependence of the resonance frequency is developed by starting with the phase accumulated in one round-trip of a cavity of length l and equating this to an integer multiple of 2 π:
It assists the working metrologist or calibration technician by describing the ... Figure 10. Portable shortwave radio receiver for reception of ... The standard unit of time interval is the second (s). Seconds can be accumulated to form longer …
The term frequency srabiliry encompasses the concepts of random noise, intended and incidental modulation, and any other fluctuations of the output frequency of a device. In general, frequency stability is the degree to which an oscillating source produces the same frequency value throughout a specified period of time.
hyperﬁne levels of the ground state of the cesium-133 atom. Frequency is the rate of a repetitive event. If T ... to detect parts of a time base cycle and have much higher resolution—1 ns resolution is commonplace, and 20 ps resolution is available. FIGURE 17.1 An …
Generally the interrupt ﬂag bit(s) must be cleared in software before re-enabling the global inter-rupt to avoid recursive interrupts. Once in the interrupt service routine the source(s) of the interrupt can be determined by polling the interrupt ﬂag bits. Individual interrupt ﬂag bits are set regardless of the status of their
of an Interrupt Request (IRQ) and the start of the respective Interrupt Service Routine (ISR). The interrupt latency is expressed in core clock cycles. 5.There is another exact definition-the number of clock cycles from the assertion of the interrupt request to the first ISR instruction executed, as shown in Figure 6.1. Conclusion
This minimizes the host’s interrupt service response for fast moving inputs. The device Port P outputs have 25 mA sink capabilities for directly driving LEDs while consuming low device current. One hardware pin (ADDR) can be used to program and vary the fixed I2C-bus address
interrupt can then be serviced by an interrupt service routine (ISR). Interrupt handling 5 Figure 1.3 Example of a simple interrupt system The interrupt handler is the routine that is executed when an interrupt occurs and an ISR is a routine that acts on …
C.4 FEATURES OF INTERRUPT SERVICE ROUTINES An interrupt service routine (ISR) is a special routine that is executed outside of the normal program flow. An ISR is invoked in response to a particular interrupt occurring at an undetermined time. Since an interrupt occurs at an unknown time, it cannot return a value directly to a program.
Controller with µP Interrupt The LTC®2954 is a pushbutton on/off controller that manages system power via a pushbutton interface. An enable output toggles system power while an interrupt output provides debounced pushbutton status. The inter-rupt output can be used in menu driven applications to request a system power-down. A power kill input ...