time-interval measurement

Time-interval measurement

A determination of the duration between two instants of time (epochs). Time intervals are measured with high precision with a digital display counter. An electronic oscillator generates pulses; the count begins with a start signal and ends with a second signal. Two atomic clocks can be compared in epoch to 1 picosecond (1 ps = 10-12 s) by electronic interpolation. See Atomic clock, Oscilloscope

Rapid motions can be studied at short intervals by means of a large variety of high-speed cameras, including stroboscopic, rotating film-drum, rotating mirror, streak, and image converter cameras. An electronic streak camera can separate two pulses 1 ps apart.

Ultrashort laser pulses are used to study rapid processes caused by the interaction of photons with an atom or molecule. Pulses as short as three wavelengths of 620-nm light, with &tgr; = 6 femtoseconds (1 fs = 10-15 s), have been formed. See Laser, Optical pulses

Radioactive decay is used to measure long time intervals, to about 5 × 109 years, concerning human history, the Earth, and the solar system.

time-interval measurement

[′tīm ‚in·tər·vəl ‚mezh·ər·mənt]
(horology)
A process that consists either in calculating the duration between two known epochs, or in counting the repetitions of a recurring phenomenon from an arbitrary starting point, as with an electronic digital-reading counter, which counts the cycles of an oscillator.
References in periodicals archive ?
A method for continuous extreme-precision time-interval measurement // Automatic Control and Computer Sciences.
The analyzer's features include DC to 200 MHz, continuous-frequency and time-interval measurement (2 GHz optional)> up to 2 MHz measurement rate> autoscale, that is, one-button automatic setup and scaling of display> menu-driven operation> autmated functions for modulation and jitter analysis> 20 display updates/second> trigger on frequency or time-interval value or external trigger> hardware histograms of frequency and time-interval at 2 MHz measurement rate> 16K measurement memory, expandable to 64K> fully programmable through HP-IB> and one-button output of graphic display and setup to HP-IB printer.
The HP 53310A modulation-domain analyzer provides new levels of speed, ease of use and economy in an instrument that performs and graphically displays continuous-frequency and time-interval measurements with respect to time.

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