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Title: |
US4392749:
Instrument for determining coincidence and elapse time between
independent sources of random sequential events
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Country: |
US United States of America
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Inventor: |
Clemmons, Jr., James I.; Newport News, VA
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High
Resolution
Low
Resolution
9 pages
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Assignee:
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The United States of America as represented by the
Administrator of the National Aeronautics and Space
Administration, Washington, DC
other patents from
UNITED STATES OF AMERICA, NATIONAL AERONAUTICS AND
SPACE ADMINISTRATION (approx. 4,167)
News,
Profiles, Stocks and More about this company
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Published / Filed: |
July 12, 1983 /
July 10, 1981
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Application Number: |
US1981000282191
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IPC Code: |
G04F 8/00; G04B 47/00;
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U.S. Class: |
Current: 368/118;
368/006; 368/009; 368/010; 368/119; 368/120; 968/844; 968/DIG.001;
Original: 368/118;
368/006; 368/009; 368/010; 368/119; 368/120;
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Field of Search: |
368/6,9,10,118,119,120 235/92 T
328/129 324/181,186,187
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Government Interest: |
ORIGIN OF THE
INVENTION
The invention
described herein was made by employees of the U.S. Government and
may be manufactured and used by or for the Government for
governmental purposes without the payment of any royalties thereon
or therefor.
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Priority Number: |
| July 10, 1981 |
US1981000282191 |
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Abstract: |
An instrument that receives pulses from a primary external
source and one or more secondary external sources and determines
when there is coincidence between the primary and one of the
secondary sources. The instrument generates a finite time window
(coincidence aperture) during which coincidence is defined to have
occurred. The time intervals between coincidence apertures in which
coincidences occur are measured.
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Attorney, Agent or Firm: |
Osborn, Howard J. ; Manning, John
R. ; King, William H. ;
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Primary / Assistant Examiners: |
Truhe, J. V.; Flower, Terrance
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INPADOC Legal Status: |
Show
legal status actions
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Family: |
None
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First Claim: |
What is claimed is:
1. An instrument
for determining coincidence between a primary external source of
pulses and one or more other external sources of pulses comprising:
- means receiving said primary external source of pulses for
generating a start pulse, a reset pulse and a coincidence aperture
pulse each time a primary external source pulse is received;
- means receiving said coincidence aperture pulse and the pulses
from said other external sources of pulses for producing a
coincidence pulse each time a pulse from said other external
sources of pulses coincides with said coincidence aperture pulse;
and
- means receiving said start pulses, said reset pulses and said
coincidence pulses for measuring the time intervals between
coincidences.
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Background / Summary: |
BACKGROUND OF THE INVENTION
The invention
relates generally to laser velocimetry and more specifically concerns
an instrument, useful in laser velocimetry, for determining
coincidence and elapse time between independent sources of random
sequential events.
A laser velocimeter, when used in wind
tunnel applications, can generate large amounts of data arriving
randomly at a high average rate. Advanced measurement concepts, such
as vectorial flow field analysis, and turbulence
power-spectral-density studies, cannot be undertaken unless additional
instrumentation is used. Current methods of processing laser
velocimeter data determine the velocity statistics of an independent
component of the flow field. These methods do not assure the
researcher that each data point is based upon multicomponent
measurements of each seeding particle. However, known, coincident,
multicomponent measurements of each seeding particle would permit the
statistical analysis of the flow velocity vectorial quantities of
magnitude and angle. The
measurement of power spectral density requires time dependent data;
therefore, the time interval between successive measured events must
be known. In practice, the autocovariance function is determined by
using the velocity data along with the interarrival time data in a
Fourier transform to obtain the power spectral density.
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