U.S. flag   An unofficial archive of your favorite United States government website
Dot gov

Official websites do not use .rip
We are an unofficial archive, replace .rip by .gov in the URL to access the official website. Access our document index here.


We are building a provable archive!
A lock (Dot gov) or https:// don't prove our archive is authentic, only that you securely accessed it. Note that we are working to fix that :)

This is an archive
(replace .gov by .rip)
A  |  B  |  C  |  D  |  E  |  F  |  G  |  H  |  I  |  J  |  K  |  L  |  M  |  N  |  O  |  P  |  Q  |  R  |  S  |  T  |  U  |  V  |  W  |  X  |  Y  |  Z

Delay (Path Delay)


  The [signal] delay between a transmitter and a receiver. Path delay is often the largest contributor to time transfer uncertainty. For example, consider a radio signal broadcast over a 1000 km path. Since radio signals travel at the speed of light (with a delay of about 3.3 ┬Ás/km), we can calibrate the 1000 km path by estimating the path delay as 3.3 ms and applying a 3.3 ms correction to our measurement. Sophisticated time transfer systems, such as GPS, automatically correct for path delay. The absolute path delay is not important to frequency transfer systems because on-time pulses are not required, but variations in path delay still limit the frequency uncertainty.
NISTIR 8323 from NIST T&F Glossary - Adapted