Comtech-ef-data MIDAS Version 4.X NMS Configuration Manuel d'utilisateur télécharger pdf (Page 89)

MIDAS 4.X NMS Configuration, Rev.6

Setup and Operation 2–61

• Doppler shift caused by satellite movement

• Stability of each clock (plesiochronous/Doppler operation only)

• Frame/Multiframe length of multiplexed data format

• Allowable time between clock slips

Doppler shift results from the movement of the satellite in space over a period

of one day in relation to the earth station. Doppler shift should not result in a

clock slip as the buffer will constantly fill and empty due to the cyclic nature of

the satellite motion.

Depending on the location of the earth station relative to the satellite, the

variation in propagation delay will typically be 1.15 ms (up to satellite and

back down). So, 2 ms will be sufficient for most commercial satellites.

Bits to Seconds:

1/DATA RATE * BITS = SECONDS

Seconds to Bits:

DATA RATE * SECONDS = BITS

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Comtech-ef-data MIDAS Version 4.X NMS Configuration Manuel d'utilisateur Page 89