[Sls-ngu] RE: TC Bit Rate result from NGU Meeting

[Sank, Victor J. (GSFC-560.0)[MEI TECHNOLOGIES INC]]

Greg,
                Disagree with item 3.
In addition to the number being too strict compared to hardware capability, Doppler effects data rates just as it effects the carrier.  The factor is approximately v/c  which is of the order of 3x10^-5 for a typical space velocity (~ 30 ppm).  Hardware allows another order of magnitude of variability.  I would suggest the limit in item 3 be no more strict than 60 ppm.
Victor

From: Kazz, Greg J (313B) [mailto:greg.j.kazz at jpl.nasa.gov]
Sent: Wednesday, October 27, 2010 4:54 AM
To: Enrico.Vassallo at esa.int; Gian.Paolo.Calzolari at esa.int; sls-rfm at mailman.ccsds.org; sls-ngu at mailman.ccsds.org
Cc: Sank, Victor J. (GSFC-560.0)[MEI TECHNOLOGIES INC]
Subject: TC Bit Rate result from NGU Meeting

All,

The SLS-NGU WG came to consensus on the following issues regarding paragraph 2.2.8 of CCSDS 401-B-20 :


1.       Add 2048 Kbps rate to the existing table of data rates

2.       Missions are to attempt to achieve those telecommand rates within a frequency selection of plus or minus 0.1% of those rates

3.       The frequency stability that missions are to maintain during the pass for these rates is 1 * 10 E -6

4.       There is no need for any intermediate data rates

For further discussion at the joint meeting on Thursday AM.

Best regards,

Greg Kazz
Chairman SLS-NGU WG
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