The class 1 demodulator can be aided by increasing the carrier leakage to aid in this tracking. Even if this means decreasing the bit rate. The spin rate will probably be lower than this. The high spin rates, used for motor burns, will not be in use when the Class 1 facility is in use (after we release the spacecraft for use). I think Stacey wants "about 10 rpm" or so for sensors. I recall him saying this number.
I simply cannot believe we missed possibly the single biggest marketing tool we can have for SDX: the end of spin modulation on the SSB bandwidth signals. If the computational burden is actually low enough for this to be done to reduce the impact of the spin by a factor of 10-100 (power), it will be a big time win and a huge marketing tool for us to exploit.
Bob
n1al@cds1.net wrote:
What is the carrier tracking loop bandwidth? I'm kind of sruprised it can't compensate a maximum 1/4 Hz sinusoidal phase modulation. (The maximum spin rate is still spec'd at 15 rpm, right?)
Al N1AL
On Sep 27, 2006, at 1:41 PM, John B. Stephensen wrote:
The designer of the code to demodulate class 1 uplinks in the SDXneeds to determine whether spin modulation can be compensated for. The carrier tracking loop bandwidth may be close enough to the satellite spin rate that it can't be eliminated. I'm not sure how well open loop compensation would work as the phase pertubation will vary with the arrival angle of the signal and this could vary by as much as 30 degrees at MA32 and MA224.
73, John KD6OZH
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