Alan: This requirement came up in the peer review, and was imposed on the design.
It needs to become a system requirement. I've separately requested draft of such a list of requirements.
Thanks & 73, Jim
Alan Bloom wrote:
Is the 10 MHz reference a possible single point of failure? Has it been made a requirement that all subsystems fail gracefully if the 10 MHz reference disappears?
Alan N1AL@CDS1.NET
On Mon, 2007-04-09 at 20:06, Jim Sanford wrote:
Bill et al: The requirement for the 10MHz reference descends from the July 2004 meeting in Orlando. As far as I know, it was never thoroughly justified, it was stated and made sense at the time. Still does, to me, tho I could be convinced on a case basis that we might not need it.
73, jim wb4gcs@amsat.org
Bill Ress wrote:
Some very good dialog has been taking place, lead by Juan Rivera as he heads up the prototype U Receiver build and test project.
Several very important questions have been raised but I'd like to address just one with this post.
I've volunteered to design and build the S2 Receiver and the C Transmitter and support microwave component efforts on the phased array for each. I am finishing efforts on a "prototype" single channel (assuming there might be several) S2 downconverter.
I fully recognize than "many" system design parameters have not yet been defined but I'm trying to get that "definition" effort moving along.
This is the first one I'd like to address.
In the coarse of designing the LO for the "prototype" S2 downconverter I have not been too concerned with use of the 10 MHz satellite clock. But I think it's time for "system" project guidelines to be developed for this issue since it can affect the design of all LO's. I have looked for guidance on the subject in Eaglepedia and have come up short. Point me in the right direction if it's there (and I just couldn't find it).
I hope I'm not rehashing old discussions (I've only been on the team since last October) but here are my questions:
- What is the reason for requiring all LO's to be locked to a 10 MHz
satellite system clock or are they?
- Have the performance specifications for the 10 MHz clock been
developed and what are they (in particular phase noise, frequency stability, susceptibility to digital hash, and power level available to each using subsystem - to name a few)?
My apologies for sending to the entire Eagle list but I'm not sure who has the responsibility for the clock.
Probably more questions to follow!!!
Regards...Bill - N6GHz
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle