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Steve Conner

Fri Nov 06 2009, 10:35AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Could I have one of the FPGA boards? I have no idea what to do with it, but it would look great on the wall of our lab.

Wolfram

Fri Nov 06 2009, 12:23PM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

Do you have a picture of the FPGA boards showing all the chips on them? Are there any non-BGA FPGAs on any of the boards? In that case, I'm interested.

A.M.

Chris Russell

Fri Nov 06 2009, 03:11PM

... not Russel!
Registered Member #1 Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052

If you come across an OCXO that you're willing to part with, I'm definitely very interested.

Conundrum

Fri Nov 06 2009, 10:46PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

sure. if you want i can retrieve one of the damaged boards (a chip is cracked at one edge), or send an intact one.

whats your postal address?
regards, -A

Dave47

Sun Nov 08 2009, 05:41PM

Registered Member #84 Joined: Thu Feb 09 2006, 01:06PM
Location: Dallas, TX
Posts: 47

Dr. Slack wrote ...

It depends what you mean by low phase noise for the Vectron oscillator.

It's an OCXO (oven controlled XO), so it's likely to be the timing reference for the base-station. This will be super high stability, it's got to maintain +/- a gnat's if the external reference goes down, look up Stratum III for a typical holdover specification. However, it will not necessarily be supa dupa (just fairly good) at 20kHz or 10MHz offsets which would be needed for a quiet signal generator reference.

Anyhow, not to be sneezed at.

So, what do you consider super low phase noise? Here is one that looks similar:

and it can do -145 dbc/Hz at 1 KHz. Put a bandpass filter on it and you can fix any of the leftovers farther out (like at 10 MHz.)

To me, the bottom line is that this is (was) a basestation and was full of DACs and ADCs that require a low phase noise clock. Otherwise, they won't meet their datasheet typs for SNR and SFDR. That low phase noise clock was derived from this OCXO. Why put in a reference that is going to hinder the performance of all that silicon you are paying good money for.

If only we could read the number on it...

David

Dr. Slack

Sun Nov 08 2009, 08:51PM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

Why put in a reference that is going to hinder the performance of all that silicon you are paying good money for.

It's tad more complicated than that, but it would be OT to go into deep detail in this thread. It really depends on exactly how the reference is being used and what frequency it is, and what the jitter spec for the converters is. "Low noise" to comms people usually means something different than "low noise" to instrument people.

I wonder what frequency / part number it is?

Conundrum

Fri Nov 20 2009, 09:27PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

update:- the transmitter modules contain two 125W 2.3 GHz mosfets and two 15W, in what looks like a dual PA stage.

Any use?
-A

Proud Mary

Sat Nov 21 2009, 05:05AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Conundrum wrote ...

update:- the transmitter modules contain two 125W 2.3 GHz mosfets and two 15W, in what looks like a dual PA stage.

Any use?
-A

They sound great fun, and the case is worth a lot if you had to buy it. Even if you decide to toss it out, Andre, I'd cut out all the useful looking bits of aluminium stock as you'll surely need them soon.

S X

Conundrum

Sat Nov 21 2009, 11:46AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

hmm. thanks for the tips. I also just found a circa 2000 era dead LCD projector (the expensive hybrid on the mainboard went Tango Uniform) but the lenses, LCDs and dichros look OK.

the lens unit has motors for focus so this could be handy. Everything else including the lamp, dichro module (a bit dusty but repairable) and LCDs are surplus and can be sent for the cost of postage.

-A

Proud Mary

Sat Nov 21 2009, 03:44PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Conundrum wrote ...

hmm. thanks for the tips. I also just found a circa 2000 era dead LCD projector (the expensive hybrid on the mainboard went Tango Uniform) but the lenses, LCDs and dichros look OK.

Golly, well I'm sure you could do something with that, Andre, if not now, later. I have a bin called 'optical scrap' in which I put salvaged lenses and stuff, and I know it'll all come in handy one day - Stella

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