[time-nuts] RFG-RB Crystal Filter

Bob Camp lists at cq.nu
Sat Jan 16 21:19:45 UTC 2010


Hi

The answer I've heard for the Lucent-Whippany designed base stations using 15 MHz runs like this:

1) We started the program out and were told that 5, 10, or 15 MHz were all easy to get.
2) Somebody figured out that 15 MHz was better
	a) Because of a spur
	b) Because of a divide / multiply ratio
3) We designed it all up using a 15 MHz part
4) Then we priced it all out ....

You can pick your choice of 2a or 2b. I've heard it told each way. 

Assuming they started out with an OCXO and only went to a rubidium later, it would all make some sense. If they were planning on a rubidium all along then they got bad information up front. 

Bob


On Jan 16, 2010, at 3:52 PM, Hal Murray wrote:

> 
>> There's some magic on the other side of the filter to do the 10 to 15
>> MHz conversion.
> 
> I think I'm missing something interesting.  Why do they want 15 MHz?
> 
> Where are RFGs used?  Why do they want 15 MHz when the rest of the world 
> seems happy with 10 MHz?
> 
> -- 
> These are my opinions, not necessarily my employer's.  I hate spam.
> 
> 
> 
> 
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