[time-nuts] low power, but quiet, oscillators

[Bob Camp]

HI

> On Feb 6, 2017, at 6:36 PM, jimlux <jimlux at earthlink.net> wrote:
> 
> On 2/6/17 2:37 PM, Bob Camp wrote:
>> Hi
>> 
>> One of the most basic reasons for putting out > +20 dbm is that you
>> had a spec of -195 dbc / Hz for the noise floor :)
>> 
>> Some of these specs *are* a bit mutually exclusive.
> 
> Sure.. And to be honest, I'm not sure that some of the folks coming up with paper requirements for these speculative low power transmitters are aware of that.  They take dBc values from 1 Watt transmitters and assume you can meet that with your 1 mW transmitter.
> 
> 
> 
> Then again couldn't you cool your oscillator.. that gets the T part of the kT down lower <grin>
> 
> Cool that puppy down to <1K and get 25dB noise improvement, eh?

Sounds like a low cost solution :)

The other proposed solution is to source the signal out of a zero ohm source. It’s not clear
which one actually costs less.

Bob

> 
> 
> 
>> 
>> Bob
>> 
>>> On Feb 6, 2017, at 3:19 PM, jimlux <jimlux at earthlink.net> wrote:
>>> 
>>> We're always looking for low DC power, but quiet (close in), oscillators for spaceflight applications, particularly as the spacecraft get smaller.
>>> 
>>> I was intrigued by the paper Ulrich posted which actually called out a "mW RF out for mW DC in" as part of their FoM.
>>> 
>>> Is there a list somewhere of what sort of DC/RF efficiencies are possible/typical.  In particular, I'm interested in topologies/designs that put out low powers.. (1 mW or less).  There's lots of designs that put out a convenient +10dBm or +13dBm or 3.3V CMOS square wave or whatever.. but sometimes, you only need to radiate a few mW  (I would think the low power Bluetooth/Zigbee/802.15xxxx folks have been thinking about this)
>>> 
>>> Jim
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> 
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