[time-nuts] f-multipliers from VHF to 10 GHz

[jimlux]

On 5/15/20 2:14 PM, Gerhard Hoffmann wrote:
> No, no, no, it's not that bad :-)  I should not post here in the middle 
> of the night. Sorry to cause that confusion.
> 
> Minimum  is -90 dBc @ 50 Hz, or let's say @100 Hz @ 10 GHz.
> that would equal -110 dBc at 1 GHz,   or -130 dBc @100 MHz, BTDT.


That's much easier.

Use one of the single chip synthesizers - they can probably do just what 
you want, with adequate performance.
> 
> The question was really only about a _simple_ multiplier chain. The
> style used in ham radio 10 GHz transverters has too many stages,
> GaAS-Fets with 1/f and pipe cap filters. Too complicated.

Yes, that would be an ordeal, and is completely unnecessary today.



> 
> Macom still make a SRD diode, but probably it is easiest to phaselock
> a ceramic puck or an on-chip VCO to a 100+ MHz crystal. The offset-
> mixing removes the need for a low reference frequency or fractional
> voodoo.
> o  

Trivially easy to lock the onchip VCO to a 10 or 100 MHz oscillator. 
These days, dividing down from 10GHz isn't a chore, like it was 15 years 
ago.

SRDs are a pain, they need huge drive power (100mW?) to work well, as do 
the Sampling Phase Detector/ harmonic mixer equivalents. It's hard to 
get a real low noise +20dBm signal . You'll spend as much time on that 
as the other stuff.

Sampling phase detector and DRO from 2004
https://tmo.jpl.nasa.gov/progress_report/42-156/156C.pdf

GaAs and PLL from 2006
https://tmo.jpl.nasa.gov/progress_report/42-166/166A.pdf


You can probably do it with an off the shelf eval board.