[time-nuts] Re: Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input

[Wilko Bulte]

For those interested, Dave PA5DOF and your's truly are working to get the doubler implemented that Luciano has on his website. The first PCB prototype is in and has been built and works OK. Some minor tweaks/fixes  will be added to a V0.2 PCB. If there is interest I can share the Gerber files. 

The doubler is intended to be hooked up to an Efratom MRK-HLN 5MHz Rb. Our shack T&M equipment for the best part requires a 10MHz reference. 

Wilko

> On 29 Nov 2021, at 10:35, timeok at timeok.it wrote:
> 
> 
>   you can use this:
> 
>   http://www.timeok.it/wp-content/uploads/2015/08/high-performance-frequency-doublerv1-31.pdf
> 
>   Luciano P. S. Paramithiotti
>   timeok at timeok.it
>   www.timeok.it
> 
>   Da "Matt Huszagh" huszaghmatt at gmail.com
>   A time-nuts at lists.febo.com
>   Cc
>   Data Sun, 28 Nov 2021 19:29:58 -0800
>   Oggetto [time-nuts] Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input
>   Hi,
> 
>   I've got a 10 MHz distribution amplifier and am considering purchasing a
>   5 MHz reference. Most (not all) of my equipment accepts a 5 MHz
>   reference, but I'd like to be able to use the existing distribution
>   amplifier I have if possible. Therefore, I'm considering ways I might
>   generate a low-noise 10 MHz signal from the 5 MHz reference.
> 
>   An obvious way is to use a doubler. However, as I understand it, even an
>   ideal doubler will add 20log(2)=6 dB of phase noise to the 10 MHz
>   signal. It seems like a possibly more expensive, but lower noise way
>   would be to use a PLL with a divider that locks the divided 10 MHz
>   signal to the 5 MHz input. If the time constant of the loop filter is
>   set long enough, does this avoid the phase noise multiplication issue?
>   From what I've gathered, this is a technique HP used in some of their
>   gear. For example, the 8566 and 8340/1 lock a 100 MHz VCXO to an
>   external reference with a PLL.
> 
>   Any other thoughts on this?
>   Matt
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