[time-nuts] Frequency Distribution Design Basic Module attachment in pdf

Sat Aug 29 11:22:55 UTC 2015

May be some one cannot read the file .ods, so I have converted it to .pdf


Luciano


On Sat 29/08/15 11:24 , timeok at timeok.it wrote:

> Hi Charles,
> 
> On Fri 28/08/15 19:53 , Charles Steinmetz  wrote:
> 
> Charles wrote:
> 
> > I'm not aware of any instrument that needs a reference signal of more
> > than +13dBm (= 1Vrms), and most will happily accept much less than
> > that with no reduction in performance -- so I see no reason why a DA
> > with a maximum undistorted Po of +13dBm should be considered inadequate.
> 
> I didn't write that any instrument needs a reference signal of more than
> +13dBm (= 1Vrms) as you write, but a DA must be able to handle the signal
> levels of the standard on the market.
> I rely on facts and not words. I have measured the outputs level of some
> standard I have in my lab:
> 
> Nr 3 HP5065A +15dBm
> HP105B +13.62dBm
> Efratom MRT-L +13.60dBm
> Efratom MRT-H +14dBm
> HP Z3815 +9.40dBm
> 
> As you can see the HP GPS only is below + 13dBm.
> 
> If you need to power a devices that need 1A, you not buy a 1A max power
> supply but you want to ensure a margin and will buy one from A 1.5 or
> higher.Don't you think?
> 
> Charles wrote:
> 
> > What does seem inadequate for this century is the distortion
> > specification of your amplifier. -45dBc is pretty poor by today's
> > standards, and such high distortion generates additional phase noise
> > when the signal is AC-coupled and/or DC-restored, and when the client
> > instrument uses a zero-cross detector or other circuit that is
> > sensitive to the symmetry of the waveform. These days, it is not
> > difficult to build a 1-10MHz DA with distortion products more than
> > 65dB below a +13dBm output signal, either discrete or integrated.
> 
> Unfortunately,even in this case what you say does not conform to reality.
> I am attaching to this mail a comparison I made by taking from the web some
> characteristics about DA on the market or prototypes built by people far
> more expert than me.
> As you will also see, what we can consider top, made by NIST, has the same
> harmonic distortion of mine. With rare exceptions that should be evaluated
> more carefully, harmonic distortion is about 30dBc.
> 
> To get as you claim 65dBc, you must insert an output band pass filter or a
> low pass/notch filter which, as everyone knows, is phase sensitive as a
> function of temperature. For this reason, most of the DA currently on the
> market are broad band as the one I designed.
> 
> Best regards,
> 
> Luciano
> 
> P.S. : Please if you have found the web a DA admittedly broad band with
> features you write (-65dBc) can you give us the link?
> 
> On Fri 28/08/15 19:53 , Charles Steinmetz  wrote:
> 
> > Luciano wrote:
> >
> > >As for the amplifier the big job was finding the balance between the
> > >polarization parameters, harmonic distortion and output power.
> > >Many distribution amplifiers on the market have a Po max of + 13dBm
> > >and this limit does not seem appropriate for this century.
> >
> > I'm not aware of any instrument that needs a reference signal of more
> > than +13dBm (= 1Vrms), and most will happily accept much less than
> > that with no reduction in performance -- so I see no reason why a DA
> > with a maximum undistorted Po of +13dBm should be considered inadequate.
> >
> > What does seem inadequate for this century is the distortion
> > specification of your amplifier. -45dBc is pretty poor by today's
> > standards, and such high distortion generates additional phase noise
> > when the signal is AC-coupled and/or DC-restored, and when the client
> > instrument uses a zero-cross detector or other circuit that is
> > sensitive to the symmetry of the waveform. These days, it is not
> > difficult to build a 1-10MHz DA with distortion products more than
> > 65dB below a +13dBm output signal, either discrete or integrated.
> >
> > Best regards,
> >
> > Charles
> >
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