May be some one cannot read the file .ods, so I have converted it to .pdf
Luciano On Sat 29/08/15 11:24 , [email protected] 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 > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] [1] > > and follow the instructions there. > > > > > > > > Links: > > ------ > > [1] > > > http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma > [2] > > ilman/listinfo/time-nuts > > > Message sent via Atmail Open - http://atmail.org/ [3] > > > > Links: > ------ > [1] > http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma > ilman/listinfo/time-nuts[2] > http://webmail.timeok.it/parse.php?redirect=http://webmail.timeok.it/parse. > php%3Fredirect%3Dhttps://www.febo.com/cgi-bin/ma[3] > http://webmail.timeok.it/parse.php?redirect=http://atmail.org/ > > Message sent via Atmail Open - http://atmail.org/
comparative table.pdf
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