[time-nuts] ok, newbie questions

[Said Jackson]

I was thinking to tap-off the Ocxo itself with a small buffer and bypass all of the internal stuff. Will report on that later..

Sent from my iPad

On Nov 27, 2010, at 9:22, "W2HX" <w2hx at w2hx.com> wrote:

> I wonder if the 19.6608 isn't needed, if one could unsolder the logic
> divider chips and reduce noise?
> 
> 73 Eugene W2HX
> 
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Bruce Griffiths
> Sent: Saturday, November 27, 2010 12:44 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] ok, newbie questions
> 
> Those switch mode regulator modules under the finned heatsinks in the 
> Z3815A are likely responsible for most of the spurs.
> The ECL/CML logic dividers and the various ouputs like 19.6608MHz also 
> contribute.
> 
> Since the E1938A output is only +4dBm, its very easy to degrade the 
> phase noise in the buffer chain if one isnt careful.
> With careful design a discrete buffer amp phase noise floor below 
> -170dBc/Hz should be possible with a + 4dBm input.
> 
> Bruce
> 
> SAIDJACK at aol.com wrote:
>> Not necessarily so..
>> 
>> My HP Z3815A here (desktop unit) has horrible phase noise and massive
>> spurs. Really to cry over since I know what the internal OCXO (1938A type)
> is
>> capable of generating.
>> 
>> See the attached plot.
>> 
>> bye,
>> Said
>> 
>> 
>> In a message dated 11/26/2010 16:37:26 Pacific Standard Time,
>> GandalfG8 at aol.com writes:
>> 
>> So if I  want a really souped-up freq standard for my lab,  then I  should
>> concentrate on finding the best oxco I can (which may be   disciplined by
>> the
>> GPS or manually occasionally calibrated to GPS), and  use  the best power
>> supply I can find.  These seem to be what I  should  concentrate on rather
>> than more channels.
>> 
>> I do believe  that I read  some stuff on the internet that the HP GPS DO's
>> do
>> seem  to have very good  power supplies (or converters) which contribute
> to
>> low spurs. So it seems  the HP's do have a real advantage (not  just  the
>> name).
>> 
>> 
>> 
>> 
>> 
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.