[time-nuts] Typical HP 5370B resolution ?

[Ulrich Bangert]

Mark,

given the fact that the measurement results of a 5370 are integer multiples
of 20 ps it is absolutely natural to see these steps in a phase plot, at
least if the input signals are not bad conditioned. I guess however the
question for the "typical" 5370 resolution was not whether these steps can
be seen or not but was after what the device offers as its effective
resolution. If you look at the AD plot of your Timelab measurements you will
see a much higher number than 2.0E-11 @ 1 s and the number that you see in
the AD plot should be considered the effective resolution because it
reflects the basic resolution as well as the trigger noise.

Best regards
Ulrich

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Mark Spencer
> Gesendet: Sonntag, 3. Marz 2013 18:49
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Typical HP 5370B resolution ?
> 
> 
> Thanks all for the suggestions.    
> 
> I am typically measuring 5 or 10 Mhz sine waves with levels 
> between 1 and 4 volts peak to peak into a 50 ohm load.
> 
> To expand on my first email  with suitable input signals I 
> can see the 20 ps resolution of the HP5370B on a "strip 
> chart" from time lab without any further effort.   So far 
> other than re seating the cards (which cured some lock up 
> issues on a few of them) I haven't really done any 
> maintenance to my HP5370's.   I'm also using a 5 Mhz BVA as 
> the reference oscillator for the HP5370B's in question which 
> seems to improve things vis a vis the internal 10811's.   At 
> some point when I have some more time I'll delve into the 
> reference oscillator matter in more detail as I'm a bit 
> surprised at this.
> 
> Magnus your suggestion to try attenuating the input signals 
> makes a lot sense and I will try this as different signal 
> levels do seem to make a difference.
> 
> Re the other recent post re cable issues I've also 
> encountered similar issues in the past and typically use 
> RG400 double shielded cables.   
> 
> Regards Mark S
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