[time-nuts] Re: Ref out on Keysight 53230A

[Erik Kaashoek]

Jürgen

Is the period of the phase jumps of the ref out related to the frequency 
difference of the free running internal ref and the external supplied ref?
If so, this could imply the internal ref couples into the pll locking to 
the external ref and creates a periodically pull that causes the 
internal pll to jump.
If this is the case then the measurements done with the 53230A should 
also have such a phase jump when an external reference is supplied. Not 
sure if such a small phase jump would be visible on the 53230A.
On one of my counters the jump is only visible when I use a rather short 
(10 ms or lower) gate time but then it is very visible. With a gate time 
of 1 second the jump is totally invisible
If the measurements do not have such a  phase jump there is no harm done.
Erik.

On 24-1-2023 18:37, Bob Camp via time-nuts wrote:
> Hi
>
> Yup, that’s the sort of thing it does to the Ref Out.
>
> As long as you don’t use the Ref Out, it’s a very nice counter.
>
> Bob
>
>> On Jan 24, 2023, at 8:32 AM, Jürgen Appel via time-nuts <time-nuts at lists.febo.com> wrote:
>>
>> On Friday, 20 January 2023 01:54:25 CET Bob Camp via time-nuts wrote:
>>
>>> If you put the input and output into a Phase Station, you can see glitches
>> Never used the external output for something important before, but as the
>> devices were standing on the table, I wanted a record for the future:
>>
>> Setup: 10 MHz Reference to both "Ext Ref In" and Phase station, "Int Ref Out"
>> to DUT input of Phase station: Phase drifts rather slowly. As soon as I
>> connect some ~100MHz input to the 53230A, the "Int Ref Out" shows periodic
>> phase jumps. Turning the knob to increase the Gating time 0.1s->1s temporarily
>> disturbs the phase even more; the Glitch period seems unchanged though.
>>
>> Still like this counter though...
>>
>> Cheers,
>> 	Jürgen
>>
>>