[time-nuts] HP 53131A question

[Magnus Danielson]

iovane at inwind.it skrev:
> Hi all,
> 
> I'm planning to use a HP 53131A for phase measurements. 
> In a limit case, just to understand, suppose that I'm 
> reading, say, 100 degrees, and the next reading gives again 
> 100 degrees, but meanwhile the signal under test jumped 360 
> degrees. Is there any way to detect such a case? 

No. Not really. The counter makes a +/- TI measurement between channel A 
and B and also measures frequency on one of them. The individual count 
on the two channels is lost and thus the slip information. If you divide 
the signals down by say 10, then a signle cycle slip on the original 
signal would show up as a 36 degree shift in reading, while a 10 degree 
shift on the signal would be displayed as a 1 degree shift on reading.

The dividers would hold the state which you don't get directly. Some 
counters allow for simultaneous time-stamping and event counter 
recording of A and B channels. Those counters safe enought state to 
provide phase measurement (through time stamp) and slip difference 
(through event counters). You are interested in absolute phase, so that 
is what you want to do.

Cheers,
Magnus