Author Topic: LEA-6T disciplined SRS PRS10 Rb  (Read 3708 times)

0 Members and 2 Guests are viewing this topic.

Offline testpoint1

  • Frequent Contributor
  • **
  • Posts: 299
  • Country: us
Re: LEA-6T disciplined SRS PRS10 Rb
« Reply #25 on: April 17, 2020, 05:33:41 am »
I have an HP53131 too I can try.  I also have other references I can try vs. the BG7TBL but it's really handy so it's why I've been using it and it's on all the time.  I can also try my Thunderbolt E or one of 3 Rb free runners I've got as the external reference.  I should have the Pendulum by next weekend at the latest I think and it's pretty good all on it's own.  One thing I got that's kinda neat today is this to go with my SR620.
if your CNT-90 arrived, you will find the difference of your current clock, it is quite easy, I also have a HP 5071A want to sell (can lock, very accurate, but exists minor alarm).

Offline notfaded1

  • Frequent Contributor
  • **
  • Posts: 558
  • Country: us
Re: LEA-6T disciplined SRS PRS10 Rb
« Reply #26 on: April 17, 2020, 12:27:44 pm »
Your adev graph look very much like when I tried to gps discipline mine.  What happens if you disconnect it from GPS?
I'm going to try that next.  Also the SR620 configured with the configuration from the PRS10 manual seems to get me 5 digits time interval from the picosecond range when I tried it with fine configuration. It was bouncing back and forth slowly between .050000 Hz and -.050000 Hz.  It took it maybe 15 minutes to go back and forth.  I used this setup:

Set-up for an SR620
Described here is the set-up for an SR620 Time Interval Counter to make precision frequency
measurements. For a detailed description for the operation of the SR620, refer to the
instrument’s operation and service manual.
Four input connections:
The 10MHz reference frequency is connected to both the rear panel 10MHz input and to the
“A” (START) input. (Place the tee on the rear panel input.)
Connect the 10MHz from the DUT to the “B” (STOP) input.
Connect the 1kHz TTL square wave from “REF” output to gate “EXT” input BNC.
Four input setups:
From the front panel “CONFIG” menu, use “SET” to choose the “cAL” menu, then use
“SELECT” to select the “cLoc SourcE”. Use the arrow keys to set the clock source to
“rEAr”. This will allow the SR620 to use the 10MHz reference frequency which has been
applied to the rear panel 10MHz input as the timebase for all measurements.
Set the “EXT” gate input “LOGIC” to POS, “TERM” to 50Ω, and “LEVEL” to +1.0V. The
“TRIG” LED will go on when the “GATE/ARM” is setup properly.
Both “A” (START) and “B” (STOP) are AC coupled and terminated into 50Ω. The
“SLOPE” is set to “+”, and the “LEVEL” is turned full counter-clockwise to “AUTO” and
the “UHF” LED should be off. The “TRIG” LEDs will be on when the 10MHz sources are
“Coarse” Frequency Measurements
You should verify that the DUT is very close (within 0.1Hz) to 10MHz. To measure the
frequency, set “MODE” to “FREQ”, set “SOURCE” to “B”, set the “GATE/ARM” to 1s, and
set the “SAMPLE SIZE” to 1. Hold the “START” button down for a few seconds to start
continuous measurements. Set the display to “MEAN” to display the frequency of the
10MHz output from the DUT.
“Fine” Frequency Measurements
If the 10MHz from the DUT is within 0.1Hz of 10MHz, you may use the “fine” frequency
measurement technique to make measurements to a few parts in 10 to the 12th in a one second interval.
As explained above, the frequency offset between the reference and the DUT is inferred by
time-interval measurements between their zero-crossings.
To carry out these measurements: Set the “MODE” to “TIME”, select the “SOURCE” (of
START) to “A”, set the “GATE/ARM” mode to “+TIME” and “EXT”, and set the
“SAMPLE SIZE” to 1000. With the external gate triggered by the SR620’s 1kHz reference
output, the unit will display a new “MEAN” every second. If the DUT is adjusted so that the
mean of the time interval measurements changes by less than 10ps per second, then the DUT
is within 1 part of 10 to the 11th of the reference frequency.


Offline Theboel

  • Frequent Contributor
  • **
  • Posts: 278
  • Country: id
Re: LEA-6T disciplined SRS PRS10 Rb
« Reply #27 on: April 19, 2020, 08:44:38 am »

Here my Timelab result from 58503A vs 58503A.
because of nature of allan deviation You will see at beginning "promising world record result" and then My dream fade away  :palm: :palm: :palm: :palm:
GPSDO has so many parameter. 
« Last Edit: April 19, 2020, 08:51:07 am by Theboel »
The following users thanked this post: notfaded1

Offline stevenlvv

  • Newbie
  • Posts: 4
  • Country: cn
Re: LEA-6T disciplined SRS PRS10 Rb
« Reply #28 on: August 15, 2022, 06:59:00 am »
Could you confirm if the LEA-6T 1pps output (+3.3V output) works well with PRS10 1PPS_IN (need +5V input)? Thanks!

Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo