Tek 2400 cte calibration? HELP - Page 1
Forum section: electronics / testgear

author: kc9qvl
author_rank: Regular Contributor
timestamp: February 28, 2014, 03:24:02 am
content: Hi trying to do the last calibration step on my tektronix 2440 and am a bit lost. The service manual is a bit sparse with this step. On screen says (connect a 6 div step to channel 1 and 2 with 5x pad and dual input connector and center both channels. Set frequency to 100 khz and press execute.So what do i center and how and what does the 6 div step thing mean. I need spoon feeding here

author: kc9qvl
author_rank: Regular Contributor
timestamp: February 28, 2014, 03:53:40 am
content: I think might have gotten it. maybe

author: David Hess
author_rank: Super Contributor
timestamp: February 28, 2014, 06:11:25 am
content: This step calibrates out any delay offset between the vertical channels so you want to divide the signal from the pulse generator and apply it to both vertical inputs using identical length cables. Any full screen relatively fast step is sufficient for the internal measurement routines to accurately measure the channel to channel delay.

author: kc9qvl
author_rank: Regular Contributor
timestamp: February 28, 2014, 01:02:41 pm
content: I think I will have to redo this step. I went from function generator to tee at channel 1 then another cable to channel 2. Maybe build w2aew's pulse generator circuit.

author: David Hess
author_rank: Super Contributor
timestamp: February 28, 2014, 06:25:08 pm
content: The pulse does not need to be particularly clean or the fastest possible. I got by with the ~3.5ns transition time of the sync output from my function generator. The delay to each vertical input should be matched closely of course. The slower members of the 2440 series do not bother with this calibration step.

author: kc9qvl
author_rank: Regular Contributor
timestamp: February 28, 2014, 11:15:36 pm
content: Will have to use other scope to check the rise time on my hantek dds 3x25. Sync out might be fasterEdit.Sync out was fast enough and hooked up cables correctly this time. So its fully calibrated.

author: Simon Spiers
author_rank: Regular Contributor
timestamp: December 14, 2016, 10:06:30 pm
content: Sorry to drag this topic up again. I am attempting this same cal process on my 2440. I am using a fast square wave from R&S APN 62 but the calibration routine never ends. How long should it take?

author: David Hess
author_rank: Super Contributor
timestamp: December 15, 2016, 02:46:41 pm
content: Quote from: Simon Spiers on December 14, 2016, 10:06:30 pmIt just takes a few seconds. Maybe the pulse edge you are using is not fast enough? I used the sync output from my function generator which being a TTL output was less than 10 nanoseconds.

author: Simon Spiers
author_rank: Regular Contributor
timestamp: August 04, 2018, 11:01:11 am
content: Just to close this up. You do need a very fast rise and fall time from a pulse generator to get this cal to complete. It is also sensitive to scaling and positioning on the screen.

author: David Hess
author_rank: Super Contributor
timestamp: August 04, 2018, 01:54:29 pm
content: Quote from: Simon Spiers on August 04, 2018, 11:01:11 amThe first time I did it I used the sync output from my function generator which is driven by a TTL gate so it does not need to be that fast.