Rohde RTB2002 / alternate trigger - Page 1
Forum section: electronics / testgear

author: Fran_PSR
author_rank: Newbie
timestamp: February 09, 2023, 08:27:24 am
content: Good morning everyone, I have a question regarding the handling of my Rohde RTB2002 oscilloscope.If I need to display two signals (CH1 and CH2), they are not an exact multiple of each other, for example 50Hz on CH1 and 60Hz on CH2, I can't find a way to stabilize the two signals since I only have the option of triggering CH1, CH2 or EXT . My dear old Hameg HM203-7 analog oscilloscope has an "alt" function that alternates triggering between CH1 and CH2. I asked Rohde technical support about this question and they tell me that my new oscilloscope does not have this function. How is it possible? Why does it have two channels if I can't visualize two signals? what am I doing wrong?Thank you very much and good day

author: nctnico
author_rank: Super Contributor
timestamp: February 09, 2023, 08:32:45 am
content: Unfortunately alternate triggering is a relatively rare function. And when using alternate triggering, the signals you get on screen are not related. As in: they didn't happen at the same time. What you could do is set the trigger hold-off to a large value like half a second. That slows down the triggering so you can see the shape of both signals but only one will be really stable.

author: 2N3055
author_rank: Super Contributor
timestamp: February 09, 2023, 08:48:36 am
content: Like Nico said, this function is very rare nowadays..I don't own RTB2000 so cannot check, but on Siglent scopes I have, you can achieve something similar with Pattern trigger.On them you can select to trigger on 2 analog channels with a logic function (AND or OR).That way scope will trigger when, for instance, both signals have a rising edge at the same time (actually within user defined time window). If signals are not correlated in frequency, there will be many moments where that is true.You can also experiment with OR, which in a way is alternate trigger. Here scope will trigger on any edge on any of channels ..If I remember correctly, RTB2000 should have similar trigger mode.Maybe try to experiment with that. Check manual for details..Best,

author: Fran_PSR
author_rank: Newbie
timestamp: February 09, 2023, 09:30:03 am
content: Thank you very much for the answers, indeed the alternative mode does not really show the relationship between the two signals but in my case it is useful for displaying frequency converters. I tried the logic trigger function but it doesn't work well. Rohde has improved the "reference" function for me, and if it works better but it does not reach the stability and ease of the alternate shot of the old Hameg. I don't have a critical need since for these cases I continue to use Hameg but I am very surprised that modern equipment does not have this... "I think I have stuck in the past...".Thank you all very much for this clarification.

author: egonotto
author_rank: Super Contributor
timestamp: February 09, 2023, 04:56:32 pm
content: Hello,perhaps "single" can help you.But if you want to see new images continuously, maybe a trigger source switching by a program would be possible.Marco Reps is measuring the noise of some ADR1000 with a MXO4. There he uses a program. That may perhaps be a suggestion:https://youtu.be/mmsBT3Fuggk?t=3030His Program:https://github.com/RPG-Engineering/RSscope_scriptsBest regardsegonotto