Oscope trigger event capturing

[PrescottDan]

How can you measure a Signal Event waveform or a Non-Repetitive without using a storage O scope?

Where do you know where the trigger event started or began? when you use a non storage O scope?

When you measure waveform signals when the O-scope timebase setting at 50milliseconds, is this a very fast or very slow waveform? or can it be either?

What is a waveform or signal called when it only occurs or the switching transition happens only Once and doesn't repeat?

How can you measure a waveform or signal like this using a Non storage Oscope? can you use an Oscope that has a B timebase and B triggering? to put the triggered event on the B channel

 

[D.A.(Tony)Stewart]

It is called Manual trigger mode or One-shot trigger using Arm and trigger setup

But viewing fast waveforms can be difficult, but capturing the sweep may be all you need to know it triggered. In the past phospor storage CRT scopes were used with photo camera attachments or LOgic Analyzers with Analog channel. But for 50$ ( cheapo USB capture) or >250$ for an entry elvel DSO, there is no reason to not have a DSO.

There were once instruments called "Transient Signal Analyzers" which like most analog scopes used a delay line on the signal so the triggered signal could be viewed.

50ms is slow, 50 ns is fast. 0.5ns is very fast as below rise time

the name is transient signal or glitch. In power Engineering a HV transient inside switchgear or transformers is also called Partial Discharge or PD due to static charge buildup from AC going thru impure oil insulation and the result can be a slow discharge which generates Hydrogen, as shown below on a 300MHz DSO

As in any circumstance with EMI problems always use very short ground leads on scope probe. Use same ground reference, avoid stray current spikes and capacitively coupled spikes with good 10:1 probes or direct 1:1 coax using R pads to match impedance and reduce levels.

You calibrate the voltage threshold of the trigger and observe the waveform voltage to know where it triggered. They should match

 

[PrescottDan]

I'm using the Oscopes External trigger input and Channel#1 on the Oscope

I'm measuring the time duration from the Triggered event and the Switching transitions of the logic waveform on Channel#1 on the O scope

What is this called when you're measuring a time duration from the Triggered event to the switching transition?

There is a time delay from the triggered event from when the logic signal switches it's transition, but what is this called? what type of measurement?

 

[PrescottDan]

I have noticed when triggering on Channel#2 is you set the volts per divisions high it is harder for the O-scope to catch the triggering edge?

If the Triggered signal is an AC signal wave or a Logic square waveform it is harder for the O-scope to catch the triggering edge when the volts per divisions amplitude is higher , why is that?

It only works would the volts per division is set at a low amplitude for the triggering to work

 

[D.A.(Tony)Stewart]

The component specs may indicate Propagation Delay, Tp, for each polarity. Sometimes this is called Latency when measured in faster clock cycle delays. It is measured at the Logic Family threshold voltage for input and output. ( e.g. 1.3V for TTL and Vcc/2 for HCMOS )

First you want to make sure your test method uses calibrated probes using the square wave test waveform to give zero overshoot. There is a trim cap on 10:1 probes.

Second you want to ensure that your probes are low inductance, which means your grounds must be common connection , short in length and have flat braid wire or a ground plane. Your ground clip wire must be very short ( a few cm) for sub microsecond or ns measurements, if not then remove the clip and have two pins with signal and ground near the chip and use the pin centre and barrel ground for best signal capture. ( Tektronix has a spring barrel adapter to make short measurements between tip and gnd ring. )

Third, you want to calibrate your probe by measure the tip on your ground to make sure it is flat line with no common mode noise. It may be that you have a lot of AC hum on your ground from inductance or stray noise spikes.

Fourth and most important , you want your trigger source on the scope to be broadband ( not filtered )and DC coupled for stable trigger threshold. AC coupling and noise reject are useful too but if you have a clean signal, then trigger should be reliable. DC trigger should give stable pulses, unless the pulse has AC common mode hum wandering up and down.

If you can not trigger reliable square wave using the front panel test signal pin on the scope, then there is a fault with the scope setup as above ( e.g. missing ground connection or ground clip wire too long) or a problem with the scope.

Then you can get textbook looking waveforms.