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True analog scopes
Fungus:
--- Quote from: 2N3055 on December 18, 2022, 12:15:19 pm ---
--- Quote from: Wallace Gasiewicz on December 18, 2022, 11:58:42 am ---When I switch from say, 30 MHx down to 1 KHz, I sometimes do not get a trace until I push the autoscope function.
On an analog scope all I had to do was to change the time base dial.
Not a big deal now that I know what to do.
--- End quote ---
I have no idea why is that.
--- End quote ---
Probably the trigger mode. It might be sat there waiting for a trigger.
tggzzz:
--- Quote from: 2N3055 on December 18, 2022, 12:15:19 pm ---
--- Quote from: Wallace Gasiewicz on December 18, 2022, 11:58:42 am ---Tautec:
When I switch from say, 30 MHx down to 1 KHz, I sometimes do not get a trace until I push the autoscope function.
On an analog scope all I had to do was to change the time base dial.
Not a big deal now that I know what to do.
--- End quote ---
...
I have no idea why is that. I assure you that modern low cost scopes from Siglent, Rigol and Micsig (or even noname brands) function perfectly and no such problems exist.
...
--- End quote ---
Given examples on this forum and elsewhere, "function perfectly" is a bold claim.
Some firmware upgrades trivially fix bugs like "The position of trigger level is wrong after changing the channel’s invert function.", "The reference waveform is wrong after storing the “CH1” wave of
reference and then changing the source of the reference to “D0” then press the channel setting of reference.", "The position of the trigger is wrong in high resolution mode.", "The value of variance measure item is wrong.", "The system crashes when the trigger level is set to 4 times the vertical scale"
Others bugfixes are/were less completely successful, for example where they involved noisy internal (PLL?) clock sources.
Note: I don't own one of the affected types and so have only peripheral knowledge of the topic based on a 30s google search and imperfectly remembered very long threads on this forum. The statements above are not definitive but do serve to raise questions about false expectations.
markone:
--- Quote from: tggzzz on December 18, 2022, 10:07:48 am ----snip
No: when I returned to real-time embedded electronics, it was still 8-bit micros programmed in C. No change in 35-40 years :( Well, smaller, faster, cheaper, but that's only a change in degree, not in kind. The main things that have changed are nanopower and ADC/DAC speed/resolution.
--- End quote ---
Which period are you referring to ?
Anyhow, interesting discussion that brings back to mind the transition era from vinyl to CD music listening in late 80s toward 90s (luckily now finished), funny to note that at the end digital compressed music and class D amplification won hands down after billions of discussions about spectral fidelity, 0.001% THD, jitter and so on.
The only people that I know that still own an analog scope are old hams (age > 60) that never get through the navigation of two levels menu system.
vk6zgo:
--- Quote from: Mechatrommer on December 18, 2022, 12:31:02 pm ---
--- Quote from: Wallace Gasiewicz on December 18, 2022, 11:58:42 am ---When I switch from say, 30 MHx down to 1 KHz, I sometimes do not get a trace until I push the autoscope function.
On an analog scope all I had to do was to change the time base dial.
Not a big deal now that I know what to do.
--- End quote ---
i suspect you are on "Normal" triggering mode (which is i suspect unavailable in CRO), you can change to "Auto" triggering mode and you still can see a flat horizontal line if signal is too slow. you can rest assured that we still have that time base dial on DSO to do the same...
--- End quote ---
CROs have both "Normal" & "Auto" trigger mode.
When I am looking at various points in a DUT, I normally let the 'scope "free run" in Auto.
Using DC coupling, with no vertical input voltage, I will then see a flat line at my selected zero position, .
This allows me to look at DC supply lines, as well as signal levels.
With 1v/div setting, if the line jumps up by around 5 divisions, I'm looking at a +5v supply, & so on.
If I then look at a point carrying signal, I will usually see that signal (unless it is very small), & can then adjust time/div, volts/div & trigger level to give me a stable display.
The early DSOs I played with didn't seem to have an equivalent to "free running", as without an input signal, they would not show a trace----it seems modern ones do.
I thought "roll" might do the trick, but touching the probe on a DC level displayed a transition from zero to that level, complete with contact bounce, (due to my shaky contact with the probe) overshoots, etc., which made it useless.
In most cases, it wasn't worth persevering with it, as there was a quite adequate CRO available.
Fungus:
--- Quote from: vk6zgo on December 18, 2022, 01:29:30 pm ---CROs have both "Normal" & "Auto" trigger mode.
When I am looking at various points in a DUT, I normally let the 'scope "free run" in Auto.
--- End quote ---
DSOs have the same, and a few more, eg. Single shot mode where you trigger once and it grabs the signal so you can look at it at in your own time, maybe even zoom in for a closer look... very useful, but CROs don't do it.
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