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REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol

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marmad:

--- Quote from: marmad on January 14, 2014, 09:09:01 pm ---
--- Quote from: Galaxyrise on January 14, 2014, 08:34:57 pm ---Ah, so you're saying "high" + "enter" means "enter the region above the high threshold" not "enter the region between the thresholds."  That explains why the manual calls it "Windows" (plural) trigger!  Yeah, everything does make sense with that meaning (except the "rising edge of the input" part of the manual.)  Thanks :) 

--- End quote ---

It definitively makes more sense when you think of it as 2 Windows with a dead-band - but the definitions are still un-intuitive. When I set a Trigger to happen on a Falling edge - I expect the trigger to take place ON the Falling edge. This doesn't work that way - so the names/terms should be different because they aren't working like every other Falling/Rising edge trigger.

Rigol is also using the same edge icons that they use with triggers that actually trigger on an edge - so not good. They should be different - or the icons should automatically invert depending on ENTER/EXIT selection.

--- End quote ---

Actually, instead of RISING EDGE, FALLING EDGE, and EITHER EDGE, those terms/icons should be TOPWIN and BTMWIN and BOTH - and then everything works as it should.

TOPWIN and ENTER triggers exactly when the signal enters the top window.
TOPWIN and EXIT triggers exactly when the signal exits the top window.
BTMWIN and ENTER triggers exactly when the signal enters the bottom window.
BTNWIN and EXIT triggers exactly when the signal exits the bottom window.

Galaxyrise:

--- Quote from: marmad on January 14, 2014, 09:33:03 pm ---Actually, instead of RISING EDGE, FALLING EDGE, and EITHER EDGE, those terms/icons should be TOPWIN and BTMWIN and BOTH - and then everything works as it should.

--- End quote ---

Yeah, that's why I switched from "rising" to "high".  I like your names better; matches the "WndType" setting name, too.

I've been thinking about it a bit more, and I wonder why the Windows Trigger even has a WndType setting? With a TOPWIN or BTMWIN setting, it's just an edge trigger, isn't it?  What's the use case where someone would rather set that up using a Windows Trigger?

marmad:

--- Quote from: Galaxyrise on January 14, 2014, 11:16:16 pm ---I've been thinking about it a bit more, and I wonder why the Windows Trigger even has a WndType setting? With a TOPWIN or BTMWIN setting, it's just an edge trigger, isn't it?  What's the use case where someone would rather set that up using a Windows Trigger?

--- End quote ---

Well, it's just the ability to have two different level settings instead of one. The DS2000 has 10 triggers which specify/allow 2 different levels, with 7 of those specifying/allowing a different channel for each level.

BTW, some people might not have noticed this, but there are 3 trigger types which AUTOMATICALLY use both channels (i.e. halving the sample rate) - whether you intentionally want to use both or not.

RUNT, WINDOWS, SLOPE: 2 levels - 1 possible channel can be specified as the trigger source.
DELAY: 2 levels - 2 channels ALWAYS used internally - but can be specified as the trigger source.
PATTERN, DURATION: 2 levels - 2 channels ALWAYS used internally - and can not be specified.
SETUP/HOLD, I2C, SPI, USB: 2 levels - 2 possible channels can be specified as the trigger source.

van-c:
Perhaps the term "window" refers to a window of time that opens up rather than a geometric window.  WndType determines when the window opens-- not the time at which the signal trigger occurs.  But the trigger can only occur after the window has opened.  Trigger Position determines exactly when the signal trigger actually occurs following the window opening.  Initially, the window is closed.

For example, for the rising-edge WndType, the window opens when the signal level passes above the high trigger level.  If ENTER trigger position is specified, the signal trigger occurs when the rising edge of the signal goes above the high level (which is as soon as the window opens);  if EXIT is specified, the signal trigger occurs after the window opens, but not until the signal passes below the upper level.

For the falling-edge WndType, the window opens when the signal level passes below the low trigger level.  If ENTER trigger position is specified, the signal trigger occurs when the falling edge of the signal goes below the low level (which is as soon as the window opens);  if EXIT is specified, the signal trigger occurs after the window opens, but not until the signal passes above the lower level.

The any-edge WndType and TIME trigger position follow similarly.

Does this make sense?

marmad:

--- Quote from: van-c on January 15, 2014, 04:19:23 am ---The any-edge WndType and TIME trigger position follow similarly.

Does this make sense?

--- End quote ---

Honestly, not too much. It seems like a convoluted way to describe or think about a trigger. Again, they are using the same icons they use with other triggers to show Edge triggering - and yet it's not triggering on those edges! My previous assertion that Rigol has just mislabeled/mistranslated the selections Rising Edge/Falling Edge seems to fit with two descriptions I Googled of Window Triggers:

Window trigger
This trigger detects the moment when the waveform enters or leaves a voltage range. This allows you to search for overvoltages and undervoltages at the same time. In Figure 10, a 5 volt power supply is monitored with thresholds of 4.5 and 5.5 volts. The window trigger would detect both the positive and negative excursions outside this range. The Direction control specifies whether the trigger operates when the signal enters the window, exits it, or both. The Threshold 1 and Threshold 2 controls define the upper and lower limits of the voltage window.

UppLev / LowLev also work as button names (instead of Rising Edge / Falling Edge) - or Over / Under.

Window triggering lets you define a window on your oscilloscope where the window boundaries are defined by low and high voltage thresholds and either "less than" or "greater than" time. You can then let the oscilloscope trigger when the waveform enters this window, exits this window, or when it is inside/outside of this window for too long or too short of time. This trigger allows you to filter out any noise that may occur on the bus so you can look at long term transient effects.

If Rigol wants to reproduce the Window trigger as specified by most other sources (which is a single defined Window), then the Enter / Exit button names need to be reversed - and the Rise / Fall names should be changed to one of the suggestions previously mentioned.

I'm betting this whole thing boils down to some Rigol employee misinterpreting/mistranslating something from English.

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