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Tektronix 1-3 GHz touch screen color DSO back in 1989 !
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snoopy:

--- Quote from: Wuerstchenhund on August 28, 2017, 10:26:53 am ---
--- Quote from: snoopy on August 28, 2017, 09:22:44 am ---Instavu and DPO is not an underwhelming product enhancement by any stretch of the imagination. No other scope at the time had the ability to catch glitches at the same rate as these Tek scopes.
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That's nonsense, a scope that uses dedicated triggers will if setup correctly find always a glitch on its first occurrrence, as it doesn't have to rely on failure-prone human eyes to identify the glitch.


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Well if you can't identify what the glitch is then how can you ever setup the trigger to catch them ? Just try every possible permutation or combination of triggers ? A normal scope may never show the glitches for days and one may assume that there is nothing wrong with the circuit at hand. Later Tek scopes had the ability to set off an audible alert and freeze the display when a glitch occurred ! You talk like Instavu has no value at all in diagnosing a problem with a circuit !! Perhaps you've never done any fault finding and this feature would not be of any use to you ?



Wuerstchenhund:

--- Quote from: snoopy on August 28, 2017, 11:06:31 am ---Well if you can't identify what the glitch is then how can you ever setup the trigger to catch them ? Just try every possible permutation or combination of triggers ?
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No, of course you're not trying every permutation. On older scopes (like some of the ones from the mid-'90s) you just setup an exclusion trigger with the parameters of the signal, and wait for the glitch to appear. Chain it with statistics and you can get a nice histogram of when each glitch occurred, which in a complex circuit should usually gives you an idea to narrow the cause of the glitch down.


--- Quote ---A normal scope may never show the glitches for days
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Yes, for glitches that have periods of 10's of minutes or even hours, in which case sitting in front of an InstaVu screen would be equally silly because all it does is showing that there's a glitch, and that only if you happen to see it (sometimes glitches can even be small enough for them to remain unrecognized by the operator), and if you see it you then have to re-capture again in snail mode and hope your slow Tek scope will capture it with its now vastly extended blind time.

Also, in your rabid praise of InstaVu you completely ignore that even this mode has a blind time, and is likely to miss the occurrence of a glitch. Which means that even if you spend half an hour looking at your signal in InstaVu without seeing a glitch doesn't mean there is none, it just means you can't say with certainty that there are glitches.

The only way to be sure are advanced triggers.


--- Quote ---Later Tek scopes had the ability to set off an audible alert and freeze the display when a glitch occurred
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Yes, in DPO mode, which is just a slightly improved version of InstaVu.


--- Quote ---You talk like Instavu has no value at all in diagnosing a problem with a circuit !! Perhaps you've never done any fault finding and this feature would not be of any use to you ?
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I never said InstaVu has no value, I said it provides the same value like an analog scope which even back in 1995 was pretty limited. It's all great that InstaVu and DPO can achieve high waveform rates but the point you (and Tek, obviously) miss is that for a digital scope just emulating an analog scope isn't enough.

Ever wondered why even modern high-end scopes often only have waveform update rates in the thousands or 10k's per second? Exactly, because high update rates become pretty meaningless when you have a set of advanced triggers and analysis functions that can find pretty much any problem in any signal you want. Even on non-repetitive signals (try to find glitches on a non-repetitive signal with InstaVu, good luck!).

The point I was making (and on which you jumped off with your InstaVu fanboisim) is the same as the one the former Tek guy John Addis Steve Ditter was making, which is that Tek has been (and still is) living in their own world without considering what the competition does and what customers actually want. Again, if the aim was to make a digital scope that feels and can be used exactly like an analog scope then Tek was indeed very successful. But that's not what customers wanted, which was taking advantage of the possibilities that digitizing an analog signal brings, and which have been offered by HPAK and especially LeCroy (which for DSOs is pretty much what Tek has been for analog scopes). And this mindset can still be seen in Tek's latest products, which I find very unfortunate as I'd really like to see them stepping up and becoming a noteworthy competitor once again.
Leo Bodnar:

--- Quote from: David Hess on August 27, 2017, 04:44:50 am ---The 11K and SD specifications all say 200 kS/s maximum.  I think the chief limit in these single sampling gate designs is the operating life of the avalanche pulse generator.

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I came to conclusion that SD sampler heads don't use avalanche effect generators.
They do have SRD and clipping line sampling setup carried over from S series but SRD is excited by complimentary BJT pair in an arrangement that looks like a multivibrator.
I am not certain if SRD has stress limit when it reverse-conducts but it is certainly not well thermally connected to anything - it just hangs on its beam leads between two capacitors.
Perhaps, the sampling rate limit is enforced by maximum rate of TDR pulsers or some recovery processes in the mainframe.  11700 is so complex, it's hard to say for certain.

Leo
edavid:

--- Quote from: Wuerstchenhund on August 28, 2017, 01:12:29 pm ---The point I was making (and on which you jumped off with your InstaVu fanboisim) is the same as the one the former Tek guy John Addis was making, which is that Tek has been (and still is) living in their own world without considering what the competition does and what customers actually want.

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You misread that, it's Steve Ditter who is the 11K series hater.  John Addis is more positive.
Wuerstchenhund:

--- Quote from: edavid on August 28, 2017, 02:43:40 pm ---
--- Quote from: Wuerstchenhund on August 28, 2017, 01:12:29 pm ---The point I was making (and on which you jumped off with your InstaVu fanboisim) is the same as the one the former Tek guy John Addis was making, which is that Tek has been (and still is) living in their own world without considering what the competition does and what customers actually want.

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You misread that, it's Steve Ditter who is the 11K series hater.  John Addis is more positive.

--- End quote ---

My bad, thanks for the correction. Posting updated.
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