Not sure what you are trying to say here? The waveform update rate isn't very important to digital scopes, despite the fact that some mainstream DSO makers try to get you to think it is the only number that matters - it is in their interest to promote their banner spec and get you to ignore so many important things that affect the usefulness of a DSO. .....
I think they should be called something else, because they do not work like an analogue scope, but I also realise that this is hoping for too much, the name DSO - we are stuck with it now. ......
As another thought about update rate... what is the response time of the LCD display, and how fast are its pixels updated? I don't have a model number or spec on the display LCD used int he Hantek/Tekway DSOs. If it is typically around 5mS pixel response time, the fastest update rate that can be seen is limited by the LCD response rate. 1/5mS =2000 changes black to white per second = 1000 hertz of a waveform. So, the fastest that any pixel can turn on and off, is 1000 times per second. It makes the very high waveform update rates that Tek and HP have been quoting pretty pointless I think.
Colin,
i miss to answer the part above ... so here we go.
the biggest advantage of analog osciloscope was that you could see the real waveform (generally spoken, because even with analog scope you
can measure bullshit) or beautifull random spikes on the phosphor ... the biggest disadvanted was the missing memory. Sure there are some combination
between both techs possible, but let stay on basics techs.
The biggest advantage of DSO is the memory, and vice versa to analog biggest disadvantage are the blind times between sample cycles
caused primarly due serial data processing (-> acq. data -> calculate waveform -> move data to µC -> display data ->).
Even if this process look like a "flow", it is combination of steps, with dead time between, which of course accumulate
to a very high total blind time.
The common misunderstanding is the waveform refresh rate, it does not have anything to do with actual display refresh,
from that point of view everything about 25-200frames/sec should be sufficient. It does have only something to do with the
time the DSO need to acquire, calculate and display the data, which is very slow on typical DSO due the serial process flow.
Same of course for DPOs , however they have significant differences to typical DSOs.
To have a real time digital scope (like a analog scope) we need to process 1000000 waveforms per second.
(Btw, the TDS754D is doing 80000wfrm/s, but only when single channel selected and 50point/frame,
with 5000point/frame and two channels enabled it less that 4000wfrm/s - not that far from HanTekway's 2500wfrm/s
in dual chan and 4000point/frame)
If you compare it to lower range Tektronix DPO with 5000 wfrm/s that's only 0.5% of what really happens and 99.5% blind time
(or 99.75 blind time for Tekway/Hantek ... or 99.92% for Rigol ... or 95% for Agilent DSOX 2k).
So what, is this data important ? Sure, if you have to capture glitches it is important - statement like "with Tekway you have 300%
more chance to capture glitch than with Rigol ..." funny heh, but it is actually truth.
If you have to watch endless sinus, a 20$ cheap toy-dso like Nano is good enough.
Tekway/Hantek DSOs are more like Tektronix DPOs, the data will be collected and rasterized - the resulting data accumulated and displayed
where spikes/gltiches with less occurrence will get displayed darker and more occurrence brighter to simulate phosphor.
Sure Tek DPOs are doing this job better having 256 stages (Tekway only 16), but it is the same idea.
(Note the difference - typical DSO is not rasterizing and accumulating data, so to see a glitch yuo have to wait
actually until the glitch happens within the sampling window - and then of course it will get display in same color/brightness as normal signal, so it might
, depends on glitch, misslead you)
As this process is (more or less -depends on the implementation) parallel on a DPO, the amount of captured data is higher than on typical DSO,
reducing blind times. The display refresh rate is a different story, lower range Tek DPO is doing display update with 30Hz
(where still the data will be collected, rasterized and moved to the display memory to get accumulated - and that with 5000 wfrm/sec).
Tekway is having 30/40/50Hz and auto (which is autoresponding refresh rate based on event occurance - it is actually good for XY, i pref. to use 50Hz)
display refresh rate (where still like on Tek the data will be collected, rasterized and moved to display controller to get accumulated with 2500 wfrm/sec).
As you own LeCory - for yrs LeCroy was not able to deliver scopes with high wfrm/s rate, they saw it only as Tektronix marketing gag (well, a drunken driver will always tell you others are responsible, he will be alway the best driver in the world) and tried to sell scopes via "big memory" marketing trick.
Sure, sufficient memory is important, but actually you can't sample with 1GSs for minutes (which you will need to see few khz glitch on Rigol/lower cost LeCroy). Luckily this changed, LeCroy is having today scopes with high wfrm/s rate (and sufficient memory) - but we talk now about
chinese products which are comparable to 5-10yrs old middle range scopes (Tek/LeCroy/HP) or even todays lower range Tek/LeCroy/Agilent scopes.
If you have enough money, you can get a good one digital scope which will be better than analog one, but honestly i prefer to drive a nice car
and work on lower/middle range equipment.