[time-nuts] Chinese Scopes (was: Re: LORAN-C at MIT)

Hal Murray hmurray at megapathdsl.net
Mon Apr 16 18:03:33 UTC 2012


jfor at quikus.com said:
> Going through layer after layer of ever more obtuse menus is just not 'user
> friendly' to me. Maybe it is to the designers, because they are used to a
> 10,000+ character alphabet? 

How much of that is because you want to use fancy features that didn't even 
exist on older scopes?

Here is an example:  The switch from small/fast to big/slow memory is buried 
deep in a menu.  That's better than cluttering up the box with another button.


My Rigol DS1102E has 6 knobs, 17 dedicated push buttons, and 5 menu buttons.

One of the knobs is trigger level.  2 are horizontal scale and position.  2 
are vertical scale and position.  The 6th knob is for the current menu item.

The vertical knobs are shared by both input channels.  If you want to adjust 
the other channel you have to poke a button first.  Sure, I'd prefer 2 more 
knobs.  I can live with this.  It's not obvious how to fit in 2 more knobs if 
you did decide that was important.  Making the box an inch wider looks like 
the obvious way.

Glancing at my old Tek 465, the thing that I think I would miss most is the 
AC/DC coupling switch on the input.  I won't miss the Focus knob. :)

Neither scope has an optional 50 ohm terminator on the inputs.

-----------

I think there are 2 patterns for using a scope.  One is chasing a glitch.  
The other is collecting data.

When I'm chasing a glitch, I occasionally have to wander around in the menus. 
 Yes, it's annoying.  Part of the problem is that I sometimes don't remember 
how to get where I want to go so I make a few false starts.  Overall, it's 
not a lot more time than it took me to setup the hardware.  (I remember 
having to find a pair of coax cables with matched length.)

It would be fun to hack the firmware to record all the button/knob actions.

Once I have things setup, collecting more data is as simple as watching the 
screen or poking Enter on my PC.

----------

If you want to be critical, I see two weak areas.

One is the documentation and/or firmware for remote control.  It's good 
enough, at least if you are stubborn, but far from good.  (I haven't tried 
their software: no Windows boxes here.)


The other is the probes.  Good probes are still expensive.  The Rigol unit 
came with old big/clunky probes.  Why would anybody want a 1x/10x switch on 
their probe?  (I guess it might be interesting if you were working on small, 
slow signals, but I haven't done that in a long time.)

For probes, there is a knee in the curve somewhere around 200 MHz.  With a 
bit of care, you can get reasonable pictures up through 100 MHz.  Beyond 
that, you have to really pay attention and good/small probes help.  They also 
help with modern surface mount parts.


-- 
These are my opinions, not necessarily my employer's.  I hate spam.






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