Yet another "Help me choose oscillospe thread"

[tggzzz]

@tggzz

ISTR that some scopes will only decode what's visible on the screen, not everything that is captured in their memory. That would significantly reduce their usefulness in many situations.

In my experience the three critical features of a LA are clock speed, arm/trigger/filter, and memory depth. Better arm/trigger/filter means the memory doesn't have to be so deep. Ideally the LA's clock input will be driven by the UUT's clock.

If that the case then I will concentrate this budget on a good scope and later acquire a good logic analyzer, or? maybe I can go the hack route save couple of hundreds buck for the LA? That depends on what I end up buying

I am willing to suggest "ways of thinking" and possible alternatives. I am not willing to offer guidance as to what you should do since only you know all your objectives and tradeoffs.

Unless you already have suitable tools and already know how to use them, it usually pays dividends to consider the details of how you would go about making the measurements with the simplest possible tools plus a thoughtful implementation strategy.

Consider, for example, how you might use a very cheap LA ($10-20) which is little more than a clock plus memory. You would probably want to generate a signal saying "this is interesting", capture that plus the data, and then write your own software to post-process the captured data streams to extract only the "interesting" samples.

Or you might have software inside you UUT that blips an output when it detects a significant event, e.g. receipt or generation of a particular message.

In particular, learn to think in terms of FSMs where events cause transitions between states, and code your systems so that there is a direct representation of the states and events. Then use printf() statements and/or blip outputs when events or states or events-when-in-a-single-state occur.

And to annoy rstofer, I'll note my Tek 485 cost £25, but I did have to diagnose and recap the PSU That's my principal scope on a very small bench, or vertically alongside it. N.B.: I don't recommend you get a broken scope, unless fixing it is an end in itself!

[CustomEngineerer]

My comments on hacking were stated to be aimed at the entry level scopes, 1054Z in particular. From what I have read, admittedly not too much as they are out of my interest area, the higher cost/performance models are not necessarily as easy or approvingly hacked.

Rigol has never given any indication they either care or are concerned about the hacking of any of their scopes (or their other equipment that's also easily unlockable) regadless of cost/performance.

Yes, the DS1054Z is the only 'scope that's trivial to unlock. All the others require at least opening it up and using a JTAG programmer to modify some flash memory.

Sorry, but this is not true. The DS2000A series is as easily hackable as the DS1000Z. No JTAG, no opening scope, no modifying flash required. Also, like on the DS1000Z series, removing the hack (which leaves it completely undectable that it was ever used) is as easy as connecting to the scope through telnet, and sending a single command to reset the options to the default status.

Anyway, so this is what I'm planning so far

bandwidth: 200Mhz or higher (might be hacking a lower model is is easy enough and manufacturer doesn't care, and by that I mean that its been openly discussed here and manufacturer does care to take action)
Sampling Rate: no less than 500Msa/s when all channels active
# Channels: go with 2Ch (since 4Ch might be well out of my budget when taking into account sampling rate
Capture memory: not sure here, the more the better I guess

I'm not necessarily recommending the DS2000A scope, but it does seem to meet your new requirements. The DS2072A can be unlocked to 300MHz, has 1Gsa/s with both channels active and 56M capture memory. And unlike the DS1000Z it does decodes on the full sample memory, not just what's on screen. It's only 2 channel, but it's at least worth a look.

[luisr]

I'm not necessarily recommending the DS2000A scope, but it does seem to meet your new requirements. The DS2072A can be unlocked to 300MHz, has 1Gsa/s with both channels active and 56M capture memory. And unlike the DS1000Z it does decodes on the full sample memory, not just what's on screen. It's only 2 channel, but it's at least worth a look.

Yep, the Rigol DS2072A looks like a winner at this point... but I will have to dig more into the hacking thing.

[nctnico]

I'm not necessarily recommending the DS2000A scope, but it does seem to meet your new requirements. The DS2072A can be unlocked to 300MHz, has 1Gsa/s with both channels active and 56M capture memory. And unlike the DS1000Z it does decodes on the full sample memory, not just what's on screen. It's only 2 channel, but it's at least worth a look.

Is this recommendation from your own experience? AFAIK there are still quite a few unresolved issues in the firmware.