Hi!
Did anyone check if it was capable of 100Mhz? Or where its limit is?
Hi all.
I got one of these to test out. Results so far are OK-ish – i.e. it does work.
- My unit is way out on vertical accuracy, yielding around 212 mVpp for a 200 mVpp 1 kHz square wave. Specification is 2%, which seems optimistic, but 6% high is fairly poor.
- No way to store or restore setups, and fairly limited measurement options.
- I am not sure if it is set to a sinc mode or not – no setting for this.
- Waveform capture is two horizontal screens wide, so you can shift the window that much. No hold-off or other such niceties.
I have an oscilloscope calibrator here at work, so give some suggestions as to what I should verify and I will try to get it sorted.
Cool. I don't expect it to be perfect at this price point but is there anything you'd say was a deal breaker?
How's the touch screen? Good update rate? How easy it is to set horizontal/vertical scale? Does it crash and need rebooting?
Are you "This is OK...", or "What a pile of garbage!"?
That wouldn't worry me at all. "About 200mV" is fine.
(and yeah, 2% is never going to happen with an 8-bit ADC on a device like this)
Sooooo annoying if it doesn't power on to a known state (preferably the same as power-off).
It will be obvious if it doesn't have it: Zoom in on a rising edge and look for Gibbs phenomenon, ie. a sinc will show ringing before the signal starts to rise.
The main thing at this price point is being able to see wiggly lines on screen properly and not have any deal-breaking fails/annoyances.
I'd go to the extremes of horizontal scale and see how badly it aliases high/low frequencies. See if you can get it to display correct-looking waves with completely wrong frequencies.
How good is the FFT? I have a cheapo device with an awesome FFT (much better than the FFT on low end Rigols/Siglents).
FFT included in attachments. It seems viable for simple requirements. Update rate is fast.
Attachments:
Pic 1: 200 mVpp @ 1 kHz (centred)
Pic 2: 200 mVpp @ 100 kHz (centred)
Pic 3: 3 Vpp @ 50 kHz sine (centred) – horizontal jitter roughly ± 0.1 div
Pic 4: 3 Vpp @ 50 kHz sine (centred) – trigger shifted low
Pic 5: 3 Vpp @ 50 kHz sine (centred) – trigger shifted high
Pic 6 & 7: 3 Vpp @ 50 MHz sine (centred) – amplitude ~2.3<->2.5 Vpp
Pic 8: 3 Vpp @ 10 MHz sine (centred) – stable amplitude (becomes significantly unstable around 20 MHz)
Pic 9: 3 Vpp @ 10 Hz sine (centred) – roll mode (automatic - cannot be selected)
Pic 10: 3 Vpp @ 50 kHz sine (centred) – aliased signal (AUTO SET not used, but shows aliasing is possible)
Pic 11: 200 mVpp @ 1 kHz (centred) – FFT
Pic 12-14: 20 Vpp @ 1 kHz (centred) – FFT, shifting horizontal scale
Definitely something weird in the FFT.
How do you adjust the horizontal/vertical? Does it use gestures like pinch-zoom, etc.?
What are your thoughts about ease of use of the interface, especially compared to traditional knob and button layouts? Simpler? Confusing?
More or fewer steps to accomplish intent?
How useful is the manual for experienced? For noobs?
Would it be possible to test it with higher frequency square waves, e.g. 10-100MHz?
the manual appears to claim that you need to use the 10x probe setting to achieve the claimed bandwidth.
Jitter starts getting significant past 10 MHz for sine waves, so the triggering is a bit dubious.
the manual appears to claim that you need to use the 10x probe setting to achieve the claimed bandwidth.That's true on all 'scopes.
Jitter starts getting significant past 10 MHz for sine waves, so the triggering is a bit dubious.This is much more worrying. 10Mhz is in the "Arduino range".
the manual appears to claim that you need to use the 10x probe setting to achieve the claimed bandwidth.That's true on all 'scopes.
Not with an oscilloscope calibrator. Or at least I have not found this to ever be the case.
The bandwidth is determined using direct connection from an Active Head. (Usually 3 Vpp @ 50 kHz as reference level, so I did that here, but didn't bother to adjust for an accurate 3 Vpp reference indication because this isn't really a 'performance' instrument, so meh...)
So this instrument seems a bit odd, if it only functions correctly with the probe.Jitter starts getting significant past 10 MHz for sine waves, so the triggering is a bit dubious.This is much more worrying. 10Mhz is in the "Arduino range".There isn't a lot in the front end. A gradual deterioration in stability seems to occur, somewhere past 10 MHz for a sine wave. Because this starts at 50 mV/div, perhaps it would perform better with a higher amplitude than 3 Vpp.
Sounds like it's still a toy scope, not a serious instrument, and the bandwidth is still a lie. As expected.
So its amplitude rolloff is not consistent through the V/div ranges and BNC cable connection produces different results ?
So its amplitude rolloff is not consistent through the V/div ranges and BNC cable connection produces different results ?
It appears to be a weird hybrid / fast logger design to me, repurposed through software to give 'scope-like functionality.
My positive takes are: it is cheap, claimed to handle 400 Vpeak directly (yeah... I could check, but...), responsive UI, makes taking screen / waveform captures easy (but limited options if you want to do anything on the device), and it does yield a sensible(ish) trace up to 50 MHz+.
Negative: not really a handheld 'scope, IMO.
I think it is more of a "basic 'scope" / pretty inaccurate DMM hybrid. (And I suspect it's really a data logger.)
Should you buy it?
Well, will it do what you would want it for? Should be useful to quickly probe something before cranking up the real 'scope, as an alternative to the cheaper not-quite 'scopes, or for certain 'niche' uses. I intend on adding it to my gear for the Airsoft club, where it could be handy to check for battery/motor type faults where a DMM doesn't tell you enough.
Sounds like it's still a toy scope, not a serious instrument, and the bandwidth is still a lie. As expected.
Sounds like it's still a toy scope, not a serious instrument, and the bandwidth is still a lie. As expected.
Anybody could have told you that just from the price, no need to read the thread or get snobbish over it.
Every measuring/diagnostic device has its best uses and limitations and requires significant user familiarity with its best useage, quirks and anomalies.