Author Topic: FNIRSI-1013D "100MHz" tablet oscilloscope  (Read 33632 times)

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Offline Martin72

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #325 on: July 20, 2020, 08:21:43 pm »
Damn, good idea!

Tomorrow I´ll do it with the stb-3 .


Offline rhb

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #326 on: July 20, 2020, 10:22:44 pm »
I reran Ghidra specifying "ARM v5te little endian".  It generated an error message for an "aggressive one time" operation which I did not get when I used "ARM v4te little endian".  Without experienced guidance I
 have no idea what to make of it.

The noise level has gotten pretty high. I'm really not interested in Franklin Mint and such, so I think it's time to wander off.

If anyone actually does something please send me a heads up via PM.

Have Fun!
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Offline cliffyk

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #327 on: July 21, 2020, 02:56:40 am »
That measurement was with "alligator clips". I was interested in the bandwidth with the 1x probes. The 1x probes will have some capacitance that will lower the bandwidth.

If we have to use crocodile clips to get the most from this thing then there should be a way to get better results by adding a small amount of capacitance and limiting the bandwidth to something the system can handle.


The alligator clips represent the type of "probe" I am likely to employ in my use of this tool, as my primary use will be in troubleshooting contemporary electronic engine control system sensors and control devices in automobiles, motorcycles and almost any modern ICE powered equipment (even lawn mowers). Alligator clips, back-probe needles, and insulation piercing clips such as these:



On such machinery, and other than at board level within the "black box" engine and power-train control modules, there are mo pretty little test points to which one could connect a formal X1 or X10 oscilloscope probe--the best one can do is attempt to find something shiny to clip onto and when that fails you grab the proper color wire and punch a hole through the insulation (a spray of carburetor cleaner to degrease and a small drop of silicone sealer will plug it up when you're done).

For the most part the signal voltages are "highish", at 5 or 12 V typically; and signal frequencies max out at 1 to maybe 5 kHz. Consider that even with a 10 cylinder  4-stroke/cycle engine running 10,000 RPM (an unlikely find); spark, fueling, and monitor events occur only 50,000 times/minute; just 833 events per second.

Other uses such as monitoring voltage drops, start-up current draws and the like occur over multiples of minutes. Here are some traces i've captured over the years:

Testing an ignition coil (primary waveform at 0.054" and 15 mm plug gaps):


2003 Mustang GT triple-strike plug firing at idle (reduces NOx emissions):


1998 Mercedes SL500 IR keyless entry receiver output of keyfob "unlock" command:


1998 SL500 RF keyless entry receiver output, lock and unlock:


Only Mercedes knows why they felt both IR and RF controls were needed--they are incapable of doing anything normally, like lug bolts requiring an alignment tool to mount a wheel, instead of studs and nuts. Worst car I ever owned, gobs of fun to drive, just don't think too much about what plastic thing is going to deteriorate next,

2003 Mustang GT narrowband oxygen sensor output at 2000 RPM:


Suzuki Burgman 400 headlamp startup current w/a cheap Asian 5-pin DIN relay (captured using a MasTech clamp-on DC current probe):


Same with a quality NTE relay having reverse EMF protection:


Burgman 400 ignition ON current:


2009 Tacoma throttle position sensor, from closed to WOT:


2009 Tacoma, on-board 120 VAC inverter (so-called "modified sine wave" w/a 60W load):


My point is that there is a whole bunch of useful work one can do with an oscilloscope that does not involve single digit mV levels and MHz frequencies.

I think this silly little puppy may be just the ticket for much of that sort of work.

Did I mention it's as cute as a bugs ear?

--------------------------------------------
Not related to any of the above, but nonetheless a novel use of an oscilloscope in automotive diagnosis/repair, here's an analysis of an audio file I asked a fellow who was questioning the accuracy of his mustang Cobra's tachometer to send me. The FFT analysis revealed a predominate frequency (a loud exhaust note) of 154 Hz.

154 /4 [exhaust pulses per revolution for a V8] * 60 =  2310 RPM, just what his tach was reporting:


« Last Edit: July 21, 2020, 07:06:24 am by cliffyk »
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Online tautech

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #328 on: July 21, 2020, 03:02:12 am »
Cliff, can you select units of Amps in the channel input menu ?
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Offline cliffyk

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #329 on: July 21, 2020, 03:13:03 am »
Cliff, can you select units of Amps in the channel input menu ?

With my Lecroys you can select A as he unit label and scale the value display, but not with this little fella. However I'm pretty good at math and "make believe"...

 
« Last Edit: July 21, 2020, 06:52:54 am by cliffyk »
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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #330 on: July 21, 2020, 04:04:50 am »
Cliff, can you select units of Amps in the channel input menu ?

With my Lecroy's you can select A as he unit and scale the display, but not with this little fella. However I'm pretty good at math and "make believe"...
I quite understand and we needed to do maths on the fly with a CRO however most DSO's are able to display waveforms in the units of Amps.

Another FAIL for FNIRSI.  ::)

Thanks for checking.  :)
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Offline Fungus

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #331 on: July 21, 2020, 08:12:13 am »
Hi,

Done the meausure with the probe switching to 1x.
BW decreases to 17.8Mhz
Martin

 :-+

Not perfect but also not the disaster promised in the manual.

[attachimg=1]

Theoretically we could gain an extra 15Mhz in 1x mode by making a custom probe with just the right amount of capacitance, but... you'd only need that when you want 50mV/division.

The overlap in the Venn diagram isn't big enough to not bother, IMHO. People who want that would probably be using a real oscilloscope anyway.

« Last Edit: July 21, 2020, 08:21:09 am by Fungus »
 

Offline Fungus

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #332 on: July 21, 2020, 08:22:58 am »
I quite understand and we needed to do maths on the fly with a CRO however most DSO's are able to display waveforms in the units of Amps.

But the amount of menu-diving required simply isn't worth it.

Another FAIL for FNIRSI.  ::)

Yeah, total fail. They totally should have added a whole extra menu just for that.  Not. :palm:
« Last Edit: July 21, 2020, 08:37:59 am by Fungus »
 

Offline cliffyk

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #333 on: July 21, 2020, 08:43:53 am »
I quite understand and we needed to do maths on the fly with a CRO however most DSO's are able to display waveforms in the units of Amps.

But the amount of menu-diving required simply isn't worth it.


And all that does is change the label for use with a current probe--without a current probe an oscilloscope has no idea how much current a conductor is carrying.

Another FAIL for FNIRSI.  ::)

Yeah, total fail. They totally should have added a whole extra menu just for that.  :palm:

:palm: + 100, i'm with you on the face plant; And as I said above I'm pretty good at make believe...
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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #334 on: July 21, 2020, 08:52:52 am »
I quite understand and we needed to do maths on the fly with a CRO however most DSO's are able to display waveforms in the units of Amps.

But the amount of menu-diving required simply isn't worth it.

Another FAIL for FNIRSI.  ::)

Yeah, total fail. They totally should have added a whole extra menu just for that.  Not. :palm:
We need ask ourselves who might buy this $120 tablet instead of a proper DSO or for that matter a working CRO ?
At least an order of magnitude sensitivity better is available in all other scopes and totally without the apparent sensitivity to 10x probes.  :o
Yes older instruments do have their limitations too but not so for the most basic of measurements like these.

A buyers expectations of getting a somewhat capable instrument would not be met and for once on this forum I'd recommend the purchase of a CRO so not to be so disappointed. Yes I said that !  :palm:

Yet member bd139 picked up a mint condition TDS210 DSO yesterday for the same price as the topic of this thread of which I strongly suggest will be a much better investment.
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Offline cliffyk

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #335 on: July 21, 2020, 08:53:51 am »
Hi,

Done the meausure with the probe switching to 1x.
BW decreases to 17.8Mhz
Martin

 :-+

Not perfect but also not the disaster promised in the manual.

[attachimg=1]

Theoretically we could gain an extra 15Mhz in 1x mode by making a custom probe with just the right amount of capacitance, but... you'd only need that when you want 50mV/division.

The overlap in the Venn diagram isn't big enough to not bother, IMHO. People who want that would probably be using a real oscilloscope anyway.

That first statement in the manual's red-flagged  "Solemn reminder" section ("The bandwidth of the 1x probe file is 5 MHz,...") may be so with regard to the supplied probe in 1X mode, however I got out to 34 MHz at -3 dB, with alligator clips on the end of 16" of 50 Ω cable. In the morning I'm going to see what I can get with 3 ft of 18 ga. zip cord...
« Last Edit: July 21, 2020, 08:57:04 am by cliffyk »
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Offline Fungus

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #336 on: July 21, 2020, 09:01:21 am »
That first statement in the manual's red-flagged  "Solemn reminder" section ("The bandwidth of the 1x probe file is 5 MHz,...") may be so with regard to the supplied probe in 1X mode, however I got out to 34 MHz at -3 dB, with alligator clips on the end of 16" of 50 Ω cable.

It's all about capacitance.

You can get the same bandwidth by switching the probe to 10x mode, you just lose the 50mV range.

(because the x10 probe has a 10:1 voltage divider hidden inside it).

There'll be a compromise in between the two, which is what you're doing with your clips, but I suspect most people won't bother. It's nice to know it's there but the difference in bandwidth isn't huge (you're not getting the promised 100Mhz or anywhere close)
 

Offline tv84

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #337 on: July 21, 2020, 09:11:30 am »
Theoretically we could gain an extra 15Mhz in 1x mode by making a custom probe ...

I'm beginning to think the nickname of this puppy is "theoretically".  :-DD

Warning: I'm not bashing. I must do a comparison between my DSO138 and a MXR...  ::)
 

Offline cliffyk

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #338 on: July 21, 2020, 09:36:50 am »
That first statement in the manual's red-flagged  "Solemn reminder" section ("The bandwidth of the 1x probe file is 5 MHz,...") may be so with regard to the supplied probe in 1X mode, however I got out to 34 MHz at -3 dB, with alligator clips on the end of 16" of 50 Ω cable.

It's all about capacitance.

You can get the same bandwidth by switching the probe to 10x mode, you just lose the 50mV range.

(because the x10 probe has a 10:1 voltage divider hidden inside it).

There'll be a compromise in between the two, which is what you're doing with your clips, but I suspect most people won't bother. It's nice to know it's there but the difference in bandwidth isn't huge (you're not getting the promised 100Mhz or anywhere close)

I fully understand the theory of HF passive probes probes, however I just tested the supplied probe in x1 mode.

Here's a dose of empirical reality: 18.6 MHz @ -3 dB.

1 Mhz 1.01 Vrms:


18.6 Mhz 0.707 Vrms (-3 dB):

 
I don't think they ever tested the instrument, just threw together some specs based on theoretical capabilities.

I still like it, for my intended use it will do just what i need though i do wish it had triggered sweep at 20 ms/div and slower.

Have I mentioned that it's a cute as a bug's ear?
« Last Edit: July 21, 2020, 09:46:39 am by cliffyk »
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Offline tv84

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #339 on: July 21, 2020, 09:57:24 am »
This is another good example of compromise between € and capabilities.

Doing such a scope with a multimedia chip is another example of ingenuity and its developers surely did their best. Once again, I don't think it can be improved much more.

The specs that are presented by the vendor are executives/marketing "wishful thinking".

Once people here correctly characterize the performance envelope of this scope, I think it should be perfectly usable in non-demanding tasks by a great number of users.

Maybe its time for C-brands...
 
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Offline GeorgeOfTheJungle

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #340 on: July 21, 2020, 10:16:07 am »
Doing such a scope with a multimedia chip is another example of ingenuity and its developers surely did their best. Once again, I don't think it can be improved much more.

I wonder why did they put a front end so slow when the digitizer runs @ 200MSa/s? It's not a good fit. Perhaps the guy was better at digital than analog? It happened to Woz all the time.
« Last Edit: July 21, 2020, 10:39:38 am by GeorgeOfTheJungle »
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Offline tv84

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #341 on: July 21, 2020, 10:38:58 am »
I wonder why did they put a front end so slow when the digitizer runs @ 200MSa/s? It's not a good fit. Perhaps the guy was better at digital than analog? It happened to Woz all time.

There goes the neighborhood... you up the proc, you up the price. It's a fine balance. You have to put the limit somewhere.

Edit: What I meant is: you up the front end, and you'll be here asking for more sampling power...
« Last Edit: July 21, 2020, 10:42:11 am by tv84 »
 

Offline GeorgeOfTheJungle

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #342 on: July 21, 2020, 10:41:01 am »
There goes the neighborhood... you up the proc, you up the price. It's a fine balance. You have to put the limit somewhere.

Do you think it would have been so much more expensive?
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Offline tv84

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #343 on: July 21, 2020, 10:46:49 am »
Do you think it would have been so much more expensive?

I think so. When we are at this scale of "upscaling/modding", any small change in any part of the chain might force big € increments in the rest of the chain / total redesign. But, of course, IMHO.

I can easily imagine those meetings where this kind of things are discussed.
 

Offline GeorgeOfTheJungle

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #344 on: July 21, 2020, 11:08:40 am »
Do you think it would have been so much more expensive?

I think so. When we are at this scale of "upscaling/modding", any small change in any part of the chain might force big € increments in the rest of the chain / total redesign. But, of course, IMHO.

Look: https://mysku.ru/blog/aliexpress/80036.html#comment3580231

Quote
If R12 is reduced to 10-22 Ohm, the frequency response at the HF will become flat to 100 MHz.
If you increase C2, it will level out at the low frequency response.

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Offline rhb

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #345 on: July 21, 2020, 01:25:01 pm »
To provide good transient responses the input LP filter corner should be no more than 40-50% of Nyquist.

The steeper the filter skirt, the more the step response rings.

With a 100 MHz Nyquist, a 30-35 MHz LP corner is actually a good design choice.

Have Fun!
Reg

 

Offline Martin72

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #346 on: July 21, 2020, 02:29:52 pm »
Playing around with the stb-3 board :

[attachimg=1]

The demo board provides a variety of testsignals, ideal for doing a quick "overall" test on new scopes.
Sinewaves, squarewaves, pwm, runt, glitch, modulation, eres and several serial bus signals.
And inbetween it´s limitations, the scope performed well.
PWM signals are no problem:

[attachimg=2]

Runt and glitch pulses....Well, no.  ;)
Also it couldn´t display the AM signal (25Mhz carrierfrequency) proper, but the rest is not too bad, single/normal trigger works fine.
Showstopper is the minimum resolution of 500mV/div. in 10x mode and the missing of other triggerfunctions.
Interesting:
Frequency will only be measured when the trigger is in "auto" mode, in normal mode it doesn´t work.
Also you can´t "zoom" in after stop.

Continue playing with the board and scope...

Offline jemangedeslolos

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #347 on: July 21, 2020, 03:10:44 pm »
I don't understand why people are so shocked by the lies and the performance of this oscilloscope.
Who would be willing to take precision measurements on a device at this price ? It is the price of 2 x 100Mhz Siglent or Rigol probe  :-DD
Yes it is ridiculous to put forward this kind of performance and it should be banned but this is the case for 95% of cheap Chinese products.

if you have 150$ to put in an oscilloscope and it will be your one and only oscilloscope, go find another used device.
This oscilloscope is interesting only for these unique specifications : cheap, 7" touch screen, no boot time, long battery operation and small form factor.
Very useful in many cases.

tv84 is in the place so he will soon be able to unlock the serial bus decoding, the eye diagram and the zone triggering :-/O
 

Offline Martin72

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #348 on: July 21, 2020, 03:19:08 pm »
Quote
I don't understand why people are so shocked by the lies and the performance of this oscilloscope.

I´m not shocked about, I´m positively surprised. ;)

Offline UniSoft

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #349 on: July 21, 2020, 03:35:03 pm »
I don't understand why people are so shocked by the lies and the performance of this oscilloscope.
if you have 150$...
I'm not shocked!
Actual price is 100$ (on taobao.com in China, price is 699 RMB = ~100$), this is how much I paid...
Do you know any alternative for the same price?  :)
 


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