Author Topic: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review  (Read 4994 times)

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Offline Mr.B

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #25 on: July 14, 2020, 08:41:06 pm »
Just ordered one.
Should be handy for basic stuff, but the portability is the main reason for the purchase.
Now to see if it is hackable...
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Offline Martin72

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #26 on: July 14, 2020, 08:47:11 pm »
I must confess, although this thing is nothing more than a toy, it makes me curious.
After all, they got a support area on their Homepage.
Maybe, firmware updates will be avaible sometimes.

Offline iscle

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #27 on: July 15, 2020, 03:04:58 am »
I'm planning on rewriting the firmware, adding more features like I2C or UART decoding, and maybe even giving access to a Linux desktop!

I'd need access to the winbond SPI flash contents. That's where the firmware is stored (U-Boot, Linux Kernel and app). If anyone can dump it and post it, it would be great. If not, I will have to wait until I receive mine.

Thanks!
 
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Offline fkfaraz

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #28 on: July 15, 2020, 10:30:04 am »
hello @iscle

i did not have it but if I did I would certainly do that as I am also interested in a new firmware.
 

Offline iscle

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #29 on: July 15, 2020, 01:53:44 pm »
hello @iscle

i did not have it but if I did I would certainly do that as I am also interested in a new firmware.

My plan is to improve the UI by building a brand new one with Qt, and also providing more ways of controlling the FPGA (and the ADCs), being able to set the sampling rate and more. For that, the FPGA will need new code too, which I'm looking into (I only know a bit of VHDL when I did some university assignments three years ago).
 
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Offline Martin72

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #30 on: July 17, 2020, 09:59:49 pm »
Just for fun I´ve ordered one now, should arrive on monday.  ;)

Online tautech

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #31 on: July 18, 2020, 01:41:25 am »
Max sensitivity of 50mV/div is a crippling limitation.....at least 10x less sensitive than most other basic scopes.  ::)
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Offline snoopy

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #32 on: July 19, 2020, 01:49:20 am »
For those who want to turn off the auto triggering level in AUTO trig mode the setting is buried away in the system menu of all places. They should have put it in the trigger menu |O

cheers
« Last Edit: July 19, 2020, 01:57:55 am by snoopy »
 

Offline Fungus

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #33 on: July 20, 2020, 07:05:35 am »
For those who want to turn off the auto triggering level in AUTO trig mode the setting is buried away in the system menu of all places. They should have put it in the trigger menu |O

You only need to turn it off once.

Over in the other thread it's been noted that if you use a x1 probe then pretty much all the problems disappear due to the extra capacitance.  You're limited to about 30MHz, sure, but all the artifacts disappear.

I think it would be cool to find the optimum capacitance to maximize bandwidth, solder a capacitor of that size into the front end, go back to using x10 probes.

This simple mod would mean you can rely a lot more on what's being shown on screen being correct. Anybody up for doing it? (I don't have one of these yet, so...)

Maybe there's a 'hacking the Fnirsi Tablet Oscilloscope" video in this for Dave.
« Last Edit: July 20, 2020, 07:09:35 am by Fungus »
 

Offline Fungus

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #34 on: July 20, 2020, 07:07:07 am »
Max sensitivity of 50mV/div is a crippling limitation....

Not for an awful lot of scenarios, it isn't.


Yeah, we know, we should all buy Siglents instead.

 

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #35 on: July 20, 2020, 12:20:54 pm »
Max sensitivity of 50mV/div is a crippling limitation....

Not for an awful lot of scenarios, it isn't.


Yeah, we know, we should all buy Siglents instead.
FFS get real Fungus !
Put a 10x probe on the POS and you're limited to 500mV/div max sensitivity which in the real world (maybe not yours) is seriously limiting.
Really what planet are you on ?  :-//
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Offline Fungus

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #36 on: July 20, 2020, 02:28:27 pm »
FFS get real Fungus !
Put a 10x probe on the POS and you're limited to 500mV/div max sensitivity which in the real world (maybe not yours) is seriously limiting.
Really what planet are you on ?  :-//

Oh, I forgot about that. OK, 1x probes it is. :-)

Has anybody measured the -3db point with 1x probes? I can't find it in either of the threads.



 

Offline Martin72

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #37 on: July 20, 2020, 03:53:51 pm »
Can do it in the next hours.

Two threads parallel...which will "win"  8)

Offline Fungus

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #38 on: July 20, 2020, 04:17:59 pm »
Can do it in the next hours.

Two threads parallel...which will "win"  8)

The other thread is busy dumping the firmware...  :popcorn:
 

Offline 2N3055

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #39 on: July 20, 2020, 06:55:41 pm »
In 1x probes alone will have 5-10 MHz bandwidth.. Scope's bandwidth of 1X/10X probes is rated at 10x
So for best bandwidth you need to put probes in 10X..
 

Offline Fungus

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #40 on: July 20, 2020, 07:10:12 pm »
Can do it in the next hours.

Two threads parallel...which will "win"  8)

The other thread is busy dumping the firmware...  :popcorn:

Edit: No, they won. It's over 30Mhz.


No, scratch that. That measurement was with "alligator clips" so it won't have the capacitance of a 1x probe.
« Last Edit: July 20, 2020, 07:13:25 pm by Fungus »
 

Offline Fungus

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #41 on: July 21, 2020, 08:10:26 am »
Hopefully they will offer some firmware upgrades and allow the auto triggering level detection to be switched on or off. 

You mean this?

[attachimg=1]
 

Offline pplaninsky

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #42 on: July 26, 2020, 05:12:38 pm »
Is this usable to make floating measurements?
« Last Edit: July 26, 2020, 05:51:18 pm by pplaninsky »
 

Offline Fungus

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #43 on: July 26, 2020, 05:46:04 pm »
Is this usable to make floating measurements?

It only does floating measurements when it's on battery power.  :)
 

Offline pplaninsky

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #44 on: July 26, 2020, 05:52:09 pm »
Battery power should be OK, here is what I am having in mind.

In many old 20MHz CROs, there is electrostatic CRT and the cathode is driven at around -2KV DC, whereas a lot of the driving signals has differential voltage of 20 V DC or less.
Measuring that with an oscilloscope referenced to ground will produce a big bang or at best the GFCI will trigger.
A 2KV to ground (common mode range) differential probe is a rare and expensive device.
« Last Edit: July 26, 2020, 05:54:22 pm by pplaninsky »
 

Offline 2N3055

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #45 on: July 26, 2020, 06:15:18 pm »
Battery power should be OK, here is what I am having in mind.

In many old 20MHz CROs, there is electrostatic CRT and the cathode is driven at around -2KV DC, whereas a lot of the driving signals has differential voltage of 20 V DC or less.
Measuring that with an oscilloscope referenced to ground will produce a big bang or at best the GFCI will trigger.
A 2KV to ground (common mode range) differential probe is a rare and expensive device.

230€

Micsig DP20003 100MHz
Maximum Differential Test Voltage(DC+AC PK-PK)           560 V (200 X)/ 5600 V (2000 X)
Maximum input common mode voltage(DC+AC PK-PK)   560 V (200 X)/ 5600 V (2000 X)

 

Offline pplaninsky

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #46 on: July 26, 2020, 07:38:33 pm »
Thanks for the hint!
However, the specs state.

Maximum input common mode voltage: CAT II 1000V

Isn't that unsuatable for differential rails that are 2KV referenced to ground?
Otherwise, not that this is a cheap probe 230 EUR - but is somewhat acceptable comparead to thousands of EURO.
 

Offline 2N3055

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #47 on: July 26, 2020, 08:15:13 pm »
Thanks for the hint!
However, the specs state.

Maximum input common mode voltage: CAT II 1000V

Isn't that unsuatable for differential rails that are 2KV referenced to ground?
Otherwise, not that this is a cheap probe 230 EUR - but is somewhat acceptable comparead to thousands of EURO.

No not cheap, but affordable.  and decent qualitiy.
CAT II 1000V is referring to protection when working on higher energy circuits. For your use 5600 V P-P max apply..
 

Offline theoldwizard1

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #48 on: September 11, 2020, 03:07:19 pm »
I just re-watched Dave's review of this 'scope.  His conclusions are spot on.  If you call it a 200MS/sec/channel 'scope (assuming they are actually gathering data using an out of phase clock per channel) it is not a bad 'scope for the price.  If they could fix some of the software/UI issues this would be a really decent 'scope for the money !

Sadly, I don't expect any firmware upgrades, at least in the near future.

There are ADC that can do 1GS/sec in a similar price range as the ADC9288 but how how good is that front end ?  Of course they are probably using a clone that they can get for a few pennies.
 

Offline piyush

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Re: EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review
« Reply #49 on: September 26, 2020, 04:15:56 am »
Hello Friends,

I am interested in redoing UI with QT if firmware is usable.

Besides I order one but received with Chinese language, I talk to supplier then they said can't change language, I also ask to provide firmware to upgrade but they can't, Can any one please help me to provide dd image of English version sd card ?

Thanks


 


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