Author Topic: FNIRSI-1013D "100MHz" tablet oscilloscope  (Read 25971 times)

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Offline skoehler

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #125 on: June 30, 2020, 03:38:49 pm »
As far as I was aware, the claimed (fake) specs were always 100MHz bandwidth at 1GSa/s. That's why people like wolfy007 would even try frequencies like 85MHz. If it was 100MSa/s, you would probably expect things to go wrong above 20MHz.
 
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Offline GeorgeOfTheJungle

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #126 on: June 30, 2020, 04:00:41 pm »
100MHz, 100MSa/s:
[attachimg=1]

« Last Edit: June 30, 2020, 04:03:43 pm by GeorgeOfTheJungle »
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Offline CDaniel

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #127 on: June 30, 2020, 07:16:20 pm »
The Tektronix is a combo analog + digital scope , made in the period of transition from analog to digital .  Used in analog mode ( like an old scope ) has 100MHz bandwidth , but if you want the digital stuff like measurements on screen  , cursors , storage is just 100MS/sec so much lower usable bandwidth
« Last Edit: June 30, 2020, 07:28:17 pm by CDaniel »
 
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Offline skoehler

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #128 on: June 30, 2020, 07:41:59 pm »
What CDaniel said: the given bandwidth is the spec of the analog part, which is responsible for putting the lines on the screen. This has nothing to do with the problems that digitial scopes face, when they have to reconstruct a sine wave based on a digital discrete-time signal, i.e., a sequence of digital samples.
 

Offline GeorgeOfTheJungle

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #129 on: June 30, 2020, 08:08:32 pm »
But when I hear 100MHz/100MSa/s the 2232 automatically comes to my mind :-)

The analog bandwidth is a must, but the MSa/s for repetitive signals isn't... back then, that's what the "repetitive store mode" was for. Non repetitive and one shots are a different beast of course.

The 2232 has been my favourite scope for more than 20 years, I still like it, I still use it sometimes. Memory depth: 1k/4k samples :-) It's got the best user interface of any scope I've ever seen. Wanna save a waveform? Press store and the memory number. Want to recall a saved waveform? Simply press the memory number 1..4 and voilá. A pleasure to use, no infinite menus and submenus, each function has a dedicated button. CRT + awesome vector graphics. I love it.
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Offline CDaniel

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #130 on: June 30, 2020, 08:30:03 pm »
In a complete digital scope even if you have the input amplifier analog bandwidth you won't see it on screen  if the ADC sample rate is low ...
In my opinion this cheap chineese scopes are just toys usable for beginers , better buy an used portable old Fluke , like model 97 which have an extra powerfull meter
« Last Edit: June 30, 2020, 08:41:49 pm by CDaniel »
 

Offline UniSoft

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #131 on: July 01, 2020, 11:36:31 am »
1013D doesn't have 1GSa/s!!!
But the way, I made that screenshots of internal parts on the first page...
name of ADC IC is erased, but by pinout can see that this is AD9288-100MSa/s
(also frequency on ENC(A,B) pins is 100MHz).
so the real rate is 200MSa/s on each channel!!!
 

Offline skoehler

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #132 on: July 01, 2020, 11:53:11 am »
1013D doesn't have 1GSa/s!!!
Yes, we know that already.

But the way, I made that screenshots of internal parts on the first page...
name of ADC IC is erased, but by pinout can see that this is AD9288-100MSa/s
(also frequency on ENC(A,B) pins is 100MHz).
so the real rate is 200MSa/s on each channel!!!
I don't understand. You say 100MSa/s, then 100MHz, and then you conclude with 200Ma/s per channel! That doesn't workout. Do you mean 200MSa/s for both channels (meaning 100MSa/s per channel)?

As far as I understand ENCA/B defined the sample rate of the ADC. How can the scope reconstruct and show a sine wave of up to 85MHz with only 100MSa/s per channel? That's a mathematical impossibility.

If you measured ENCA/B, that rules our the possibility that they "overclock" the ADCs. Is there a variant of the AD9288 that samples on both edges of ENCA/B?
« Last Edit: July 01, 2020, 11:59:29 am by skoehler »
 

Offline rf-loop

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #133 on: July 01, 2020, 12:42:31 pm »
1013D doesn't have 1GSa/s!!!
Yes, we know that already.

But the way, I made that screenshots of internal parts on the first page...
name of ADC IC is erased, but by pinout can see that this is AD9288-100MSa/s
(also frequency on ENC(A,B) pins is 100MHz).
so the real rate is 200MSa/s on each channel!!!
I don't understand. You say 100MSa/s, then 100MHz, and then you conclude with 200Ma/s per channel! That doesn't workout. Do you mean 200MSa/s for both channels (meaning 100MSa/s per channel)?

As far as I understand ENCA/B defined the sample rate of the ADC. How can the scope reconstruct and show a sine wave of up to 85MHz with only 100MSa/s per channel? That's a mathematical impossibility.

If you measured ENCA/B, that rules our the possibility that they "overclock" the ADCs. Is there a variant of the AD9288 that samples on both edges of ENCA/B?

Have you ever seen AD9288 data sheet and understood it.  This is old ADC what have used in tens on different manufacturers low end scopes even models what have 1Gsa/s sampling speed and years these have handled and discussed here in forum repeatedly. Of course less today due to fact that most manufacturers use more modern circuits today. One famous model was Rigol1000E models, also Siglent, also hantek and many others. Most of them put 5 ADC inside scope for get 1Gsa/s (interleaved).
Now I have seen OP fist images and explanation. There can see 2 pcs ADC chips. One for each channel. So, IF they are AD9288 or clones,  it can give 200Msa/s both channels simultaneously.  Just because inside one ADC IC there is 2pcs 100Msa/s ADC. And these can connect for interleaving.  Some of these chips are manufaturer graded to slower clock, example for 40MHz just because all chips are not best ones. All tey can work with 100MHz clock but all do not meet all analog conversion specs with this speed so manufacturer have classified these chips for different speed class. In history it was just fun when Rigol use these 40M classified chips as 100M and remove all labels from chips.

« Last Edit: July 01, 2020, 12:44:26 pm by rf-loop »
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Offline skoehler

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #134 on: July 01, 2020, 12:55:08 pm »
interleaving
That makes sense. So it's two 100MSa/s ADCs interleaved for both channels giving us 200MSa/s.
So that explains why things go really bad above 85 MHz.

So following the 1:5 rule, the 1013d is a 40MHz scope.
 

Offline rf-loop

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #135 on: July 01, 2020, 02:00:45 pm »
interleaving
That makes sense. So it's two 100MSa/s ADCs interleaved for both channels giving us 200MSa/s.
So that explains why things go really bad above 85 MHz.

So following the 1:5 rule, the 1013d is a 40MHz scope.

Roughly saying yes if we talk about "single shot" usable BW. If there is available way or other implemented repetitive  acquisition mode it change this.
If practice and theory is not equal it tells that used application of theory is wrong or the theory itself is wrong.
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Offline martinot

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #136 on: July 02, 2020, 02:58:57 pm »
The reason I'm not buying the 1013d is that I am thinking about buying a Siglent 1202X-E. It's available though German shops and I will have a more mature product, higher bandwidth, etc.

Have you seen the Micsig tablets?

Same form factor and touchscreen as a 1013D, more powerful than a Siglent.

https://micsig.aliexpress.com/store/group/Tablet-Oscilloscope/1293611_509734614.html

OK, a bit more expensive than the Siglent but if that's what you're after then it's worth saving up a little bit more.

This Micsig looks to be a perfect scope for portability, but still better value than the classic "cheap" desktop scopes by the other Chinse brands (Rigol, Siglent, Owon, etc.).

Thinking about to get this one with button/knobs on the side:

https://www.batronix.com/shop/oscilloscopes/Micsig-STO1104C.html
https://www.batronix.com/files/Micsig/STO1000/STO1000C-data-sheet.pdf
 

Offline EEVblog

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #137 on: July 04, 2020, 06:47:51 am »
I have one.
Same lame interleaved sampling AD9288 100MS/s ADC, one per channel. So 200MS/s if using bi-phase clock.

FNIRSI 1013D Portable Tablet Oscilloscope PCB by Dave Jones, on Flickr
« Last Edit: July 04, 2020, 06:49:57 am by EEVblog »
 
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Online Fungus

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #138 on: July 04, 2020, 11:38:48 am »
I have one.

I'm still on the fence.

Same lame interleaved sampling AD9288 100MS/s ADC

That perfectly fits the observation that the signal goes to hell above 40MHz but it's a MASSIVE lie by the manufacturers.

A new low for testgear number exaggeration/inflation?

 

Offline EEVblog

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #139 on: July 04, 2020, 11:44:56 am »
Same lame interleaved sampling AD9288 100MS/s ADC
That perfectly fits the observation that the signal goes to hell above 40MHz but it's a MASSIVE lie by the manufacturers.
A new low for testgear number exaggeration/inflation?

Yep. It's 200MS/s actually as both ADC's in the one chip are clocked out of phase, same signal goes into both ADC channels.
I'd call it 20MHz and be done with it.
Still a dual channel 20MHz 7" touch screen portable tablet scope for $140 isn't bad.
 
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Online Fungus

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #140 on: July 04, 2020, 12:00:37 pm »
Yep. It's 200MS/s actually as both ADC's in the one chip are clocked out of phase, same signal goes into both ADC channels.

Is it one chip per channel (the two unmarked chips at bottom right)?

If so that's "400MSamples/sec" - nothing to be ashamed of but I don't see anybody advertising that number. They all have numbers that start with a "1".

Still a dual channel 20MHz 7" touch screen portable tablet scope for $140 isn't bad.

Yep.
« Last Edit: July 04, 2020, 12:04:27 pm by Fungus »
 
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Offline skoehler

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #141 on: July 04, 2020, 01:39:20 pm »
Yep. It's 200MS/s actually as both ADC's in the one chip are clocked out of phase, same signal goes into both ADC channels.
Is it one chip per channel (the two unmarked chips at bottom right)?

If so that's "400MSamples/sec" - nothing to be ashamed of but I don't see anybody advertising that number. They all have numbers that start with a "1".
It's still 200MSa/s as explained above. Multiplying by two just because you have two channels doesn't make any sense. Yes, some scopes have 1GSa/s when using one channel and only 500MSa/s when using two channels, but this scope has 200MSa/s regardless of how many channels you use. At least that's what I understood so far. And the "marketing" is off by a factor of 5, which is pretty big lie that's totally unnecessary.
 

Offline EEVblog

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #142 on: July 04, 2020, 01:58:20 pm »
Yep. It's 200MS/s actually as both ADC's in the one chip are clocked out of phase, same signal goes into both ADC channels.
Is it one chip per channel (the two unmarked chips at bottom right)?
If so that's "400MSamples/sec" - nothing to be ashamed of but I don't see anybody advertising that number. They all have numbers that start with a "1".

Yes, one dual ADC per channel. As far as I see, no way to combine 4 ADC's for one channel.
 

Online Fungus

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #143 on: July 04, 2020, 02:56:42 pm »
Yes, one dual ADC per channel. As far as I see, no way to combine 4 ADC's for one channel.

And not much point if the front end isn't up to the job.

(or maybe the front end is up to the job and it's the firmware that's going to hell, I assume this will be covered in the video  :)  )
« Last Edit: July 04, 2020, 02:59:29 pm by Fungus »
 

Offline UniSoft

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #144 on: July 04, 2020, 03:14:51 pm »
If to click save without SD card then firmware complete hangs...
Without a battery, the MCU should go into boot mode (this is implemented in the circuit), but it does not seem to work.
There is no way to update the firmware.
 

Offline skoehler

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #145 on: July 04, 2020, 03:28:33 pm »
Without a battery, the MCU should go into boot mode (this is implemented in the circuit), but it does not seem to work.

What do you mean by "without a battery" ? Does it mean, that you disconnect the battery and power this device via USB only?

There is no way to update the firmware.
If true, that would be sad.
 

Offline UniSoft

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #146 on: July 04, 2020, 05:17:37 pm »
What do you mean by "without a battery" ? Does it mean, that you disconnect the battery and power this device via USB only?
Yes, it is...
 

Offline AlcidePiR2

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #147 on: July 06, 2020, 04:09:08 pm »
Still a dual channel 20MHz 7" touch screen portable tablet scope for $140 isn't bad.

I agree. The main limitation I think  is not the 20 Mhz bandwidth, but the 50 mV  sensitivity.

Besides,   one can understand that they can find many ways to measure the bandwidth, but  I find that their most outrageous claim is the  < 3ns  rise time
while I measured 12 ns  at least, using Leo Bodnar  tool.
 

Offline iscle

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #148 on: July 06, 2020, 05:52:56 pm »
Without a battery, the MCU should go into boot mode (this is implemented in the circuit), but it does not seem to work.
There is no way to update the firmware.

Well, actually the firmware is stored ouside of the SOC in the SPI flash, so it can be updated, just not without opening the device up...
 

Offline CDaniel

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Re: FNIRSI-1013D "100MHz" tablet oscilloscope
« Reply #149 on: July 07, 2020, 06:40:38 am »
Seriously , updates for a thing that was made like a toy with big hardware limitations ...
 


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