EEVblog #1228 - Do Digital Scopes Have REAL Verniers?

[EEVblog]

Do digital oscilloscopes have REAL vertical vernier controls?
Let's probe a scope up the clacker to find out!

[BravoV]

Imo, this video shows a huge advantages having a 4 inputs scope, compared to 2 when probing digital lines like the example at the Siglent scope's front end VGA. 

[rf-loop]

Dave,

when you do this kind of investigation and then claim some things like example difference between 500uV and 1mV/div. (position around 12:00/18:55 in video) Now you claim it is not true 500uV/div just because you do not see control data change in ONE place.   Are you seriously making this claim based only to this ONE single fact without anything else. Is it now better to take spoon in to hand and start first thinking and and after thinking and study is ready, then talk and publish claims and conclusions based to all facts.

 Look what happen AND where happen when you change example from 500uV/div to 510uV/div and so on, every fine step to 1mV/div. Also investigate real ADC data. If 500uV is just digital magnification like example 1mV/div in Keysight derived from (I do not remember if from 2mV/div or something like it) lover sensitivity you can also see it in data, you can see it even on the screen if you know how to look it with some signal+noise. If I remember right some model do 1mV/div as digital "image" magnification from 4mV/div. Whole full scale is now 6 bit data (64 steps).  Have you seen this kind of digital magnification in Siglent (this model). Yes there is this method in older SDS2000(X) But how about SDS1000X-E. ( it is very different).  If we use word digital magnification... well, I think it need go bit more deep to think what are these.

Why do you make such simple and hasty conclusions and arguments? Before submitting the conclusions, the matter should really be examined more closely. If your claim is right or wrong it is not now case.  But now your claim is not based to nearly anything. (exept that VGA control byte do not change between 500uV and 1mV/div. Are you seriusly as real engineer need be with this claim. Now you have no ground under your feet here. First you need investigate, collect data and many kind of evidences. After then come out again and tell with data that there is no real full ADC scale 500uV/div (or 530uV/div or what ever).
If go just roughly: 13*50 fine steps = 650 steps. (but yes, part of thing is also 3 different relay selected V bands. Example in Voltage band I,  500uV/div - 118mV/div,  there is 358 steps if I count right.  Band II and III naturally have less steps due to more narrow Voltage ranges)

5 points tip:

VGA gain control range max is 8 bit.  Think!!!   Think again!
example from 500uV/div to 1mV/div there is 50 step. From 1mV/div to 2mV/div again 50 steps.
from 2mV/div to 5mV/div again 50 steps and so on.... ( I have also told it already in this other thread)
Now think again. Whole range from 500uV/div up to 10V/div and how many steps there is total (do not care if 1-2-5 major steps or fine steps. Just count total. Think again this 8bit cotrol byte.  No any bell ringing your head? 

Then think one other data sheet where are these:

The device includes a digital programmable gain in addition to the Full-scale control.
There will be no missing codes for gain settings lower than 32x (30dB), due to higher than 8 bit resolution internally.

And, using this together with... and so on.
Media business and Engineer work are some times different or is it better say, it need be differerent.

[EEVblog]

Dave,

when you do this kind of investigation and then claim some things like example difference between 500uV and 1mV/div. (position around 12:00/18:55 in video) Now you claim it is not true 500uV/div just because you do not see control data change in ONE place.   Are you seriously making this claim based only to this ONE single fact without anything else. Is it now better to take spoon in to hand and start first thinking and and after thinking and study is ready, then talk and publish claims and conclusions based to all facts.

 Look what happen AND where happen when you change example from 500uV/div to 510uV/div and so on, every fine step to 1mV/div. Also investigate real ADC data. If 500uV is just digital magnification like example 1mV/div in Keysight derived from (I do not remember if from 2mV/div or something like it) lover sensitivity you can also see it in data, you can see it even on the screen if you know how to look it with some signal+noise. If I remember right some model do 1mV/div as digital "image" magnification from 4mV/div. Whole full scale is now 6 bit data (64 steps).  Have you seen this kind of digital magnification in Siglent (this model). Yes there is this method in older SDS2000(X) But how about SDS1000X-E. ( it is very different).  If we use word digital magnification... well, I think it need go bit more deep to think what are these.

Why do you make such simple and hasty conclusions and arguments? Before submitting the conclusions, the matter should really be examined more closely. If your claim is right or wrong it is not now case.  But now your claim is not based to nearly anything. (exept that VGA control byte do not change between 500uV and 1mV/div. Are you seriusly as real engineer need be with this claim. Now you have no ground under your feet here. First you need investigate, collect data and many kind of evidences. After then come out again and tell with data that there is no real full ADC scale 500uV/div (or 530uV/div or what ever).
If go just roughly: 13*50 fine steps = 650 steps. (but yes, part of thing is also 3 different relay selected V bands)

5 points tip:

VGA gain control range max is 8 bit.  Think!!!   Think again!
example from 500uV/div to 1mV/div there is 50 step. From 1mV/div to 2mV/div again 50 steps.
from 2mV/div to 5mV/div again 50 steps and so on.... ( I have also told it already in this other thread)
Now think again. Whole range from 500uV/div up to 10V/div and how many steps there is total (do not care if 1-2-5 major steps or fine steps. Just count total. Think again this 8bit cotrol byte.  No any bell ringing your head? 

Then think one other data sheet where are these:

The device includes a digital programmable gain in addition to the Full-scale control.
There will be no missing codes for gain settings lower than 32x (30dB), due to higher than 8 bit resolution internally.

And, using this together with... and so on.
Media business and Engineer work are some times different or is it better say, it need be differerent.

The ADC is 8 bit.
The chip gain does not change from 500uV to 1mV.
How on earth do you expect it not to have have digital gain at 500uV? 
A true 500uV/DIV front end amplifier would amplify the signal to the full scale ADC input. When the gain instruction to the chip clearly shows there is no change in amplifier gain, it's by definition not a true 500uV analog range.
But you are correct that the Siglent does not just "pixel double", it's doing some form of digital gain.

[rf-loop]

Dave,

when you do this kind of investigation and then claim some things like example difference between 500uV and 1mV/div. (position around 12:00/18:55 in video) Now you claim it is not true 500uV/div just because you do not see control data change in ONE place.   Are you seriously making this claim based only to this ONE single fact without anything else. Is it now better to take spoon in to hand and start first thinking and and after thinking and study is ready, then talk and publish claims and conclusions based to all facts.

 Look what happen AND where happen when you change example from 500uV/div to 510uV/div and so on, every fine step to 1mV/div. Also investigate real ADC data. If 500uV is just digital magnification like example 1mV/div in Keysight derived from (I do not remember if from 2mV/div or something like it) lover sensitivity you can also see it in data, you can see it even on the screen if you know how to look it with some signal+noise. If I remember right some model do 1mV/div as digital "image" magnification from 4mV/div. Whole full scale is now 6 bit data (64 steps).  Have you seen this kind of digital magnification in Siglent (this model). Yes there is this method in older SDS2000(X) But how about SDS1000X-E. ( it is very different).  If we use word digital magnification... well, I think it need go bit more deep to think what are these.

Why do you make such simple and hasty conclusions and arguments? Before submitting the conclusions, the matter should really be examined more closely. If your claim is right or wrong it is not now case.  But now your claim is not based to nearly anything. (exept that VGA control byte do not change between 500uV and 1mV/div. Are you seriusly as real engineer need be with this claim. Now you have no ground under your feet here. First you need investigate, collect data and many kind of evidences. After then come out again and tell with data that there is no real full ADC scale 500uV/div (or 530uV/div or what ever).
If go just roughly: 13*50 fine steps = 650 steps. (but yes, part of thing is also 3 different relay selected V bands)

5 points tip:

VGA gain control range max is 8 bit.  Think!!!   Think again!
example from 500uV/div to 1mV/div there is 50 step. From 1mV/div to 2mV/div again 50 steps.
from 2mV/div to 5mV/div again 50 steps and so on.... ( I have also told it already in this other thread)
Now think again. Whole range from 500uV/div up to 10V/div and how many steps there is total (do not care if 1-2-5 major steps or fine steps. Just count total. Think again this 8bit cotrol byte.  No any bell ringing your head? 

Then think one other data sheet where are these:

The device includes a digital programmable gain in addition to the Full-scale control.
There will be no missing codes for gain settings lower than 32x (30dB), due to higher than 8 bit resolution internally.

And, using this together with... and so on.
Media business and Engineer work are some times different or is it better say, it need be differerent.

The ADC is 8 bit.
The chip gain does not change from 500uV to 1mV.
How on earth do you expect it not to have have digital gain at 500uV? 

ADC chip OUTPUT is 8bit. Yes. It is other thing.

PLease, kindly, do your home works and some real investigation before start bullshit generator. 

Make tests and look raw ADC data. Do you find 128 steps or 256 steps (7 or 8 bit data) when you look example 500uV/div raw data.

In Siglent SDS1000X-E It is NOT at all like example Keysight digital "image" magnification from ADC output data when they magnify from 4mV/div first to 2mV/div and even then to 1mV/div what have only 64 level steps (6bit).

[tautech]

Dave,

when you do this kind of investigation and then claim some things like example difference between 500uV and 1mV/div. (position around 12:00/18:55 in video) Now you claim it is not true 500uV/div just because you do not see control data change in ONE place.   Are you seriously making this claim based only to this ONE single fact without anything else. Is it now better to take spoon in to hand and start first thinking and and after thinking and study is ready, then talk and publish claims and conclusions based to all facts.

 Look what happen AND where happen when you change example from 500uV/div to 510uV/div and so on, every fine step to 1mV/div. Also investigate real ADC data. If 500uV is just digital magnification like example 1mV/div in Keysight derived from (I do not remember if from 2mV/div or something like it) lover sensitivity you can also see it in data, you can see it even on the screen if you know how to look it with some signal+noise. If I remember right some model do 1mV/div as digital "image" magnification from 4mV/div. Whole full scale is now 6 bit data (64 steps).  Have you seen this kind of digital magnification in Siglent (this model). Yes there is this method in older SDS2000(X) But how about SDS1000X-E. ( it is very different).  If we use word digital magnification... well, I think it need go bit more deep to think what are these.

Why do you make such simple and hasty conclusions and arguments? Before submitting the conclusions, the matter should really be examined more closely. If your claim is right or wrong it is not now case.  But now your claim is not based to nearly anything. (exept that VGA control byte do not change between 500uV and 1mV/div. Are you seriusly as real engineer need be with this claim. Now you have no ground under your feet here. First you need investigate, collect data and many kind of evidences. After then come out again and tell with data that there is no real full ADC scale 500uV/div (or 530uV/div or what ever).
If go just roughly: 13*50 fine steps = 650 steps. (but yes, part of thing is also 3 different relay selected V bands)

5 points tip:

VGA gain control range max is 8 bit.  Think!!!   Think again!
example from 500uV/div to 1mV/div there is 50 step. From 1mV/div to 2mV/div again 50 steps.
from 2mV/div to 5mV/div again 50 steps and so on.... ( I have also told it already in this other thread)
Now think again. Whole range from 500uV/div up to 10V/div and how many steps there is total (do not care if 1-2-5 major steps or fine steps. Just count total. Think again this 8bit cotrol byte.  No any bell ringing your head? 

Then think one other data sheet where are these:

The device includes a digital programmable gain in addition to the Full-scale control.
There will be no missing codes for gain settings lower than 32x (30dB), due to higher than 8 bit resolution internally.

And, using this together with... and so on.
Media business and Engineer work are some times different or is it better say, it need be differerent.

The ADC is 8 bit.
The chip gain does not change from 500uV to 1mV.
How on earth do you expect it not to have have digital gain at 500uV? 

FFS Dave think !
Can you vernier lower than 500uV/div ?
NO
Only below 1mV/div !

[EEVblog]

WTF is your problem guys.
The ANALOG GAIN IS THE SAME for both 1mV and 500uV ranges, do you deny this?
Unless there another x2 amp somewhere else in the analog chain that's being switched in then the 500uV must be doing digital gain somewhere else in the system, surely?
In fact the analog gain is the same for the 2mV, 1mV and 500uV ranges.

[EEVblog]

In Siglent SDS1000X-E It is NOT at all like example Keysight digital "image" magnification from ADC output data when they magnify from 4mV/div first to 2mV/div and even then to 1mV/div what have only 64 level steps (6bit).

I'm not saying it is.
I'm just saying the the FRONT END ANALOG GAIN is the SAME for the 2mV, 1mV, and 500uV ranges.

[rf-loop]

WTF is your problem guys.
The ANALOG GAIN IS THE SAME for both 1mV and 500uV ranges, do you deny this?
Unless there another x2 amp somewhere else in the analog chain that's being switched in then the 500uV must be doing digital gain somewhere else in the system, surely?

Yes, but also then no. Please do you home works.
VGA is before ADC yes and it is only place where is doing analog gain adjustment.
But after then you forget some important thing. ADC have 8 bit output. Yes it is.
But with Analog HMCAD1511 we can do things different. We do not need magnify (reduce resolution) after its output.
Think now carefully. How example Keysight do magnification from 2mV/div to 1mV/div. It magnify this ADC output.  Siglent do not.  After magnification, ADC output is still 8 bit and it use still this full resolution.  You need only take out 500uV/div raw data out and look. I ask, is it 7bit or 8 bit data. Please, read HMCAD1511 data sheet and pleease read it as long so that you also understand what you read there.
In previous I have emphasised this important thing... due to higher than 8 bit resolution internally.

[EEVblog]

It uses the HAD1511 ADC
https://www.analog.com/media/en/technical-documentation/data-sheets/hmcad1511.pdf
It has internal digital gain after the ADC, it must be using that.

If you have evidence that the gain changes IN THE ANALOG FRONT END then present your evidence.

[EEVblog]

WTF is your problem guys.
The ANALOG GAIN IS THE SAME for both 1mV and 500uV ranges, do you deny this?
Unless there another x2 amp somewhere else in the analog chain that's being switched in then the 500uV must be doing digital gain somewhere else in the system, surely?

Yes, but also then no. Please do you home works.
VGA is before ADC yes and it is only place where is doing analog gain adjustment.
But after then you forget some important thing. ADC have 8 bit output. Yes it is.
But with Analog HMCAD1511 we can do things different. We do not need magnify (reduce resolution) after its output.
Think now carefully. How example Keysight do magnification from 2mV/div to 1mV/div. It magnify this ADC output.  Siglent do not.  After magnification, ADC output is still 8 bit and it use still this full resolution.  You need only take out 500uV/div raw data out and look. I ask, is it 7bit or 8 bit data. Please.

I am not going to go and analyse the ADC output data to satisfy your little bug-bear. You go do it if it's so important to you.
My investigation and comments stop at the analog front end.

[rf-loop]

WTF is your problem guys.
The ANALOG GAIN IS THE SAME for both 1mV and 500uV ranges, do you deny this?
Unless there another x2 amp somewhere else in the analog chain that's being switched in then the 500uV must be doing digital gain somewhere else in the system, surely?

Yes, but also then no. Please do you home works.
VGA is before ADC yes and it is only place where is doing analog gain adjustment.
But after then you forget some important thing. ADC have 8 bit output. Yes it is.
But with Analog HMCAD1511 we can do things different. We do not need magnify (reduce resolution) after its output.
Think now carefully. How example Keysight do magnification from 2mV/div to 1mV/div. It magnify this ADC output.  Siglent do not.  After magnification, ADC output is still 8 bit and it use still this full resolution.  You need only take out 500uV/div raw data out and look. I ask, is it 7bit or 8 bit data. Please.

I am not going to go and analyse the ADC output data to satisfy your little bug-bear. You go do it if it's so important to you.
My investigation and comments stop at the analog front end.

500uV/div is still full 8 bit ADC resolution because magnification is done there using it internal higher resolution. Period.

[EEVblog]

If you really have a problem with this then I can include a screen shot of the HAD1511 datasheet and a comment that the digital gain is being done in there. Will that shut you up?

[EEVblog]

WTF is your problem guys.
The ANALOG GAIN IS THE SAME for both 1mV and 500uV ranges, do you deny this?
Unless there another x2 amp somewhere else in the analog chain that's being switched in then the 500uV must be doing digital gain somewhere else in the system, surely?

Yes, but also then no. Please do you home works.
VGA is before ADC yes and it is only place where is doing analog gain adjustment.
But after then you forget some important thing. ADC have 8 bit output. Yes it is.
But with Analog HMCAD1511 we can do things different. We do not need magnify (reduce resolution) after its output.
Think now carefully. How example Keysight do magnification from 2mV/div to 1mV/div. It magnify this ADC output.  Siglent do not.  After magnification, ADC output is still 8 bit and it use still this full resolution.  You need only take out 500uV/div raw data out and look. I ask, is it 7bit or 8 bit data. Please.

I am not going to go and analyse the ADC output data to satisfy your little bug-bear. You go do it if it's so important to you.
My investigation and comments stop at the analog front end.

500uV/div is still full 8 bit ADC resolution. Period.

The ADC has a voltage reference. That voltage reference and the analog gain will be scaled for 1mV( or maybe 2mV?)/dev, so let's say 16mV total signal input.
On the 500uV range the analog gain is the SAME a the other ranges, so there is now only a 4mV FS signal on the ADC input that has a 16mV reference.
Look at the datasheet, the gain is done "digitally" after the ADC.
I don't care about the performance, the fact is the gain is done digitally after the ADC output wiht the same voltage reference as the higher ranges.

[JxR]

I have no desire to get in the middle of this current discussion, but I watched and enjoyed the video after I got the email notification.  Just wanted to point out that you still have the video as unlisted on YouTube, in case you meant to update that.

[EEVblog]

I have no desire to get in the middle of this current discussion, but I watched and enjoyed the video after I got the email notification.  Just wanted to point out that you still have the video as unlisted on YouTube, in case you meant to update that.

Full release is tomorrow.

[rf-loop]

If you really have a problem with this then I can include a screen shot of the HAD1511 datasheet and a comment that the digital gain is being done in there. Will that shut you up?

Yes, exactly. It is there. And now we need bit think when we talk digital magnification. When we talk just "digital magnification"  because inside group "digital magnification" can be very different things. . And just because this ADC have more internal resolution than just 8bit what is its final output resolution (some reason I believe Analog Devices claims about 1511 ADC). 

It is very different if we just magnify 8bit ADC raw output data  (like example some Keysight models do) or magnify internally using ADC extra internal resolution and then still get out and use full 8bit output. Result is different. (oh yes, noise figure etc not so nice if compare to system where is very good low noise analog front end with amplifier before ADC and then get 5mV full scale 0-255.  but still this system what Siglent use can claim it is full 8bit resolution 500uV/div.

[EEVblog]

New version rendering now to shut everyone up. Well, shut up the rabid Siglent fanboys 

[tautech]

Look at the datasheet, the gain is done "digitally" after the ADC.
I don't care about the performance, the fact is the gain is done digitally after the ADC output wiht the same voltage reference as the higher ranges.

Yet you said "software" magnified in the video @ ~12.10

[EEVblog]

Look at the datasheet, the gain is done "digitally" after the ADC.
I don't care about the performance, the fact is the gain is done digitally after the ADC output wiht the same voltage reference as the higher ranges.

Yet you said "software" magnified in the video @ ~12.10

Oh FFS, are you going to nit pick every word in my videos?
I'm not going to go back and dub over that.
I have included an overlay correction, and if you don't like it, tough titties.

[rf-loop]

Journalists and Engineers...

[EEVblog]

Journalists and Engineers...

What are you insinuating?
If you aren't careful I'll leave the video as-is and not correct it, just to piss someone off...

[Barny]

A educational video on the main channel below 45 minutes?
Who are you and what have you done to Dave Jones our Mr. EEVblog the waffle master?
(Mhmmmm waffles)
Are you a repiloid from the big anti free energy organisation?


Funn asside:
Thanks for the educational video.
Now I know another thing I miss on my old, big Rigol scope. 

[EEVblog]

A educational video on the main channel below 45 minutes?
Who are you and what have you done to Dave Jones our Mr. EEVblog the waffle master?
(Mhmmmm waffles)

I was disappointed by the 19min length, I thought it'd be about 12-13min.

[EEVblog]

Video uploaded, processing now.