MSO5000 Bode Plot Capability: Is it Good Enough? [Many tips about a 1st scope]

[Fungus]

With the 2ch AWG and XY mode in the SDS1104X-E we can also have a play at curve tracing too:
https://www.eevblog.com/forum/testgear/fooln-around-with-dso-awg/

You can do curve tracing like this with any 2 channel function generator and oscilloscope.

Yep, and OP already owns a Uni-T signal generator.

[egonotto]

Hello,

@2N3055: For a stability analysis it seems to me that you need an injection transformer. Unfortunately, I don't have that.
The problem with such measurements seems to me to be the small voltage. This could be remedied with a suitable preamplifier.

Best regards
egonotto

[balnazzar]

Thanks, I searched for the string "SAG1021I" inside the datasheet, that's why I didn't find the damn specs...

[balnazzar]

Ok, ordered both the 1104x-e and the AD2 (with bnc adapter).

I'll evaluate if I also need another goddamn signal generator (that right now I couldn't buy in any case...).

[2N3055]

So, if I stimulate the circuit with an external WG, the AD2 will bodeplot its response? Thanks.

No, Bode plot and impedance analysis works by controlling generator and scope in synchronization.  AD2 has internal AWG and uses that one...No support for external AWG.

Weird. My copy of the manual says the generator can be external. You might know that if you owned an AD2...

PS: Can your oscilloscope do this?

Thank you for contributing quality content!!
Is this external generator recent addition? I did look into documentation when I was contemplation buying one and don't remember that.. It was long ago though..

One drawback of Bode plot with external generator implemented this way is that you cannot control it in this tracking mode. That means that variable level stimulus is not available which is not strictly necessary in theory, but is very important with difficult loads and with very low signals to get good measurements.
Also it doesn't know exact frequency but has to measure it, but that is not important because frequency to mHz is not very important here.

[2N3055]

Hello,

@2N3055: For a stability analysis it seems to me that you need an injection transformer. Unfortunately, I don't have that.
The problem with such measurements seems to me to be the small voltage. This could be remedied with a suitable preamplifier.

Best regards
egonotto

It has been show that you can use a common mode choke in a pinch.. I tried with Coilcraft CMT4-10-15L and it gave good enough results for noncritical work. Also I took one of these and removed windings and made windings from CAT6 cable (there was a topic here on making one at home) and that one worked well too.

You could use preamp. You can use external amplifier for gen too. As I said to Fungus, dynamic range is being extended by fact that some scopes have good sensitivity built in, and also if you have generator synchronized, you vary stimulus level.
But if you add preamp you need to scale manually.

Beauty of Siglent Bode Plot II is that all of those shenanigans are being taken care of automatically. It simply works.
Only other Bode plot software that I tried that was close to be so well integrated and streamlined in use is one in my Keysight 3000T. But only with built in generator, it cannot control external generator so it is limited in drive..

Siglent Bode Plot II support multiple channels, few more measurements etc. It really works well. It simply works..

[jasonRF]

Has the OP considered used equipment?  I don't know what the market and associated costs are when shopping from Europe, but in the US items like the Analog Discovery can be found with significant discounts.  An Analog Discovery 1 just sold on ebay a couple of days ago for $130.  Sure, it would cost an additional $40 for the BNC adapter and a couple of cheap probes, but it could still save $200 or more.   

I don't think I would go that route for my first 4-channel benchtop scope, but for an AD I think the risk is relatively low. 

Just a thought. 

jason

EDIT: I haven't used any of hte scopes mentioned in this thread, but I am surprised by the high price of the Instek GDS1054B in the EU.  In the US it often sells for less than the Rigol DS1054Z and the Siglent SDS1104X-U, which are closer competitors performance-wise.   On paper the Siglent SDS1104X-E seems like a much better scope than the instek: dual ADCs, potential upgrades for MSO and Bode capability, more sensitive front-end (500 uV/div, versus 1 mV/div that includes some digital zoom according to the GDS1054B thread on the forums), actual BNC for the trigger out (I am pretty sure the Instek uses the probe compensation as the trigger out...), etc.   Plus, if the OP already has the UniT siggen, there  is a possibility that they (or someone else on the forums) will eventually figure out how to make it work with the Siglent Bode plotting. 

Having said that, I thought seriously about purchasing a GDS1054B or GDS1202B for myself a number of months ago, but again I am in the US so price was a huge factor ($350 for 1054B vs $499 for SDS1104X-E; $310 for GDS1202B vs $380 for sds1202x-e).  Of course that is why I am familiar with some of the quirks of the Insteks that have been posted on the forums.

jason

[Fungus]

EDIT: I haven't used any of hte scopes mentioned in this thread, but I am surprised by the high price of the Instek GDS1054B in the EU.

Yep, it's a ridiculous difference.

The Insteks used to cost a lot more in the USA, too. They also had no serial decoders and weren't very hackable so they never gained much mindshare even though they're very fast and nice to use.

Now they've added the missing features and dropped the price a lot (less than a Rigol DS1054Z!). They deserve more recognition, but... 

[balnazzar]

Has the OP considered used equipment?  I don't know what the market and associated costs are when shopping from Europe, but in the US items like the Analog Discovery can be found with significant discounts.  An Analog Discovery 1 just sold on ebay a couple of days ago for $130.  Sure, it would cost an additional $40 for the BNC adapter and a couple of cheap probes, but it could still save $200 or more.   

I don't think I would go that route for my first 4-channel benchtop scope, but for an AD I think the risk is relatively low. 

Just a thought. 

jason

EDIT: I haven't used any of hte scopes mentioned in this thread, but I am surprised by the high price of the Instek GDS1054B in the EU.  In the US it often sells for less than the Rigol DS1054Z and the Siglent SDS1104X-U, which are closer competitors performance-wise.   On paper the Siglent SDS1104X-E seems like a much better scope than the instek: dual ADCs, potential upgrades for MSO and Bode capability, more sensitive front-end (500 uV/div, versus 1 mV/div that includes some digital zoom according to the GDS1054B thread on the forums), actual BNC for the trigger out (I am pretty sure the Instek uses the probe compensation as the trigger out...), etc.   Plus, if the OP already has the UniT siggen, there  is a possibility that they (or someone else on the forums) will eventually figure out how to make it work with the Siglent Bode plotting. 

Having said that, I thought seriously about purchasing a GDS1054B or GDS1202B for myself a number of months ago, but again I am in the US so price was a huge factor ($350 for 1054B vs $499 for SDS1104X-E; $310 for GDS1202B vs $380 for sds1202x-e).  Of course that is why I am familiar with some of the quirks of the Insteks that have been posted on the forums.

jason

Used equipment: considered. But if you read here and there, for example a known problem of the AD/AD2 is the fragilty of the micro-USB connector. If you aren't careful, it will get broken or partially broken very soon. A lot of people on forums lamented that having purchased an used one, they found the connector 'working' but basically broken and sloppily repaired.. And too few vendors on ebay offer the return option, not to mention the hassle.
As for the scopes, unless you want to wait months, it's very difficult to get a good, modern scope, held in good conditions for cheap prices on ebay. I bought both the Siglent and the AD2 on Amazon. If I won't like one or them (or both), super easy return with no shipping costs.

Prices in EU: There are two factors that impact badly. We have higher import duties for the distributors, and we have VAT for the end customer. That's why healthcare and education is free, here. It's not free, you just pay in advance.

[balnazzar]

Tell me one further thing, and indulge my ignorance. How much importance is to be given to the wavegen sampling rate?
I find it odd that cheap scopes can acquire signals up to 1 GSa/s while the generators get up to 150 on average.

Which are the usage cases where insufficient sampling rate by the gen is going to be a limiting factor?

I was reading the datasheets (yes  ) of the sdg1000x series: 150 MSa/s (note that my cheapo UNI-T gets to 200), whereas its slightly more expensive sibling, the sdg2000 gets to 1.2 GSa/s..

It's a huge differece, for just 150 eur more...

[nctnico]

That 1.2Gs/s is not for real. The actual samplerate for the SDG2k units is 300Ms/s

[jasonRF]

Has the OP considered used equipment?  I don't know what the market and associated costs are when shopping from Europe, but in the US items like the Analog Discovery can be found with significant discounts.  An Analog Discovery 1 just sold on ebay a couple of days ago for $130.  Sure, it would cost an additional $40 for the BNC adapter and a couple of cheap probes, but it could still save $200 or more.   

I don't think I would go that route for my first 4-channel benchtop scope, but for an AD I think the risk is relatively low. 

Just a thought. 

jason

EDIT: I haven't used any of hte scopes mentioned in this thread, but I am surprised by the high price of the Instek GDS1054B in the EU.  In the US it often sells for less than the Rigol DS1054Z and the Siglent SDS1104X-U, which are closer competitors performance-wise.   On paper the Siglent SDS1104X-E seems like a much better scope than the instek: dual ADCs, potential upgrades for MSO and Bode capability, more sensitive front-end (500 uV/div, versus 1 mV/div that includes some digital zoom according to the GDS1054B thread on the forums), actual BNC for the trigger out (I am pretty sure the Instek uses the probe compensation as the trigger out...), etc.   Plus, if the OP already has the UniT siggen, there  is a possibility that they (or someone else on the forums) will eventually figure out how to make it work with the Siglent Bode plotting. 

Having said that, I thought seriously about purchasing a GDS1054B or GDS1202B for myself a number of months ago, but again I am in the US so price was a huge factor ($350 for 1054B vs $499 for SDS1104X-E; $310 for GDS1202B vs $380 for sds1202x-e).  Of course that is why I am familiar with some of the quirks of the Insteks that have been posted on the forums.

jason

Used equipment: considered. But if you read here and there, for example a known problem of the AD/AD2 is the fragilty of the micro-USB connector. If you aren't careful, it will get broken or partially broken very soon. A lot of people on forums lamented that having purchased an used one, they found the connector 'working' but basically broken and sloppily repaired.. And too few vendors on ebay offer the return option, not to mention the hassle.
As for the scopes, unless you want to wait months, it's very difficult to get a good, modern scope, held in good conditions for cheap prices on ebay. I bought both the Siglent and the AD2 on Amazon. If I won't like one or them (or both), super easy return with no shipping costs.

Prices in EU: There are two factors that impact badly. We have higher import duties for the distributors, and we have VAT for the end customer. That's why healthcare and education is free, here. It's not free, you just pay in advance.

I obviously did not know about the AD fragility - glad you mentioned it.   I doubt I will ever recommend a used AD again!   I have so far had good luck with used test gear  (my basic dds function generator, super-basic power supply and fancy picoscope were all used ebay specials).     I of course completely agree about purchases from Amazon, as much as I hate to shove more money at the owner.   I buy from other vendors whenever possible for books and other supplies even if it costs a few extra dollars, but with their return policy it sometimes just makes the most sense to buy large-ticket items from  them.

Cheers,

Jason

[Fungus]

Used equipment: considered. But if you read here and there, for example a known problem of the AD/AD2 is the fragilty of the micro-USB connector. If you aren't careful, it will get broken or partially broken very soon.

Yep. It looks/feels quite fragile. I've always been very careful with mine.

Maybe some preemptive epoxy might be called for.

[tautech]

Has the OP considered used equipment?  I don't know what the market and associated costs are when shopping from Europe, but in the US items like the Analog Discovery can be found with significant discounts.  An Analog Discovery 1 just sold on ebay a couple of days ago for $130.  Sure, it would cost an additional $40 for the BNC adapter and a couple of cheap probes, but it could still save $200 or more.   

I don't think I would go that route for my first 4-channel benchtop scope, but for an AD I think the risk is relatively low. 

Just a thought. 

jason

EDIT: I haven't used any of hte scopes mentioned in this thread, but I am surprised by the high price of the Instek GDS1054B in the EU.  In the US it often sells for less than the Rigol DS1054Z and the Siglent SDS1104X-U, which are closer competitors performance-wise.   On paper the Siglent SDS1104X-E seems like a much better scope than the instek: dual ADCs, potential upgrades for MSO and Bode capability, more sensitive front-end (500 uV/div, versus 1 mV/div that includes some digital zoom according to the GDS1054B thread on the forums), actual BNC for the trigger out (I am pretty sure the Instek uses the probe compensation as the trigger out...), etc.   Plus, if the OP already has the UniT siggen, there  is a possibility that they (or someone else on the forums) will eventually figure out how to make it work with the Siglent Bode plotting. 

Having said that, I thought seriously about purchasing a GDS1054B or GDS1202B for myself a number of months ago, but again I am in the US so price was a huge factor ($350 for 1054B vs $499 for SDS1104X-E; $310 for GDS1202B vs $380 for sds1202x-e).  Of course that is why I am familiar with some of the quirks of the Insteks that have been posted on the forums.

jason

Highlighted a few of your points which I'll make comment on.
for my first 4-channel benchtop scope
Every buyer has a different need and budget and the wiser add addition functionality into their purchase for them to grow into.

Siglent SDS1104X-U
A very different beast to SDS1104X-E although they look very similar. X-U is more of a basic DSO without all the good bits the 4ch X-E has. In the context of this thread it falls well short on the feature set required.

potential upgrades for MSO and Bode capability
Bode plot capability is a standard feature in several Siglent DSO's and not an upgrade at all.

$380 for sds1202x-e
Again another model that doesn't measure up in the context of this thread as it also falls short on the feature set required however another series that can measure up is the 2GSa/s 2ch SDS2202X-E as these do have the webserver and Bode plot capability the OP requires but they are $ 620. But still the SDS1104X-E has a larger and better feature set.

[balnazzar]

That 1.2Gs/s is not for real. The actual samplerate for the SDG2k units is 300Ms/s

Two questions:
1. Why do they declare 1.2 GSa/s?
2. Is the actual sample rate of the 1000X even lower?

Thanks!

[balnazzar]

Siglent SDS1104X-U

$380 for sds1202x-e

Although I may seem super-lazy, I actually look at the datasheets (understanding them up to my modest competence, of course). I didn't even mention both of those scopes in my questions.. The first because for a modest 100 eur difference (street price) it lacks a lot of perks. Seems made just to offer a direct competitor for the 1054Z, dollar for dollar, feature for feature. The second because several times I already had need for at least 3 channels at the university lab.

[tautech]

Siglent SDS1104X-U

$380 for sds1202x-e

Although I may seem super-lazy, I actually look at the datasheets (understanding them up to my modest competence, of course). I didn't even mention both of those scopes in my questions.. The first because for a modest 100 eur difference (street price) it lacks a lot of perks. Seems made just to offer a direct competitor for the 1054Z, dollar for dollar, feature for feature. The second because several times I already had need for at least 3 channels at the university lab.

But it's not !
X-U is already a 100 MHz DSO and has zero optional features to hack.

[balnazzar]

But it's not !
X-U is already a 100 MHz DSO and has zero optional features to hack.

Didn't know about the zero optional hackable feature, but I took a hacked 1054Z for granted.

[nctnico]

That 1.2Gs/s is not for real. The actual samplerate for the SDG2k units is 300Ms/s

Two questions:
1. Why do they declare 1.2 GSa/s?

Due to some trick to smooth the output. But this doesn't work for all signals.

2. Is the actual sample rate of the 1000X even lower?

I don't think so. The real samplerate is typically mentioned for the maximum samplerate that can be used for arbitrary waveforms.

[alm]

Used equipment: considered. But if you read here and there, for example a known problem of the AD/AD2 is the fragilty of the micro-USB connector. If you aren't careful, it will get broken or partially broken very soon. A lot of people on forums lamented that having purchased an used one, they found the connector 'working' but basically broken and sloppily repaired.. And too few vendors on ebay offer the return option, not to mention the hassle.

Well, people generally won't post to complain their USB connector is working fine . FWIW, I bought both an AD2 and Digital Discovery used on eBay a while ago, and the USB connector is fine on both (n=2). You can often see from the state if a unit has barely been out of the package or has been used in class every day for months.

[Martin72]

That 1.2Gs/s is not for real. The actual samplerate for the SDG2k units is 300Ms/s

Two questions:
1. Why do they declare 1.2 GSa/s?
2. Is the actual sample rate of the 1000X even lower?

Thanks!

1. 1.2 GSa/s is 4-times interpolated, see datasheet
2. 150MSa/s

[rf-loop]

https://siglentna.com/application-note/interpolated-dds-technique-sdg2000x/?pdf=2817

[mawyatt]

Excellent description of interpolative DDS techniques shown above in the App Note. Believe this technique is employed in both the SDG2000 and SDG6000, which both produce excellent quality waveforms.

Best,

[Martin72]

Yeah, even me have understand it...

[balnazzar]

I got the AD2 yesterday. I'm fooling around with it, so far i like it

I think I just need a flat cable to connect the BNC adapter to the AD2, otherwise the connector won't last long (hoping that the cable won't add too much crosstalk..).

One thing I don't like is indeed the fragility of the stuff  . I don't know how they could use them in university labs and not having them broken the first day by the students.

I should get the get the little Siglent today, will keep you posted.