Author Topic: R&S RTC1002  (Read 3486 times)

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Offline Mivera

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Re: R&S RTC1002
« Reply #125 on: September 21, 2019, 06:47:18 pm »
From what I understand these low noise amplifiers are very expensive. Such as this one here:

https://www.itm.com/online/teledyne-lecroy-da1855a-series-differential-amplifier?gclid=EAIaIQobChMIy4aFoMni5AIVC9NkCh3TYQIiEAAYASAAEgKupvD_BwE

If you know of anything decent under $2000 please share a link.

I also seen this probe and looked interesting. Has anyone here tried one of these?

https://www.picotest.com/products_PDN_Probe.html

Although I suppose I'll only be able to measure down to the noise floor of the scope with any passive probe. And I'm almost able to do that already with the included probe.


 

Offline maginnovision

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Re: R&S RTC1002
« Reply #126 on: September 21, 2019, 06:56:00 pm »
Here is a cheap adjustable amp.
https://www.alphalabinc.com/product/lna10/
 
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Offline taydin

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Re: R&S RTC1002
« Reply #127 on: September 21, 2019, 07:03:14 pm »
The dscope audio analyzer that you have bought (or will buy, don't remember) will have a noise performance that will be orders of magnitude better than ANY oscilloscope, regardless of price. So why don't you use that for noise measurement?

I have an audio precision ap525 that works up to 1 MHz, and the extra bandwidth is specifically built into this unit to allow troubleshooting power supply related noise issues. For these audio analyzers, ┬ÁV measurement is boring, everyday business.
« Last Edit: September 21, 2019, 07:07:56 pm by taydin »
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Offline Mivera

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Re: R&S RTC1002
« Reply #128 on: September 21, 2019, 07:05:25 pm »
Wow that looks like a good unit for the price. I didn't know they were available for so cheap. I'll buy one and see how low of noise I can measure. I like the 1 Mhz bandwidth filter as well as I don't need to measure over 1 Mhz. Thanks for sharing!
 

Offline Mivera

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Re: R&S RTC1002
« Reply #129 on: September 21, 2019, 07:06:41 pm »
The dscope that you have bought (or will buy, don't remember) will have a noise performance that will be orders of magnitude better than ANY oscilloscope, regardless of price. So why don't you use that for noise measurement?

I have an audio precision ap525 that works up to 1 MHz, and the extra bandwidth is specifically built into this unit to allow troubleshooting power supply related noise issues.

I didn't know I could measure power supply noise with it. Is this possible with the Dscope?
 

Offline taydin

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Re: R&S RTC1002
« Reply #130 on: September 21, 2019, 07:10:57 pm »
I didn't know I could measure power supply noise with it. Is this possible with the Dscope?

You sure can. But the dscope doesn't have the 1 MHz option like the AP, so if you are measuring noise of an SMPS that uses 250 KHz switching, your dscope will be blind to it.
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Offline Mivera

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Re: R&S RTC1002
« Reply #131 on: September 21, 2019, 07:16:27 pm »
How do I do that? I know any power supply noise that makes it to the analog or digital outputs of my audio gear that's under 200khz will show up. But I can also connect the supply up directly to the XLR inputs?

The new dScope M1 matches the aPX525 with the precision oscillator option in THD+N. -110dB. But limited to 200Khz. However I still plan on using the scope to measure class d amps, and anything over 200Khz. Which was another use for this scope as I didn't think 200Khz-1Mhz ability of the aPX-525 was worth the $15k price premium.
 

Offline Mivera

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Re: R&S RTC1002
« Reply #132 on: September 21, 2019, 08:12:28 pm »
Just found this app note but doesn't say if the supply can be connected directly to the analog inputs.


https://www.ap.com/technical-library/designing-switching-power-supplies-with-apx/
 

Offline egonotto

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Re: R&S RTC1002
« Reply #133 on: September 22, 2019, 05:54:34 am »
Hello,

you can lower your noise level about a factor 1.4 if you add both channels.

The signals in the sum is doubled, but the noise is only about 1,4.


 
Best regards
egonotto
« Last Edit: September 22, 2019, 05:57:08 am by egonotto »
 
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Online borjam

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Re: R&S RTC1002
« Reply #134 on: September 22, 2019, 08:06:05 am »
Regarding the RTC1K-COM2 package, it is a great deal. However after thinking hard it is $700 more CND, and I can already do everything I need to do with this scope. If down the road I need more capabilities, I will buy a higher end R&S scope and put it in a different station. This one will be perfect for full time use in the power supply QC station for decades.
I am sure the R&S is amazing for the price, but the price (including options) is still several times the price of the  SDS1202X-E. I own the Siglent and the Rigol DS1074Z and the Siglent is much better in input noise, responsiveness, etc.

If you compare teardowns of, for example, sort of "competing" Siglent and R&S models (example, Siglent and R&S FPC1500 spectrum analyzer) you will see a better construction in the R&S case. Especially if you compare it to the spectrum analyzer+VNA I have: SVA1015X which cuts some corners in order to lower the price.

Still: these cheap Chinese instruments are useful as long as you know how to use them and, of course, you are aware of their limitations. Again, same applies to the best in class ones. Although I got them for hobby use I have used both the Siglent and Rigol scopes to solve several problems at work and, indeed, I avoided a lot of stupid debugging time. Both instruments did their job perfectly given my requirements.

The good thing is: Before these Chinese manufacturers began to mature, you could only rely on second hand equipment for hobby use, which could be hit or miss. Now there is an entirely new price class which, again, is not the same as the higher end products made by manufacturers with half a century of experience behind, but  can work very well for many purposes.

Glad you are happy with your new scope. Now it's time to become familiar with its capabilities and limitations :)
 
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Offline Mivera

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Re: R&S RTC1002
« Reply #135 on: September 22, 2019, 02:20:09 pm »
Hello,

you can lower your noise level about a factor 1.4 if you add both channels.

The signals in the sum is doubled, but the noise is only about 1,4.


 
Best regards
egonotto

I think the bottleneck here is common mode noise interference rather than the noise floor of the scope. I'll try that amplifier and see if I can get better results. However the results I'm already getting exceed what I was expecting to achieve with this scope. For extreme low noise measurements, I'm going to need a much more expensive setup such as the R&S RTO combined with their ZPR20 probe. Details in here:

https://cdn.rohde-schwarz.com/fr/general_37/local_webpages/RS_ScopeDay_March2017_Power_Integrity_measurements.pdf

 

Offline Mivera

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Re: R&S RTC1002
« Reply #136 on: September 22, 2019, 03:52:52 pm »
I'm not sure if this is a standard feature in all scopes. But I discovered I can take a sweep and it saves the sweep in memory. Then I can go into the acquire filter settings and change the low pass filter right from 50Mhz, all the way down to 2.5hz, and observe the difference in noise. No need for multiple sweeps as it applies the filter to the data saved in memory. It's pretty cool and didn't know I could do this.
 

Offline Mivera

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Re: R&S RTC1002
« Reply #137 on: September 22, 2019, 04:28:11 pm »
Does anyone know the best BNC cable to use between the LNA10:

https://www.alphalabinc.com/product/lna10/

And my scope? I bought some 50ohm adapters as well:

https://www.digikey.ca/product-detail/en/cal-test-electronics/CT2944C-50/CT2944C-50-ND/9826334

Would it be best to use them on the scope input, or probe inputs of the preamp?
 

Offline Mivera

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Re: R&S RTC1002
« Reply #138 on: September 23, 2019, 12:18:57 am »
Regarding the RTC1K-COM2 package, it is a great deal. However after thinking hard it is $700 more CND, and I can already do everything I need to do with this scope. If down the road I need more capabilities, I will buy a higher end R&S scope and put it in a different station. This one will be perfect for full time use in the power supply QC station for decades.
I am sure the R&S is amazing for the price, but the price (including options) is still several times the price of the  SDS1202X-E. I own the Siglent and the Rigol DS1074Z and the Siglent is much better in input noise, responsiveness, etc.

If you compare teardowns of, for example, sort of "competing" Siglent and R&S models (example, Siglent and R&S FPC1500 spectrum analyzer) you will see a better construction in the R&S case. Especially if you compare it to the spectrum analyzer+VNA I have: SVA1015X which cuts some corners in order to lower the price.

Still: these cheap Chinese instruments are useful as long as you know how to use them and, of course, you are aware of their limitations. Again, same applies to the best in class ones. Although I got them for hobby use I have used both the Siglent and Rigol scopes to solve several problems at work and, indeed, I avoided a lot of stupid debugging time. Both instruments did their job perfectly given my requirements.

The good thing is: Before these Chinese manufacturers began to mature, you could only rely on second hand equipment for hobby use, which could be hit or miss. Now there is an entirely new price class which, again, is not the same as the higher end products made by manufacturers with half a century of experience behind, but  can work very well for many purposes.

Glad you are happy with your new scope. Now it's time to become familiar with its capabilities and limitations :)

Thanks for your insight on the matter. I suppose the good part about this is most Western businesses no longer can afford to buy quality western products anymore because they sold out all of their countries GDP to Asia. So it's awesome that there's cheap options available when you're poor. On the downside the quality isn't increasing to compensate for the shift in wealth. So in the end western countries end up with settling with worse products for what they can afford. Of course this is looking from a perspective of someone with the aspiration of adding to my country's GDP.
« Last Edit: September 23, 2019, 12:24:21 am by Mivera »
 

Offline Mivera

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Re: R&S RTC1002
« Reply #139 on: September 23, 2019, 12:47:01 am »
Every penny of GDP added to China, was a penny that left the Western countries. This is why almost every western country has been on the brink of bankruptcy since 2008. Well except the U.S which has been recovering since the last election. Proof is in the attachment. Kinda mirrors when Chinese scopes started getting cheap doesn't it? So what price are we really paying??
« Last Edit: September 23, 2019, 12:55:01 am by Mivera »
 

Offline Mivera

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Re: R&S RTC1002
« Reply #140 on: September 23, 2019, 03:20:56 am »
I suppose I should add that the Chinese GDP data may show that the country is doing well. But what it doesn't show is 99.99% of that GDP is going into the pockets of 0.001% of the population. While the 99.99% live and work in horrible conditions, making less than $2 per day.  The standards for living and pollution are absolutely horrible. they dump raw unfiltered toxins into the rivers and the air. Most people don't even walk the city streets without masks on to filter the pollution. But they don't actually do anything. It would take a full blown respirator to filter that horrible air to safe levels. Who's going to wear those 24/7?

But the Western attitude is "hey but we're saving a few bucks aren't we........"

« Last Edit: September 23, 2019, 03:34:35 am by Mivera »
 

Offline maginnovision

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Re: R&S RTC1002
« Reply #141 on: September 23, 2019, 04:57:51 am »
It's not advisable to get into politics on this forum, especially not here in Test Equipment. I would suggest deleting both of the China replies.
 
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Offline Mivera

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Re: R&S RTC1002
« Reply #142 on: September 23, 2019, 05:02:49 am »
Personally I feel if supporters of Chinese gear can come and crash this thread, it should be fine if supporters of western gear can state their opinion as well. Yes I can see how this could possibly be disruptive to some distributors who use this forum as a sales platform. But the way I see it, nobody who sells gear that isn't an interested civilian in the gear discussed, and is actually a salesman of other gear, should stick to their own threads.
« Last Edit: September 23, 2019, 05:12:46 am by Mivera »
 

Offline maginnovision

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Re: R&S RTC1002
« Reply #143 on: September 23, 2019, 05:06:10 am »
Talking about the gear is fine, but those two replies were about china and little else. It's up to you though, I'm not one to report anything but spam.
 
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Online 2N3055

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Re: R&S RTC1002
« Reply #144 on: September 23, 2019, 08:30:21 am »
Fact that you a Sinophobe was clear from the start, blindly trumpeting virtues of "good Western" equipment...
West makes plenty of crap worse that China, but fraudulently slap some fancy brand on it and by claiming some purported quality that just isn't there.
Chinese are at least honest to charge honest prices: cheap for crap, and a bit more for good stuff.

So like maginnovision nicely said, hate who you like, that's your basic right, just not here....

What supporters of chinese and western gear? Any engineer that supports gear based on country of origin and not technical merits is nationalist, not engineer..
People on this forum like to call things bad or good based on technical merit and not on nationalism..
Most of us hang here exactly because of that, because we are fed up with that crap in mainstream media...

If you want nationalist crap go to Breitbart.com. Here we like to discuss MHz and mV.......
 
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Online SilverSolder

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Re: R&S RTC1002
« Reply #145 on: September 23, 2019, 02:14:50 pm »
Hello,

you can lower your noise level about a factor 1.4 if you add both channels.

The signals in the sum is doubled, but the noise is only about 1,4.
 
Best regards
egonotto

Cool trick, I like it!
 
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Online 2N3055

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Re: R&S RTC1002
« Reply #146 on: September 23, 2019, 02:40:05 pm »
Hello,

you can lower your noise level about a factor 1.4 if you add both channels.

The signals in the sum is doubled, but the noise is only about 1,4.
 
Best regards
egonotto

Cool trick, I like it!
It is nice..
A bit more on the topic.
 
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Offline Simon

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Re: R&S RTC1002
« Reply #147 on: September 23, 2019, 03:13:31 pm »
Can we get back to the topic please!
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Offline Mivera

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Re: R&S RTC1002
« Reply #148 on: September 23, 2019, 05:25:33 pm »
There would have been no talk about China or Chinese gear had everyone discussed the scope the thread was made for. The topic is R&S RTC1002, not which Chinese scopes are cheaper than the R&S RTC1002. So moving forward hopefully we can stick to the thread topic. And maybe someone else that actually owns one will chime in at some point.
 

Offline Simon

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Re: R&S RTC1002
« Reply #149 on: September 23, 2019, 05:43:24 pm »
There would have been no talk about China or Chinese gear had everyone discussed the scope the thread was made for. The topic is R&S RTC1002, not which Chinese scopes are cheaper than the R&S RTC1002. So moving forward hopefully we can stick to the thread topic. And maybe someone else that actually owns one will chime in at some point.

Erm? go 2 posts back and reread!
https://www.simonselectronics.co.uk/shop
Varied stock of test instruments and components including EEVblog gear and Wurth Elektronik Books.
Also, if you want to get ripped off: https://www.ebay.co.uk/usr/simons_electronics?_trksid=p2047675.l2559
 


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