new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004

[TK]

... it can still display a 1GHz signal...

Very good post!  I'm just curious if anyone knows what would cause just the bottom of the 1GHz wave to appear modulated like that.  I know this is 3x the rated frequency of the scope, just curious why the degradation wouldn't be symmetric vertically.  Shouldn't be aliasing if the wave is purely sinusoildal, given the 2.5Gsps sample rate.  The 500MHz wave looks symmetrical vertically.

Standing wave on the cable perhaps?

It would be nice to see some other frequencies near 1GHz...

[agdr]

It would be nice to see some other frequencies near 1GHz...

I agree!  That might provide some clues.  Poke the system a bit and see how it responds.

[korlatos]

So the effect is definitely there at lower frequencies as well (e.g. 950 MHz), but it is fading as the signal frequency decreases. You can still see it at 800 MHz, but it's pretty much gone at 700 MHz.

I set the signal to 950 MHz and tried three different cables of various lengths, and that definitely had a noticeable effect on the waveform. So, it could be a standing wave issue, as suggested by Mike.

[Joel_l]

Hi,

I took another look at what mine does ( posted some earlier ). I did 900MHz, 1GHz, and 1.1GHz. I did one using single and one running at each frequency. It does get progressively worse as I go up in frequency. I went down to see where it was stable. On my unit, 500 MHz is where it's minimal, 600MHz was very noticeable. I used my Wavetek 2410 as a source connected to the scope with LR400 cable and type F connectors ( adapter on scope end )

Joel

[bktemp]

What happens if you turn on another channel to reduce the maximum samplerate? If you also reduce the input frequency to keep the samplerate/input frequency at the same 2.5 ratio, the waveform should still be ok, if it is only a standing wave effect on the cable.

[nctnico]

This is what happens when sin x/x signal reconstruction stops working. Set the scope to dot mode and it will be fine.

[Joel_l]

I thought maybe you had something, I tried it and it gives the same result. Though I should note, dot mode is in a different menu that acquisition. Acquisition is where you can select Sin(x)/x, Linear, or Sample-Hold. The options other than Sin(x)/x are much worse. It may be that dot mode still uses Sin(x)/x.

This is what happens when sin x/x signal reconstruction stops working. Set the scope to dot mode and it will be fine.

[NA5WH]

Finally got mine in my hands.  And of course had to do something silly with it to start off, just for the fun of it.
(hmm... well not sure how to embed videos on this forum, seems to not like the tags i'm trying to throw at it....  so just a link for now)

[Octane]

Hi NA5WH,

Can you share a few details about this? Software? Source? Files?

Thanks,
Michael

[mtdoc]

Hi NA5WH,

Can you share a few details about this? Software? Source? Files?

Thanks,
Michael

Found in the youtube link:

http://oscilloscopemusic.com

Cool!

[tautech]

Hi NA5WH,

Can you share a few details about this? Software? Source? Files?

Thanks,
Michael

Found it. 

From oscilloscope music artist Jerobeam Fenderson.

This one called Planets:



And can be bought here for 1 EUR
https://jerobeamfenderson.bandcamp.com/track/planets

[JoHr]

I thought maybe you had something, I tried it and it gives the same result. Though I should note, dot mode is in a different menu that acquisition. Acquisition is where you can select Sin(x)/x, Linear, or Sample-Hold. The options other than Sin(x)/x are much worse. It may be that dot mode still uses Sin(x)/x.

Dot mode is an INDEPENDEND setup  versus the interpolation type ...

Interpolstion just care abaout that there is at least one (original or calculated) sample per pixel column.

Dot mode only draws a vertical line between two adjacent points. DOT MODE IS NO INTERPOLATION!!!

[LaurentR]

It's that time again: fan noise.
I was expecting the RTB to be a bit quieter than this given the announced 28dB. I find the noise to be on par with many other instruments but quite tiring (not a nice swoosh - a lot of structure to the sound - probably the fan bearing itself).
Anybody has the same feedback?

When the scope boots, the fan briefly runs at low speed, but then it seems to be running faster the whole time. Is it temperature controlled? There is a yellow wire (PWM?).

Fan swap anybody?

[Hydron]

Yeah fan noise is not as good as I thought it would be either - my initial impressions were in a room with aircon and I thought it was fine, but now it's at home in a quiet environment it's louder than I'd like (though much better than my rigol before it's fan swap).
I also noticed that during boot it runs at different speeds, including a nice quiet one - wish it would pick that speed when the ambient isn't too warm!

I'll have a look at what it's doing with the fan next time I have the cover off.

[Robaroni]

Yeah fan noise is not as good as I thought it would be either - my initial impressions were in a room with aircon and I thought it was fine, but now it's at home in a quiet environment it's louder than I'd like (though much better than my rigol before it's fan swap).
I also noticed that during boot it runs at different speeds, including a nice quiet one - wish it would pick that speed when the ambient isn't too warm!

I'll have a look at what it's doing with the fan next time I have the cover off.

Hydron,
I'm wondering if something isn't right, my scope is dead quiet and I'm very particular about noise. I just  turned everything in my lab off, shut the door to block any outside noise and I have to put my ear up to the scope to hear it. Even then it's not annoying. Could you have jostled it in your travels?
Rob

[Robaroni]

http://www.ebay.com/itm/352053924341?ul_noapp=true

[Joel_l]

Makes sense, guess that means interpolation has nothing to do with the waveform behavior. Makes me think dot mode selection should be in the same acquire menu so that you know you are selecting one or the other.

I thought maybe you had something, I tried it and it gives the same result. Though I should note, dot mode is in a different menu that acquisition. Acquisition is where you can select Sin(x)/x, Linear, or Sample-Hold. The options other than Sin(x)/x are much worse. It may be that dot mode still uses Sin(x)/x.

Dot mode is an INDEPENDEND setup  versus the interpolation type ...

Interpolstion just care abaout that there is at least one (original or calculated) sample per pixel column.

Dot mode only draws a vertical line between two adjacent points. DOT MODE IS NO INTERPOLATION!!!

[ws2812b]

I measured the 300 MHz RTB2004 rise time as 940ps using a Tektronix 284 pulse generator (<= 70ps rise time) and a 50 Ohm Tektronix 011-0099-00 termination.

Yeah: show us your square wave https://www.eevblog.com/forum/testgear/show-us-your-square-wave/350/
Actually wanted to be the first in the other thread myself with that box but I lack a fast enough signal

[ws2812b]

Finally got mine in my hands.  And of course had to do something silly with it to start off, just for the fun of it.
(hmm... well not sure how to embed videos on this forum, seems to not like the tags i'm trying to throw at it....  so just a link for now)

Cool! How did you get the signal on the channels?? Did you teardown an earphone? I want to try the youscope demo. Did anybody try this yet?

[ws2812b]

Yeah fan noise is not as good as I thought it would be either - my initial impressions were in a room with aircon and I thought it was fine, but now it's at home in a quiet environment it's louder than I'd like (though much better than my rigol before it's fan swap).
I also noticed that during boot it runs at different speeds, including a nice quiet one - wish it would pick that speed when the ambient isn't too warm!

I'll have a look at what it's doing with the fan next time I have the cover off.

Hydron,
I'm wondering if something isn't right, my scope is dead quiet and I'm very particular about noise. I just  turned everything in my lab off, shut the door to block any outside noise and I have to put my ear up to the scope to hear it. Even then it's not annoying. Could you have jostled it in your travels?
Rob

Same for me. Cannot hear anything. Might it be that you "changed" something while you altered the defends?

[mikeselectricstuff]

The RTB is easily the quietest thing I have with a fan.

[LaurentR]

Hmm,
thanks for the feedback. Mine is on par for a unmodified DS1000Z or a 3446XA, which is bearable but not great. I am in a non-AC very quiet home.

For those with a quiet scope, do you also notice that during boot, the fan start high for a few seconds, then low for a few more seconds than high again forever?
BTW, just in case there was a firmware-related change, I have 01.204 (newer than on the web site).

[korlatos]

My scope was also quite noisy out of the box, and was also modulating the fan speed on start-up. I took a screwdriver, poked it through a honeycomb opening, and gave the side of the fan a knock or two. That fixed it for me. A side effect of shipping, perhaps?

[TheSteve]

There must be a lot of variation in fan noise. When I had a DS1054Z it was way louder then my 34461A.

Mike, how does your RTB2004 fan noise compare to the MSOX3104T(I find my MSOX3024T to be reasonably quiet).

[Hydron]

Yeah fan noise is not as good as I thought it would be either - my initial impressions were in a room with aircon and I thought it was fine, but now it's at home in a quiet environment it's louder than I'd like (though much better than my rigol before it's fan swap).
I also noticed that during boot it runs at different speeds, including a nice quiet one - wish it would pick that speed when the ambient isn't too warm!

I'll have a look at what it's doing with the fan next time I have the cover off.

Hydron,
I'm wondering if something isn't right, my scope is dead quiet and I'm very particular about noise. I just  turned everything in my lab off, shut the door to block any outside noise and I have to put my ear up to the scope to hear it. Even then it's not annoying. Could you have jostled it in your travels?
Rob

Same for me. Cannot hear anything. Might it be that you "changed" something while you altered the defends?

I haven't modified anything yet - will query the fan noise with R&S and hold off fixing the detents until I get the noise sorted out.