Best 14-Bit Digital Oscilloscope

[trentender]

Hi,
   I am looking for a low cost (<=£1000 max appoximately) 14-bit digital oscilloscope which can accurately measure and trigger on analogue signals (eg. 100KHz sinewave) down to less than 20uV peak-peak so it needs to be a scope with a very low noise level. Just being 14-bit does not mean that a scope can measure below 20uVpp since the broadband noise generated inside the scope might be at a much higher level than 20uVpp. So does anyone out there know of any great,low cost ,low noise 14 bit digital oscilloscopes which might fit the bill?

Cheers,
Ian

[UK]

You didn't mention a preferable form factor if it matters.

[Sighound36]

Would suggest either of these two dependingon your channel count required.

https://www.picotech.com/oscilloscope/4444/picoscope-4444-overview?lv

https://www.picotech.com/oscilloscope/4262/picoscope-4262-overview

[huababua]

I mean for < 1000 bucks you cant expect a scope with screen.

I am using the TiePie Scope exactly for the noise reason.
https://www.tiepie.com/en/usb-oscilloscope/handyscope-hs6

Within your budget, Scope is okay, SW runs only on windows but API available.

Pico also offers a USB Scope with 16 bit resolution - little bit more expensive.

[trentender]

form factor of the scope not a problem but looking to buy a new scope not second hand

[trentender]

does'nt look too bad,resolution looks like 90uV for the 16 bit scope which is a bit more expensive than I am looking for and a bit noisier than I am looking for but its a lot better than anything I have seen so far so thanks.

[Sighound36]

All of these scopes suggested are new cost.

I have a couple of these and are ideal for what you are sggesting the use is, I have more advanced models, but still use these regularly, the Tiepie is a good alternative option as well.


https://www.picotech.com/oscilloscope/4262/picoscope-4262-overview

[trentender]

I should also have said at the beginning need the -3db bandwidth of the scope to be 100MHz minimum but targetting 200MHz

[trentender]

Looking for something like the OWON XDS3204AE which has a resolution of less than 20uV but unfortunately the background noise is sitting at about 350uV so all that lovely potential sensitivity of the 14-bit ADC is thrown away by poor general design of the scope.

[trentender]

good performance from this scope but its a very low frequency scope (5MHz).

[coppice]

good performance from this scope but its a very low frequency scope (5MHz).

High bandwidth. High resolution. Choose one.

[trentender]

Need both wideband (100MHz minimum) and low noise sensitivity (20uV) and lowish cost.Not asking much I know!!!!!!

[KungFuJosh]

Need both wideband (100MHz minimum) and low noise sensitivity (20uV) and lowish cost.Not asking much I know!!!!!!

You remind me of this meme, but apply it to your scope requirements:



What you really want is significantly more expensive than your budget, so you need to decide which 2 out of 3 (fast, cheap, great) you can live with.

[Performa01]

Need both wideband (100MHz minimum) and low noise sensitivity (20uV) and lowish cost.Not asking much I know!!!!!!

We are used to that.

When talking about signals below about 1 mVpp, one of the very few options would be the Picoscope 4262, as has been already mentioned. It is only 5 MHz, but it is 16 bits and has a noise level of <5 µVrms (~81 µVpp). You seem to expect noise levels below 20 µVpp and for this I wish you luck. Of course, the noise can be lowered even further, by resolution enhancement up to 20 bits and digital channel filters, but all these measures reduce the bandwidth even further.

So, you’re unlikely find any 100, let alone 200 MHz instrument to show 20 µV resolution in the time domain, even if you were willing to spend serious money.

On the other hand, even 8 bit scopes, also with much higher bandwidth than just 200 MHz, with a decent FFT, can measure signals that low in the frequency domain. Yet that doesn’t mean they can distinguish 5.00002 mVpp from 5.0 mVpp, if that’s what you want.

In other words: the 16000 count DMM with 1 count accuracy and 200 MHz bandwidth of is not going to happen.

[KungFuJosh]

is not going to happen.

*with currently available tech. 😉

[nctnico]

My recommendation would be to look for something with differential inputs. A pre-amplifier can also be an option to bypass noise in a cheaper oscilloscope front-end.

[edavid]

Need both wideband (100MHz minimum) and low noise sensitivity (20uV) and lowish cost.Not asking much I know!!!!!!

This is actually impossible.

Referring to a handy noise calculator: https://www.daycounter.com/Calculators/Thermal-Noise-Calculator.phtml

If you plug in 25C, 50ohms, and 100MHz, you get thermal noise of 9uV RMS (about 60uV P-P).

So it's impossible to build a (non-cryogenic) 100MHz oscilloscope with only 20uV P-P (broadband) noise.

[G0HZU]

If you just want to look at sinewaves then you don't need lots of instantaneous bandwidth.

For example, here's a 20uV pkpk signal at 70MHz being fed to my ancient (500MHz BW) 8 bit HP DSO.

To be able to measure it and trigger on it, I've used a precision (2 stage) LNA followed by a 70MHz bandpass filter that is about 10MHz wide. I haven't factored in the loss of the BPF so it shows 18uV pkpk instead of 20uV pkpk, but you get the idea...

The other plots show the flat gain response of the first stage of the preamp. The input VSWR is very low and the noise figure is less than 3dB.

I normally use this precision preamp for noise figure testing, but it can also be used with an oscilloscope to look at tiny RF signals. You can see that the gain response is very flat at 32dB across a huge bandwidth.

[thm_w]

This is actually impossible.

Referring to a handy noise calculator: https://www.daycounter.com/Calculators/Thermal-Noise-Calculator.phtml

If you plug in 25C, 50ohms, and 100MHz, you get thermal noise of 9uV RMS.

So it's impossible to build a 100MHz oscilloscope with 20uV P-P noise.

[mawyatt]

More like 77K, not 25C

Best,

[edavid]

If that's supposed to be liquid nitrogen, it still doesn't get you there.

-196C, 50 ohms, 100MHz -> 5uV RMS -> 30uV P-P

[nctnico]

You can always parallel channels to even out the noise.

[David Hess]

I should also have said at the beginning need the -3db bandwidth of the scope to be 100MHz minimum but targetting 200MHz

That sure is not going to happen.  The old Tektronix 7A22 vertical amplifier has 10 microvolt per division sensitivity, but even at a bandwidth of 1 MHz that is questionable.  Modern parts can do a little better, but not enough.

What could work however is to trigger off of a higher level signal and then use averaging.

You can always parallel channels to even out the noise.

The added parallel input capacitance then limits the bandwidth, so a lower source impedance is required.

[JeremyC]

Hi,
   I am looking for a low cost (<=£1000 max appoximately) 14-bit digital oscilloscope which can accurately measure and trigger on analogue signals (eg. 100KHz sinewave) down to less than 20uV peak-peak so it needs to be a scope with a very low noise level. Just being 14-bit does not mean that a scope can measure below 20uVpp since the broadband noise generated inside the scope might be at a much higher level than 20uVpp. So does anyone out there know of any great,low cost ,low noise 14 bit digital oscilloscopes which might fit the bill?

Cheers,
Ian

[coromonadalix]

ill wait for an 24bit scope  loll