That's a much longer rise time. Here's my scope's built-in AFG with the TPP0500B probe showing a rise time of about 4 ns:
View attachment 53712
So it’s the generator fault.
That's a much longer rise time. Here's my scope's built-in AFG with the TPP0500B probe showing a rise time of about 4 ns:
View attachment 53712
No, especially as my 'scope has a bandwidth of 40MHz, but what I do not understand, and that's my fault, is what's the point of this thread?I doubt your cheap probe can measure a rise time of less than 2 ns, which is what we're looking at here. The distortion is probably the result of interactions between the probe capacitance, source impedance, and PCB + probe ground inductance.
but what I do not understand, and that's my fault, is what's the point of this thread?
S
Have fun? Remember the motto of ASR?No, especially as my 'scope has a bandwidth of 40MHz, but what I do not understand, and that's my fault, is what's the point of this thread?
I thought someone here might find it interesting. Feel free to ignore it. I won't be offended.what's the point of this thread?
I do. Keep posting.I thought someone here might find it interesting. Feel free to ignore it. I won't be offended.
How are you grounding the probe? It can make a big difference to things like those ripples.Found a better source: SPDIF output of RME ADI-2 PRO fs. Not terminated with 75 Ohm though, this may explain the ripples.
50 ns/div:
View attachment 53715
5 ns/div:
View attachment 53716
A risetime of 5.5 ns is not too bad. Still unknown whether the probe or the source is the limit though.
The ca 10 cm long wire. You're correct, I should try something shorter ...How are you grounding the probe? It can make a big difference to things like those ripples.
Ah, you're having fun? Now I understand, I think.Have fun? Remember the motto of ASR?
This probe?I thought about digging up a shot from work showing <20 ps edges on a 70 GHz DSO, or the edges from one of our 30 GHz (slow) dif probes, but then remembered this is an audio forum...
Sounds expensive.I thought about digging up a shot from work showing <20 ps edges on a 70 GHz DSO, or the edges from one of our 30 GHz (slow) dif probes, but then remembered this is an audio forum...
Yup. We have a number of them, along with the earlier 25 GHz version. And a ton of other probes as well, natch.
Sounds expensive.
Derp. Sorry.Too lazy to read? It's written at the bottom of each screenshot: 24.5758 MHz.
...
I missed that too, but my excuse is that I've never used a digital 'scope, so those numbers at the bottom meant nothing to me. My first 'scope was a Cossor 1049 with a 100kHz (not MHz or GHz) bandwidth, http://www.thevalvepage.com/testeq/cossor/1049/1049.htm so even my current 40Mhz 'scope seems advanced.Derp. Sorry.
I saw that, but misinterpreted.
I guess I was thinking/wondering/assuming it was an audio-frequency square wave, and I was pretty disillusioned to see expensive probes (or even cheap ones) struggling to reproduce it.