... and need to be able to look at 10–1000 mV pulses with a rise time of 1.5–3 ns ...
Are you concerned only with pulse-pair resolution (how close the pulses can be while still resolved as separate) or do you need other information about pulse width, pulse height, or rise time?
... and need to be able to look at 10–1000 mV pulses with a rise time of 1.5–3 ns ...
You should be a bit more explicit about what you mean by "look at". In particular, what aspects of the pulses will you be measuring and what are the fidelity requirements. You will be able to see a pulse is present and its relative time of occurance even with a 50MHz scope
Having said that, the key points are indeed the risetime and amplitude.
The rule of thumb is that tr=0.35/BW, where the risetime and bandwidth are the combination of the scope plus probe plus signal. Hence 1.5ns=>250MHz.
The rule of thumb is that the risetimes increase as root-sum-of-squares, so the combination of two components with a risetime of 1.5ns is 1.414*1.5ns.
That should give you sufficient information to enable you to determine the required scope+probe bandwidth.
Given that bandwidth and the impedances, you should be able to calculate the noise. The noise won't be trivial, but may well be OK - depending on your fidelity requirements.
I work with electron multipliers and need to be able to look at 10–1000 mV pulses with a rise time of 1.5–3 ns and a total pulse width of ~20 ns.
For example, I am wondering if I should consider buying a slower Tektronix scope for daily/high voltage use and something less nice to use but with the necessary bandwidth for this one specific job. I'd be much happier spending around $5000 if I can get away with it.
You need something with low front end noise so you can use the 5mV/div setting with a 10X probe. If your source is low-impedance and you can use a 10X or 20X low-impedance probe with a 50 ohm scope input, that will work even better. You also need 350MHz+ bandwidth. I have a Siglent SDS2354X+ and a Tektronix P6156 10X probe (among others) and I would easily be able to get a very clear picture of a signal like the one you're describing. As far as being "nice to use", I think it is probably more of becoming familiar with it more than it actually having a bad UI.
If you can get used to a touchscreen it's actually fairly nice to operate.
although you'd have to say exactly what your "high voltage" application and requirements are to make sure the appropriate probes are available.
That's definitely something I'm not excited about,
I no longer intend to measure high voltage RF, so I only expect to have the need to measure DC high voltage up to 20 kV to look at flutter and drift on pedestrian timescales (like kHz or slower). I think anyone will have a single-ended high voltage probe that I could get away with for this.
39kV 1000:1 2pF 50 MHz 900M HVP-39pro fits the bill.
39kV 1000:1 2pF 50 MHz 900M HVP-39pro fits the bill.
39kV 1000:1 2pF 50 MHz 900M HVP-39pro fits the bill.
Make sure the voltage vs frequency derating curve is acceptable
39kV 1000:1 2pF 50 MHz 900M HVP-39pro fits the bill.
Make sure the voltage vs frequency derating curve is acceptableOP states:
like kHz or slower
39kV 1000:1 2pF 50 MHz 900M HVP-39pro fits the bill.
Make sure the voltage vs frequency derating curve is acceptableOP states:
like kHz or slower
FWIW, as an example, here's what I am able to capture with a Rigol DHO804 tricked into thinking that it's a DHO924. Cost $342.16 at the time of purchase, but I did use some Aliexpress sale coupons active at that time.
Hi,
Good pulse response is not possible with passive probes.
I have several 500MHz probes and none of them have as few abberations as a good coax connection.
Coax type
If possible, then always use good 50 Ohm coax, normal RG58 is not good enough for correct pulse response.
Bandwidth
I am thinking more of a 500MHz model scope with at least 2GHz sample frequency.
My 2 cents :-)
Kind regards,
Bram
39kV 1000:1 2pF 50 MHz 900M HVP-39pro fits the bill.
Make sure the voltage vs frequency derating curve is acceptableOP states:
like kHz or slower
Yes. So?
Hi,
Good pulse response is not possible with passive probes.
I have several 500MHz probes and none of them have as few abberations as a good coax connection.
Coax type
If possible, then always use good 50 Ohm coax, normal RG58 is not good enough for correct pulse response.
Bandwidth
I am thinking more of a 500MHz model scope with at least 2GHz sample frequency.
My 2 cents :-)
Kind regards,
Bram
Depending on what you read, brands like Rigol are either a great value and pretty decent to use for anything that doesn't require critical calibration/certification, or are lousy, buggy, and failure-prone pieces of junk with terrible UI. Seems like there's a missing middle for my part of the market, which I know is true for lots of sectors (microscopes come to mind).
The multiplier pulses I would always be measuring with a coax connection directly to the scope, but maybe I should be thinking more carefully about how I split the signal when I need to do this with the other electronics still attached.
I work with electron multipliers and need to be able to look at 10–1000 mV pulses with a rise time of 1.5–3 ns and a total pulse width of ~20 ns.
A sub-$500 oscilloscope will easily see those pulses.
Thanks, this is interesting . . . I am not sure what to make of the budget vs. quality brand debate for this particular purchase. Depending on what you read, brands like Rigol are either a great value and pretty decent to use for anything that doesn't require critical calibration/certification, or are lousy, buggy, and failure-prone pieces of junk with terrible UI. Seems like there's a missing middle for my part of the market, which I know is true for lots of sectors (microscopes come to mind).
A brands only have edge in higher end, where they have 20+GHz scopes and likes of LeCroy who have miles and miles of all kinds of advanced analysis nobody else has (not even other A brands).
Age of total supremacy of A brands is gone. Now they have edge only in super sophisticated products.
And that is not because legendary A brands couldn't keep the step. It is because their MBA managements only want to manufacture products where they have no competition. That way you can have predatory pricing and numbers look impressive.