Products > Test Equipment
New toy(?) scope, DSO154pro, 1ch, claimed 40MS/s
BillyO:
An analog scope would just show very close to a sine wave, you might have to educe the frequency from the period.
With my 154, using an 18MHz square wave at 5Vrms from a Siglent SDG1062X and properly terminated I get an apparently amplitude modulated sinusoidal waveform. The amplitude modulation is being caused by aliasing. I don't get that with a pure sine wave, plus it's not getting the amplitude right either (I have the probe setting at 10X so divide by 10). But you can see it's showing the correct frequency. At anything much higher than 18MHz (like 19MHz) it can no longer properly detect the frequency not matter what the waveform.
Aldo22:
--- Quote from: BillyO on March 26, 2024, 02:42:48 pm ---It completely blows away the 5MHz scope I got in 1978 (which I had to build myself) that cost me the equivalent of $1000 in today's money. On top of that it is arguably the best $30 scope you can currently get.
--- End quote ---
That's probably true.
Nevertheless, I would pay a few extra bucks and buy a DSO1511G.
In my opinion it is even better value for money.
https://www.aliexpress.com/item/1005001969702720.html
Dave_g8:
Hi Bill,
If you inject a 22MHz sine wave you will see a stable 18MHz sine wave on the DSO154Pro (as attached).
BillyO:
--- Quote from: Dave_g8 on March 07, 2024, 07:24:24 pm ---There is no evidence of an anti-aliasing filter on the front end of the DSO154Pro which would limit the bandwidth to the ADC, so the results are as expected.
With the in-built signal generator at 1MHz, there is less ringing because the rise/fall time is limited by the waveform generator circuit and therefore the displayed waveform is closer to representing the actual signal.
If the time-base on the DSO154Pro is set to 200us/Div or greater, the sin(x)/x interpolation appears to be turned off. The trace below shows the displayed waveform with the external 1MHz square wave signal. In this case the trace is joining the dots between samples.
--- End quote ---
Yes, and the first case is more accurate.
Below the first image is like yours with the sin(x)/x. The 2nd image is taken with a 600MHz scope using a 750MHz 1.5pF probe, so it is showing the signal being produced by the Zeeweii pretty accurately. It matches what the Zeeweii itself shows pretty exactly.
BillyO:
--- Quote from: Dave_g8 on March 26, 2024, 04:48:25 pm ---Hi Bill,
If you inject a 22MHz sine wave you will see a stable 18MHz sine wave on the DSO154Pro (as attached).
(Attachment Link)
--- End quote ---
Okay, I am not sure what the point is. Are you saying it's not working right if you use it beyond it's specifications? Why would you expect it to?
My Siglent SDS2504 will show a 800MHz signal pretty well, but it's a $3000 scope, not $30.
Zeeweii say the 154Pro is an 18MHz scope and it meets this specification. What more do you need? :-//
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