New small scope, this time hopefully with real specs:
- Sampling rate 40MS/s
- Bandwidth 1MHz/18MHz
- Sensistivity 20mV/Div ~ 10V/Div
- Time Base 50ns ~ 10s
- Generator Frequency: 0-500K, 3.0V
- Screen 2.4 inch / Resolution 320*240
- Size 87*58*18mm
http://www.sigpeak.com/productinfo/dso154pro.html
http://www.sigpeak.com/download/ZEEWEII-dso154pro_UserGuide_En.pdf
https://youtu.be/BmaMLNnN-rc
Useless in the real world for checking ripple on a supply rail. Some instruments specify 5mV max ripple, how can you see that with such poor sensitivity.
It appears then that the lower 1Mhz spec for the battery version may be a strategy to encourage the purchase of the more expensive version??
Useless in the real world for checking ripple on a supply rail. Some instruments specify 5mV max ripple, how can you see that with such poor sensitivity.
It's also only single channel and has no bode plot or serial decoders...
An update on the DSO154pro - after putting the function generator through its paces my unit topped out with a max frequency of 1Mhz. Twice the claimed 500Khz spec.
Edit: ni de coña...
I see your screen shows Zeeweii, mine doesn't. Different software versions perhaps? My square wave becomes sinusoidal sooner
...
Textbook stuff.
PS: It can also stop and then zoom out. Take that, Siglent!
You may not know yet but processing all memory available impacts on WFPS rates allowing scopes to miss events.
Unfortunate my probe came faulty.
My scope is 34mhz ? Thanks
I'm sorry, I sent the wrong video
https://youtu.be/D-gZIZkC1Fs
I tested it via sine wave from external signal generator using crocodiles cable. I know that this cable is worse than regular probe but it is only few MHz.
Is it possible I got 1MHz version or something is damaged?
The alligator show square wave better than probe x1 and x10.
(voltage is low because I'm testing battery life and there's only one pixel of battery left...)
I do not know why they attache such probe, but any other probes I have , do not cut bandwith by lowpass filter on x1 position.
Hi, dso154pro there was an update, it mainly added zeeweii icons, there is not much difference in function. Due to hardware limitations, it does not support firmware updates.
Please someone tell me which oscilloscope can show lossless 3mhz square wave? thanks
Got this from the vendor:QuoteHi, dso154pro there was an update, it mainly added zeeweii icons, there is not much difference in function. Due to hardware limitations, it does not support firmware updates.
The scope is VERY likely to support firmware update considering there is an "unused" USB to serial converter chip on board.
This "thing" wouldn't even qualify for a "toy" !!
I agree that the DSO154Pro is excellent for the price, but you do need to be aware of its limitations.
Hi,
I agree that the DSO154Pro is excellent for the price, but you do need to be aware of its limitations.
In this video @ 15:40 the bandwidth of the 154Pro is tested and does just fine @ 18MHz. No where near -3dB.
Hi,
Yes, the analogue bandwidth of the front end is greater than 18MHz.
Because the sampling rate of the ADC is only 40MSa/s, this means that the resultant displayed waveform after sin(x)/x interpolation for a square wave input signal will have ripple before and after the transitions which is not present on the actual signal.
So although you will see reasonable results for high frequency sine wave inputs, for square waves the result is not so good.
If you have sine waves greater than twice the sampling frequency the results will be invalid due to aliasing. For example, a 21MHz sine wave input will be displayed as 19MHz, 22MHz as 18MHz etc..
This behaviour will be the same for all sampling oscilloscopes, but when sampling at say 2GSa/s, the analogue front-end bandwidth will be apparent and interpolation effects will be much less noticeable.
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.
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.
Hi Bill,
If you inject a 22MHz sine wave you will see a stable 18MHz sine wave on the DSO154Pro (as attached).
(Attachment Link)
In this video @ 15:40 the bandwidth of the 154Pro is tested and does just fine @ 18MHz. No where near -3dB.Yes, the analogue bandwidth of the front end is greater than 18MHz.
Hi Bill,
If you inject a 1MHz square wave with a faster edge, you will see more of a difference.
The top trace is a Rigol sampling at 1GSa/s and there is no ripple.
The DSO154Pro is fine, but you may not be seeing a true representation of the signal.
(Attachment Link)
Hi Bill.
If you put a 1MHz square wave into a 20MHz analogue oscilloscope, you will not see the ripple as seen on the DSO154Pro.
Hi Bill.
See below a simulation of a 1MHz square wave with a 100ps rise/fall time passed through a 20MHz low pass filter.
(Attachment Link)
Hi Bill,
No problem.
It is the sin(x)/x reconstruction without any anti-aliasing filter feeding the ADC that screws things up when injecting a square wave with fast edges.
That's why the square wave from the DSO154Pro test generator look reasonable, because it is effectively band limited.
Regards, Dave
The DSO154Pro is fine, but you may not be seeing a true representation of the signal.
I don’t want to repeat all the discussions on sin(x)/x, Gibbs, but in my opinion the displayed waveform is not always representative of the input signal.