Products > Test Equipment
New toy(?) scope, DSO154pro, 1ch, claimed 40MS/s
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Dave_g8:
For general information, I received a DSO154PPro recently and noticed that the PCB was marked “V1.4”.



This has a few notable differences compared to the previous versions. The changes may be due to component obsolescence, functional updates and/or cost reduction.

- The generation of the negative power supply rail has been modified.
This now uses a similar arrangement to other Zeeweii models, with a switched mode step-up regulator followed by a step-down regulator. This may be to ensure correct behaviour at low battery levels. The large electrolytic decoupling capacitors associated with the previous switching regulator have been removed and since the updated regulators have a higher switching frequency, smaller ceramic capacitors have been used.

- The device used for the data acquisition and waveform generation has been changed.
The device is marked “AG32VF303KCU6”, which appears to be an MCU with a RISC-V core with RV32IMAFC support and should be suitable for signal processing applications.

- The ADC has been changed.
The device is marked “MS9280”, which is a 10-bit ADC. The least significant 2-bits are not connected. There is a minor change in the analogue circuit around the 74HC4051 multiplexer which may be related to the ADC update.

- The waveform generator output circuit has been modified slightly.
The resistor ladder network has been changed to discrete resistors and there are some modifications around the “8091” output amplifier.

I also own a Rigol oscilloscope which is more capable for higher frequency, complex triggering and serial decoding, but the DSO154Pro is still a handy pocket oscilloscope with built in waveform generation and has a quick and simple user interface.

There are freely available 3D printable case models, which I used to provide some degree of protection to the unit.



Overall, for the cost, the DSO154Pro provides excellent functionality and performance compared to other devices in the price bracket.
mojoe:
I'm supposed to get mine on Wednesday. I have four better scopes, but I ordered this to take with me in my carry-on luggage. For use with microcontroller hobby stuff while away from home, this should be sufficient. I could take my HDS272S, but it's much larger, and I pack very light.
mojoe:
My itty bitty scope arrived a day early. I'll do some testing later, after it's charged.

Mine is version 1.3. I don't know if that is good or bad. As we all know, later versions could either be due to improvements or bug fixes, or due to cost cutting where they removed components to save half a cent.

Test results to follow.

Edit: as usual, the charging is not real USB-C.
mojoe:
Test results.

Up to 8 MHz, a 1 Vpp sine wave looks good and measures at 1 Vpp. Beyond that, the voltage starts dropping slowly. I didn't bother looking for the 3 dB point, as from 10 MHz to 18 MHz, everything starts dancing, and the measured voltage isn't stable. At 18 MHz, it's still somewhere around 890 mV, but fluctuating wildly. Beyond 19 MHz, it just won't sync.

As for square waves, at 1 Mhz, the waveform starts to look like Bart Simpson, but is still quite usable. At 5 MHz, you've lost all but the 3rd harmonic, but can still tell it's a square wave.

So, it looks like the bandwidth is actually about 18 MHz, and any harmonics beyond are lost.

Yes, a toy scope, but still quite useful for up to 5-10 MHz, depending on the waveform. For my travel use, it will do nicely. If I drop it or run over it, I won't feel too bad, considering the cost. This would make a nice, inexpensive gift for a budding hobbyist.

Those of us who have been around electronics for quite a while will remember when we wished we could have afforded a boat anchor scope that only did 5 MHz (and you could heat the house with it). So don't sneer too much at this little scope.

Dave_g8:
Hi,
The traces look similar to what I have seen on the V1.4 hardware (see attached), so I expect they are functionally the same.




The ripple on the square wave trace is due to the sin(x)/x interpolation that is used.
A simple example of reconstructing a sampled wave is shown attached.
- Equivalent to 40Msa/s and a 5MHz square wave.
- The red trace is the reconstructed signal



It would be useful to be able to turn off the interpolation in some cases to see the actual sampled waveform, but provided the limitations of the oscilloscope are understood, all is as expected.
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