Hi guys!
I got my long expected OWON VDS1022 without the letter "I"!
I also got a set of extra parts ADUM3160 and
DCP0205, which was ordered by Aliexpress. After removing 8 SMD short jumpers, i soldered these chips in place and got a working model VDS1022I
A photo of the board before the upgrade i attach to my message.
Next i installed the software version 1.0.23, which with the kind help of respected
Gyro and
camomille i supplemented with Russian language, beautiful icons and which i very much like!
Sorry about my English, i 'm using a translator!
Next, i decided to test the actual bandwidth of the oscilloscope input path. For this purpose I used a professional Russian high-frequency generator Г4-148 (100MHz) and a load of 50 ohms.
Just to follow up, I ran a frequency scan today as I indicated. I used an Adret 730A synthesized sig gen with 50 ohm through-terminator directly at the scope input. At 1Vrms signal level. Averaging was turned on:
Channel 1 was -3dB at 34.7MHz
Channel 2 was -3dB at 31.2MHz
My oscilloscope has about the same bandwidth of up to 32 MHz in both channels. This can be seen in my screenshots.
Next, I wanted to check how accurately the instrument measures AC and DC voltage, how accurate the calibration is, and can you trust the readings of this item?
I gave the instrument 30 minutes to warm up and stabilize the temperature and then did the calibration procedure via the Utilities menu.
To begin with, I connected the inputs of the CH1 and CH2 test probes to the output of the calibrator 5V 1kHz. Also to monitor the voltage level at this output, i connected my Brymen867. As you can see in the photo, the oscilloscope measured Vrms and Vpp quite accurately. The divider on the probes was in position x10. Next, i switched the divider to position x1 and connected my sample DC voltage source, which is assembled on the available chip AD584, to the test probes.
First I measured the 2.499V voltage at the 1V/del limit. The default calibration is pretty well tuned, I didn 't adjust anything extra. Vtop=2.480V for both channels.
Then I measured the same voltage at 500mV/del. Vtop=2.360V for CH1 and Vtop=2.340V for CH2, CorseGain=0.962(1) and CorseGain=0.965(2)
I changed the values CorseGain=0 .973 (1) and CorseGain=0 .976 (2). I then saved the calibration values with the SaveCalibration button and the measured voltage became Vtop = 2.480V for both channels. Next I measured the voltage 5.00V,7.50V and 10.00V and got quite convincing results. This is not bad for this class of USB oscilloscope!
Now I have a few questions about the design of the program interface. By what principle do you select the red beam color for the first channel and the yellow beam color for the second channel? Is it possible to change this palette to another palette? I would prefer to have a green beam on the first channel, as on an analog instrument.
In this shell, the green color has an FFT operation.