Invalid waveform

Anything about this unique oscilloscope DIY kit
Post Reply
svmaxi
Posts: 4
Joined: Tue Aug 15, 2017 10:22 am

Invalid waveform

Post by svmaxi »

Hello, please help.
The oscilloscope on a test signal of 10 kHz shows such a picture.
test_signal_10Khz_5v.jpg
Measurements of voltage in control points as in the diagram. At the point VB +0.33 V instead of +0.6 V.
The device is programmed with 061 firmware from the site through the J4 connector.
Prompt this software or hardware error. What could be the malfunction?
P.S. The device worked fine before the firmware.
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Invalid waveform

Post by jye1 »

Can you change timebase to 50us or so and try again? For 10KHz signal 10ms timebase is too slow. The waveform could be false due to the low sampling rate.

VB being 0.3V is too lower. This voltage is independent to firmware. It is suggested to double check if it was correct before you changed the firmware.
svmaxi
Posts: 4
Joined: Tue Aug 15, 2017 10:22 am

Re: Invalid waveform

Post by svmaxi »

Here are new measurements
20ms
20ms
20ms
50ms
50ms
50ms
0.1s
0.1s
0.1s
And this shows the working oscilloscope
10ms_work
10ms_work
20ms_work
20ms_work
50ms_work
50ms_work
0.1s_work
0.1s_work
While I did not change the firmware, the VB signal was not measured.
I checked the entire input path there signal is normal. Further ADC converter. I do not know what to do. This is an ADC or processor.
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Invalid waveform

Post by jye1 »

The signal frequency is about 100Hz instead of 10KHz. A different signal?
svmaxi
Posts: 4
Joined: Tue Aug 15, 2017 10:22 am

Re: Invalid waveform

Post by svmaxi »

These are two different oscilloscopes. On oscilloscopes, the signal from the built-in oscillator. And on all dimensions 10 kHz.
svmaxi
Posts: 4
Joined: Tue Aug 15, 2017 10:22 am

Re: Invalid waveform

Post by svmaxi »

And where does the VB signal come from?
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Invalid waveform

Post by jye1 »

VB is one of reference voltage for ADC TLC5510 (U3). It is a DC voltage around 0.6V.
Post Reply