Wherever you are on the globe, good morning, afternoon, evening,

Could somebody please tell me what the ‘sub-waves’ in these oscilloscope readings signify in the attached image?

Many thanks,
Gareth

 

Hello,

How are the probes attached to the measured part?
Is the ground correct?

Bertus

 

Please give us some context of what you're measuring, what you expect to measure, and why it deviates from the expected operation... we can't read your mind. Schematics are preferred.

Having said that, some quick thoughts:
1) The frequency of the triangle wave is 0.4Hz
2) The ringing frequency is about 4Hz.
3) These scopes have a lousy sample depth 1kpoints, if I recall correctly, and is being reduced to 512 since you're using channels 1 and 2. Therefore, it could potentially be 50/100/60/120Hz aliasing depending on where in the world you are located.
4) If CH1 is the input and CH2 is the output of a voltage buffer, then you could have instability in your feedback loop. This is a bit more likely since the 4Hz amplitude is greater when CH1 transitions from rising to falling, and vice versa.

 

I see a relatively clean triangular waveform on Channel 1, yellow trace, -2V to 2V amplitude, 2.5s period.

I see oscillations on Channel 2, light blue trace, same voltage and period, 8Hz oscillation or ringing.

How are the scope probe and grounds connected? Is there a source of 8Hz oscillation nearby that can account for the oscillations seen on Channel 2?

 

What is the source of the signal?

Why is the real time clock two and a half years slow?

 

What is the source of the signal?

Why is the real time clock two and a half years slow?

I think the ripple caused the 'scope trace to travel much farther which used more time.

 

I think the ripple caused the 'scope trace to travel much farther which used more time.

Probably it was close to the speed of light.