jajaho / bodeplot Goto Github PK

Sometimes aborting the measurement fails.
So far this has only been observed when aborting from the GUI.
In some cases, this also leat to MATLAB crashing.

• Frequency Response Aquisition via Matlab - FRAM(-App)
• Remote Aquistion of Magnitude and Phase via Matlab - RAMPlab

caching instrument properties could improve performance and minimize queries.
How about that?

visadev has been introduced in R2021a and visa will be removed in future releases.
However, it is seems like this requires additional support packages-

links:
https://de.mathworks.com/help/instrument/transition-your-code-to-visadev-interface.html
https://de.mathworks.com/help/instrument/visadev.html
https://de.mathworks.com/help/instrument/visa.html

The problem is independent of frequency.

• subtract offset voltage

Previously the output was disabled before changing printing the new frequency.
This was done primarily because it seemed like the new frequency setting was read by the instrument successfully, but had no effect on the output.

I have now removed this toggling of the output to reduce wear on the relays.
So far the frequency setting seems to affect the signal output correctly, but a new problem has emerged:

The built-in autoscaling of the scope is now struggling to display the signal correctly which results in invalid voltage and phase readings. But only for the first one to four readings. This was taken with eas on.
This problem only occurs sporadicly.

The accuracy of a measurement depends on the combined accuracy of the instruments used as well as on the quality of the setup.
I have found that with my instruments, namely a fully upgraded DS1054Z with 100 MHz bandwidth and 24 Mpts (so technically a DS1104Z) as well as a stock DG1022Z I can achieve the following results up to 10 MHz:

Magnitude/Attenuation, maximum error: better than (pm) 0.3 dB
Phase, maximum error: better than (pm) 0.1 rad

Setup:
1 m RG58 coax from output 1 into a t-splitter mounted directly to ch1 of the oscilloscope and whose other end connects to a 30 cm RG58 coax and into ch2. The cables are from good quality manufacturers but I fished them out of my universities dumpster so there is a good chance that something is wrong with them.

As you can see on the plot above, for frequencies above 10 MHz the magnitude rises up to 1 dB for 25 MHz.
I have jet to figure out what exactly causes this behaviour.