Afonso Teles

As Jeff said, the record length can be configured on the scope horizontal/acquisition menu, not on DPOJET.

For clarification, the record length is the number of points saved to memory per acquisition. That is to say, a 250 M record length implies that 250 million points are saved to memory per acquisition (the duration of the acquisition being 10 times the configured scale or time/div).

Hi Andre,

You are doing nothing wrong, unfortunately this is currently a known gap in the 2 series MSO.
I have escalated this to our product line team and we are hoping to fix this in upcoming firmware releases.

Hi Jeremy,

The only way I've found to get the units of a math channel when those aren't custom is display:waveview1:cursor:cursor1:hbars:aunits?, this will query the units of the currently selected waveform view. To select a waveform, view you can do display:waveview1:cursor:cursor1:asource math2.

Cursors do not have to be enabled for this work.

Note this will only get you the unit, not the scale, for that you can use the commands we previously discussed.

Hi,

As a starting point I would suggest looking at the following remote control examples: https://forum.tek.com/viewtopic.php?f=580&t=133570
If you have yet to pick a language to use, then I generally suggest Python3.

Those examples might not do the specific things you need, for that you will need to consult the programmer's manual and find the commands you need: https://www.tek.com/en/oscilloscope/mso4000-dpo4000-manual/mdo4000c-mdo4000b-mdo4000-mso4000b-dpo4000b-and-mdo3000-0
To turn on a channel and configure it to full bandwidth, look in the Vertical command group.
For triggering setup, look in the Trigger group. 
For setting up measurements (which can be made visible on the screen), look into the Measurements group.

Hi,

The TDS2000B service manual lists step 33 (page 5-7) as 1.0 V, not -2.5 V.

Hi Jeremy!

The MATH:MATH2:VUNIT? command returns the name of the "Alternate Units" (empty by default, in which case V is used).

I believe the command you are looking for is display:waveview1:math:math2:vertical:scale? or MATH:MATH2:SCALE? (not mentioned in the manual but appears to be equivalent).

Hi Jeff,
Yes, there is a significantly newer version of DPOJET available.
DPOJET is updated together with the firmware of the machine. Here is the latest version of the firmware (and DPOJET): https://www.tek.com/en/support/software/firmware/firmware-dpo7000-dpo-dsa70000-dpo-dsa70000b-c-mso70000-c-doc-win-xp

On measuring relative jitter between two clock source's, that is possible by selecting a measurement like TIE, RJ or DJ, then going into "Configure", "Clock Recovery" and setting the Method to "Explicit clock - Edge" and selecting the desired clock channel.

There was a known problem with measurements on the TBS2000X.
This has been fixed with the latest firmware release. I ask that you install it and try again: https://www.tek.com/en/support/software/firmware/tbs2104x-firmware-release-v132136

"curve?" data from spectrum view should always be in 8 byte floating point format, so data:width doesn't need to be set explicitly.

Vrms is a measure of the voltage integral adjusted to allow for easier measure of power.
dBm is a measure of power relative to 1 mW.
The relationship between them is giving by the usual P = V^2/R relationship. The dBm display on spectrum view assumes a 50 Ohm load, this may or may not be true.

The fact the first harmonic is at ~13.5 dBm comes from the inherent properties of applying the Fourier transform to a square wave. I will not go through the math here, but there are plenty of sources discussing the Fourier transform of a square wave.

I do not know how your LabVIEW program works, but I assume you simply passed it the data from the "curve?" command to a plotting function.
It then picked the highest point as 0 dB (not dBm). This explains what you are seeing.
This seems like a quirk of how the LabVIEW plotting function works.

Hi,

The lowest measurable frequency is the inverse of the acquisition time (which is ten times the time/div). This means that to get measurements for lower frequencies, you should increase the time/div.
To do this you can go into the Horizontal/Acquisition menu and set the Horizontal mode to Manual and then increase the record length (increases processing times) or, if that isn't enough, the sample rate. Make sure not to drop the sample rate to the point that it might cause aliasing of your signal. In your specific case, the sample rate should stay at 25 MS/s and above.

Measurements down to ~10 Hz should be possible, with 25 MS/s sample rate and 250 M record length.