Reading downsampled data from the MDO34

I'm sorry if this is a stupid question but I'm used to this being easy and I can't figure it out with this scope.<br> <br> I'm reading waveforms from an Tektronix MDO34 that do need the full 2.5GSps sampling rate. The ethernet communication is very slow if I read the entire waveform at that rate so I'd prefer to read every 25th sample to get it at 100MSps. With other equipment I have a divisor or sparsing factor that I can set to make this easy.<br> <br> From the front panel I can see setting the record length affects the sample rate although it seems the finite number of choices does not give me 100MSps. I have tried using &quot;:hor:reco &lt;num_points&gt;&quot; and &quot;:wfmi:xin &lt;sample_period&gt;&quot; to have the desired effect but what I read is not my waveform.<br> <br> Can anyone help me figure out how to achieve this task with this (and I assume all) Tektronix scopes?

Hi Robert,<br> <br> The MDO34 does not allow you to manually set the sample rate, it has to be set through a combination of the horizontal scale (<code>horizontal:scale</code>) and record length (<code>horizontal:recordlength</code>).<br> <br> Additionally, if speed is a concern to you, then I would suggest changing <code>data:encdg</code>to &quot;fastest&quot; or some other binary mode. That will result in a significant speedup from ASCII encoding.

Thank you for the reply. Will I get more choices through SCPI for the sample rate than I seem to get through the front panel?<br> <br> For example I want 100MSps but through the front panel I only seem to be able to select record lengths that give me 50Msps or 500Msps.

Hi Robert,<br> <br> The front panel and SCPI commands should both give you all the possible sample rates for the machine.<br> <br> I would suggest manually entering in the desired record length for your chosen horizontal scale and sample rate. I was able to set the sample rate to 100 MS/s and I have attached a picture of that with this post.

Thanks for the verification. Since I was trying to record 25us @ 100MSps maybe my horizontal div setting was what was limiting me to the 50MSps and 500MSps selections on the screen. When I get my scope back from a coworker I'll check for combinations that provide 100MSps like your picture.