Please explain the difference

[Electronics4you]

Hi there

I have data from two test devices:

• Rigol DS1062CD with 200MSa/sec for the logic analyzer, 512kpoints and 16 channels (60 MHz bandwidth)
  
• GW Instek GLA-1016 with 200MHz internal sampling rate, 4Mbits and 16 channels

The simple question is: Which can do the best sampling of a e.g. 40MHz logic signal?

My answer:

The Rigol can save 32k data for each channel. The 200MSa/s corresponds to a sample on each channel every 80ns, and a 40MHz signal on each channel has a time period of 25ns, so this is way to little.

The only difference between the two devices is then, that the Instek can 250k of data for each channel. But that doesn't matter, if the devices alias the 40MHz into a 12.5MHz signal.

I'm I right in my assumptions?

 

[dougy83]

Are you sure that the sampling rate isn't specifying the rate that all channels are sampled at? I'm guessing that the channels are sampled in parallel at the specified sampling rate.

 

[Electronics4you]

That's the problem with the documentation - it does not say that at all. Maybe some members of this forum, have bought a logic analyzer and checked it?