Rigol DHO814 Sample Rate Not 312.5 MSa/s

[AE5WT]

I have a new Rigol DHO814, 4 Channel oscilloscope. The manual states that 312.5 MSa/s real-time sample rate in all channels mode (3 or 4 channels). However I cannot get it to work anything better than 62.50MSa/s when 3 or more channels are enabled. Is this a bug? I am changing the Memory Depth to try and get the sample rate, but nothing I have done will let me get the 312.5MSa/s no matter if I have 1, 2, or 3 channels enabled.

 

[tunk]

No expert, but it could be related to your horizontal setting (1ms?).
You could try e.g. 1us.

[NE666]

The manual states that 312.5 MSa/s real-time sample rate in all channels mode (3 or 4 channels).

No, it doesn't.

It states "Max. Sample Rate of Analog Channel" (in the specs section / data sheet) and "up to" in the section on the Acquisition system. Note well here the words 'maximum', and 'up to'.

As user 'tunk' has suggested, the *actual* sample rate used is dependent on both memory depth and timebase settings, and will not be maximal for all combinations of settings. Try a faster timebase and see what you get.

[ahsrabrifat]

The sample rate is often affected by the memory depth setting. Your screenshot shows 1M depth selected.  Maybe it is limiting the sample rate.Try to set it to the highest possible value