Siglent SDS1104X-E sample rate

[Claus1]

Hello. Could not find fast answer. Does Siglent SDS1104X-E have 1 GSa/s per channel? If so it's not very good, barely covers Nyquist criterion if all 4 channels are used. Same question about SDS1204X-E. Thanks in advance.

[bdunham7]

Both have 2 1GSa/s ADCs so that it has 1GSa/s for one or two channels, 500MSa/s for 3 or 4.  So at 200MHz and 4 channels it has 2.5 samples per period, which "just" meets the Nyquist criteria, I suppose.  Do competing products do better??

[Fungus]

Both have 2 1GSa/s ADCs so that it has 1GSa/s for one or two channels, 500MSa/s for 3 or 4.  So at 200MHz and 4 channels it has 2.5 samples per period, which "just" meets the Nyquist criteria, I suppose.

Not really because the input circuitry isn't bandwidth limited. It has a -3dB point around 300Mhz and there can still be plenty of signal above that.

Do competing products do better??

Rigol DS1054Z has a similar problem - 250Mhz sample rate and -3dB point at around 140Mhz.

To do better you need something like the Rigol MSO5000 which has 2Ghz sample rate for 350Mhz input (four channels on, 8Ghz sample rate with a single channel).

[bdunham7]

Not really because the input circuitry isn't bandwidth limited. It has a -3dB point around 300Mhz and there can still be plenty of signal above that.

All very true, but I was referring only to his question about the sample rate meeting the criteria.  I'm not sure about the 1104X-E as I haven't hacked mine yet, but on the hacked DS1054Z you can get an aliased signal with a 700MHz input--so I would say that neither the input filtering nor the output reconstruction were Nyquist-compliant, even at 1GSa/s.  8-10 samples per period is one way of fixing that, I suppose.

[Fungus]

Not really because the input circuitry isn't bandwidth limited. It has a -3dB point around 300Mhz and there can still be plenty of signal above that.

All very true, but I was referring only to his question about the sample rate meeting the criteria.

And I was saying that the criteria is only valid when the input signal is bandwidth limited.

[tautech]

Hello. Could not find fast answer. Does Siglent SDS1104X-E have 1 GSa/s per channel? If so it's not very good, barely covers Nyquist criterion if all 4 channels are used. Same question about SDS1204X-E. Thanks in advance.

To get to 200 MHz and cover Nyguist comfortably 2GSa/s is recommended so Siglent released SDS2000X-E two channel models of 200 and 350 MHz that offer all the same features of their 4ch X-E range plus added 50 ohm input option for these 2 higher BW models.
https://www.siglenteu.com/digital-oscilloscopes/sds2000x-e/

Also to not impact on storage length with the higher sampling rate the memory depth was doubled to 28 Mpts.
Small thread with further info/discussion:
https://www.eevblog.com/forum/testgear/siglent-sds2000x-e/