Appropriate backend to sample up to 61.44 MSps with no overflow? for AD9361 based platforms

YoussefTRA on Jun 23, 2022

Hello

I would like to sample up to 61.44 Msps with no overflow on my pluto, that is connected to a pc by usb 2.0 so :

1- Whats the max samples in a transport block and whats the max sample rate for contiguous data between blocks (no drops)

since i tried many time, it is probably not possible so:

2- Whats the right transport stream backend? not only for pluto but for all ad9361 based platform (rfsom+fmcomms) ? since if i understand neither usb or ethernet or uart is right for that

3- How does RFSOM and FMCOMMS differ from Pluto in transport size block and contiguous high speed?

4-Can i modify my pluto in some way such adding some interface?

Thanks for reading BR

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mhennerich
Jun 28, 2022 +1 verified
On the Pluto the max sample rate for continuous streaming is limited by the USB2.0 and the libIIO backends.

https://wiki.analog.com/university/tools/pluto/devs/performance

https://wiki.analog.com/resources…

+1 mhennerich

on Jun 28, 2022 9:35 AM
On the Pluto the max sample rate for continuous streaming is limited by the USB2.0 and the libIIO backends.

https://wiki.analog.com/university/tools/pluto/devs/performance

https://wiki.analog.com/resources/tools-software/linux-software/libiio_tips_tricks

The fastest interface is the direct IIO USB backend, or on Linux boxes the CDC-NCM Ethernet mode.

https://wiki.analog.com/university/tools/pluto/users/customizing#changing_the_usb_ethernet_compatibility_mode

There is some libiio2 enhancements underway which should at least double the throughput. (should be available for testing soon)

1) The max throughput depends on the buffer size. 7 MSPS should be possible with the current firmware.

2,3) Gigabit Ethernet is typically faster. On MPSoC with USB3.0 up to 100MB/s should be possible.

4) I don't think so.

-Michael
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0 YoussefTRA on Jun 29, 2022 9:15 AM in reply to mhennerich

Thanks i think i understand enough, according to the performance metrics, 26MB for 32 bit (16*2) is around 6.5 Msps. For the 3rd option:

Via local IIO device (running on Linux inside PLUTO, with self-compiled pv(1))

is there a guide to try some scripts and see the limitations.? i also would like to try external applications but im concerned with memory i dont want to do something wrong and ruin my pluto
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