High-speed waveform averaging on the Red Pitaya

[Hawkes]

Hi,

I would like to use the Red Pitaya for the following task: Acquiring up to 50000 samples from the ADC @ 125 MS/s when a trigger event occurs. The acquired waveforms should be averaged (added) in a buffer and transferred to a connected PC after the acquisition has finished. The trigger rate can be between 1 kHz to 10 kHz. Can someone give me a hint how to implement this task with the Red Pitaya?

[pavel]

I'm doing something similar in my scanning system project. I'm using an accumulator IP core to sum a configurable number of ADC samples. In this project, the trigger signal is generated internally but it shouldn't be very difficult to replace it with an external trigger signal.

[Hawkes]

Ok, it seems that I finally have to learn FPGA development. Maybe one could also do this with a modification of the axi_code from Nils Roos?

I will have a look.

[jerzydziewierz]

to acquire 50k samples AND do processing on them, there could be several approaches,

the one most promising at the moment is,

take the rp_remote_acquire module, modify it so that it supports trigger that simply zeroes the write-to-location pointer,
then use a second buffer and ask the CPU1 to accumulate the samples into it once you get a hint that acquisition has finished.
use a second thread on CPU0 to monitor the entire process and communicate the accumulator-buffer to the host.

Sounds easy, but that's easily a few weeks of work.
Welcome to the world of instrument prototyping let us know if you undertake to do this this at all. To be honest, using a real oscilloscope will probably save you money overall . . . . RP's real power is in doing signal processing of the kind that you cannot find off-the-shelf (e.g. 50MHz PID, or 30MHz SDR), and of course, that it is cool DIY