Known issues.

[Apollo3zehn]

• Source = FT + RAM writer throttle > 0: This leads to a deadlock because the throttler waits for the assertion of S_AXIS_tvalid to forward M_AXIS_tready to S_AXIS_tready and at the same time the averager (part of FT) waits for S_AXIS_tvalid to be able to continue averaging process. If S_AXIS_tvalid is not asserted, the state cannot change to state == first, which means that S_AXIS_tvalid is not asserted. Deadlock. Solution: disallow throttling of FT because it is useless anyway.

if (S_AXIS_tvalid) begin
    if (count >= max - 1) begin
        count_next      = 0;
        deny_next       = 1'b0;
    end else begin
        count_next      = count + 1;
        deny_next       = 1'b1;
    end
end

• The Fourier Transform must be started before the RAM writer is working to ensure buffer alignment. Also both modules must be reset and restarted after change of buffer size.

• If the bitstream is replaced during a burst operation of the RAM writer, the theory is that due to the unfinished burst, there is a constant offset in the buffer which can only be removed by restart. If that happens again: Consider to change RAM writer to send zeros after reset to finish any open bursts.

• File upload is slow. Maybe ReadAsBinaryString is faster but fails with "out of memory" exception. Wait for Apply default memory limit in Mono env dotnet/aspnetcore#5617 to be solved.