UHD Error: recv packet demuxer unexpected sid

GNU Radio
1

Sometimes I run my python program I continuously get this error:
…
UHD Error:
recv packet demuxer unexpected sid 0x3fff9
UHD Error:
recv packet demuxer unexpected sid 0x4fff9
UHD Error:
recv packet demuxer unexpected sid 0xfffe0003
UHD Error:
recv packet demuxer unexpected sid 0xfffb0000
UHD Error:
recv packet demuxer unexpected sid 0x3
UHD Error:
recv packet demuxer unexpected sid 0x3fffc
…

Does anybody know where this error could come from?

My python program just writes some samples in a file, reconfigure the
central frequency and write again in a file with different name. Here is
the related code:

   for num in range(1,24):  #to iterate between 1 to 24
        tb.samp_rate = samp_rate = 2000000
        tb.fft_points = fft_points = 1024
        tb.frame_rate = frame_rate = int (samp_rate/fft_points/1000)
        center_freq = 914e6 + (num*2000000) # Center freq

modification
tb.set_center_freq(center_freq)
tb.disconnect((tb.logpwrfft_x_0, 0), (tb.blocks_file_sink_0,
0))
tb.blocks_file_sink_0 =
blocks.file_sink(gr.sizeof_float*fft_points, ‘/home//FILE_SINK/’+
‘914_+_’

  • str(num+num), False)
    tb.connect((tb.logpwrfft_x_0, 0), (tb.blocks_file_sink_0, 0))
    tb.start()
    while(tb.blocks_file_sink_0.nitems_read(0) <3): #3 arrays
    of
    1024
    pass
    tb.stop()
    tb.wait()
2

Hi Jorge,
if I’m not mistaken, this is still your B200, so this might be funky
stuff happening on USB3.
Important here is that you use the latest UHD; which version do you run
(first line of output of uhd_find_devices)?

Best regards,
Marcus

3

Hi Marcus,

Many thanks for your answer.
I got 3.8 version.

“linux; GNU C++ version 4.7.2; Boost_104900;
UHD_003.008.001-42-g8c87a524”

Then is it USB driver related?
Is it right the way I reconfigure my flowgrahp in order to change my
center
frequency ?
Thank you for your help.

Ragards,
Jorge.

4

Hi Jorge,

On 02/02/2015 08:21 AM, Jorge G. wrote:

Hi Marcus,

Many thanks for your answer.
I got 3.8 version.
“linux; GNU C++ version 4.7.2; Boost_104900; UHD_003.008.001-42-g8c87a524”
3.8.1 is quite recent; there’s only the 3.8.2 Release Candidate that you
could update to, so this is good.

Then is it USB driver related?
Possibly, but it often is.
Is it right the way I reconfigure my flowgrahp in order to change my
center frequency ?
I don’t think that has anything to do with the problem at hand.

Still: which sampling rate are you using? Can you try with a lower one?

Greetings,
Marcus

5

Hello Marcus,

I am using 10MS/s. The use of 5MS/s or 2MS/s
does not make any difference though.

If I just make a FFT of 20MS/s everything goes smoothly. I get errors
only
when reconfiguring the center frequency back and forth so I am
suspicious
that the sample rate is not the problem.

However I need those different center frequencies since I need to scan a
large BW. What is the best approach to do that?

Many thanks for you support.