Re: [Discuss-gnuradio] saturation with multi_fft.py

[Tarun Tiwari]

Hi,
Thanks everybody, this thread helped me a lot to understand the multi antenna cabability of gnuradio.
I tried to run the multi_scope.py on a cingle USRP having two rfx2400 daughterboards with following changes in current multi_scope.py:

1) On line 44: nchan changed to 2 from 4
2) On Line 67: "len(self.subdev) != 4)"  changed to "len(self.subdev) != 2)"
3) On line 68 and 69: usrp_dbid.BASIC_RX changed to usrp_dbid.FLEX_2400_RX_MIMO_B

I generate sinusoid of 2.43G on a different machine/gnuradio and then run the command ./multi_scope.py -f2.43G -d128 -g0 on another machine with above changes, but i dont see anything other than noise on my scope. I tried different rbf files std_2rxhb_2tx.rbf, multi_2rxhb_2tx.rbf and got nothing, but the noise.

Next I changed the fpga_filename to multi_4rx_0tx.rbf, but i got following error:
Can't find fpga bitstream: multi_4rx_0tx.rbf
and program stoped with runtime error of "Can't open USRP"

Any suggestion?

Regards,
Tarun Mani Tiwari
MSEE student,
Multimedia Comm Lab,
UT Dallas

On 10/11/07, Martin Dvh < address@hidden> wrote:

address@hidden wrote:
> I'm sure you are right about the gui taking the majority of the cycles,
> but it's the real-time feedback that makes gnuradio so attractive.
> Ideally one would beable to switch them on and off as needed during
> operation of the program, which it is my understanding will be possible
> with the implementation of mblocks.
>
> As things stand now, is there a "refresh rate" control that I can
> modify, so that the scope sinks use less cycles?
Yes, you can set the following parameters.
sink    param           default         less cycles     Function
oscope  frame_decim     1               >1              keep one block in every "frame_decim"
fft     fft_rate        15.0            <15.0           refresh rate of fft_display

so for less GUI cycles set frame_decim to 10 or even 100
set fft_rate to 5.0 or even 1.0

I wished that fft_rate was set to 5.0 default because allmost allways 15.0 is too much a load on my machines.

Greetings,
Martin


> thanks,
> eric
>
> On Wed, 10 Oct 2007, Eric Blossom wrote:
>
>> On Wed, Oct 10, 2007 at 06:07:04PM -0400, address@hidden wrote:
>>> Ok, that works in principle, but I'm finding that I cannot sustain the
>>> same data rate as before on a fast dual core machine.
>>>
>>> I'm acquiring all 4 channels, and I'm doing both low-pass and high-pass
>>> filtering on all of them.  I am also displaying 5 sinks
>>> simultaneously; 1
>>> fft and 4 scopes.
>>
>> You'll most likely find that the bulk of your cycles are spent in the
>> gui.  Try disabling it.
>>
>>> So, in the long term it would help to have this sorted out in the
>>> fpga if
>>> that's possible; is that impossible as things stand now, or is there
>>> sufficient space in the 4rx no hb fpga?
>>
>> IIRC, the std_4rx_0tx.rbf configuration uses about 86% of the FPGA.
>>
>> Eric
>>
>
>
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