Dear all,
I am getting started with the USRP2 blocks from Matlab 2010b along with the USRP2 and the XCVR2450 transceiver.

After running Simulink demos I have several questions about the receiver part:

1) If I set a decimation less than 512 the 'Lost packets' output reports a lot of dropped packages. Since I have a quite new quad-core laptop I think it should be enough to run this setup. Do I have to set-up some optimum configuration parameters elsewhere in order not to loose packets? By the way, how is the lost packet output triggered? I mean how the block figures out that more data arrived to the UDP buffer and it couldn't be stored. I would like to know the inside of the block (besides the USRP2_RX code that doesn't say a lot).

If I close the FFT scope form the demo the number of lost packets decreases. Could only the commusrp2 demo take all my CPU capability? I expected to see it running with different decimation values and the spectrum scope at the same time.

2) is it possible to change the length of the output USRP2 vector? I can see it is 358x1 but I don't find the option to change it. (frameLength)

I would like to talk about this issues from some knowledged person.

Many thanks in advance,
Jorge.

i have the same problems...

"Jorge " <jmiggal@gmail.com> wrote in message <iamnov$iuo$1@fred.mathworks.com>...
> Dear all,
> I am getting started with the USRP2 blocks from Matlab 2010b along with the USRP2 and the XCVR2450 transceiver.
> 
> After running Simulink demos I have several questions about the receiver part:
> 
> 1) If I set a decimation less than 512 the 'Lost packets' output reports a lot of dropped packages. Since I have a quite new quad-core laptop I think it should be enough to run this setup. Do I have to set-up some optimum configuration parameters elsewhere in order not to loose packets? By the way, how is the lost packet output triggered? I mean how the block figures out that more data arrived to the UDP buffer and it couldn't be stored. I would like to know the inside of the block (besides the USRP2_RX code that doesn't say a lot).
> 
> If I close the FFT scope form the demo the number of lost packets decreases. Could only the commusrp2 demo take all my CPU capability? I expected to see it running with different decimation values and the spectrum scope at the same time.
> 
> 2) is it possible to change the length of the output USRP2 vector? I can see it is 358x1 but I don't find the option to change it. (frameLength)
> 
> I would like to talk about this issues from some knowledged person.
> 
> Many thanks in advance,
> Jorge.

but i put the cf to 2.35e9 hz ,it works ,through there are lots of packets losts.but the received spectrum seems well.

hi 
Jorge i am also running commusrp2_tx.mdl  and commusrp2.mdl but there is big difference in the transmitted and received signal and it shows lots of packet LOSS
i have changed the center frequency many times and gain and decimation as well 
but still the shape of the signal is very bad and lost of packet loss please tell me that 
what can be possible reason behind it.i will obliged to you.

regards 
YASIR ATEEQ



"Jorge " <jmiggal@gmail.com> wrote in message <iamnov$iuo$1@fred.mathworks.com>...
> Dear all,
> I am getting started with the USRP2 blocks from Matlab 2010b along with the USRP2 and the XCVR2450 transceiver.
> 
> After running Simulink demos I have several questions about the receiver part:
> 
> 1) If I set a decimation less than 512 the 'Lost packets' output reports a lot of dropped packages. Since I have a quite new quad-core laptop I think it should be enough to run this setup. Do I have to set-up some optimum configuration parameters elsewhere in order not to loose packets? By the way, how is the lost packet output triggered? I mean how the block figures out that more data arrived to the UDP buffer and it couldn't be stored. I would like to know the inside of the block (besides the USRP2_RX code that doesn't say a lot).
> 
> If I close the FFT scope form the demo the number of lost packets decreases. Could only the commusrp2 demo take all my CPU capability? I expected to see it running with different decimation values and the spectrum scope at the same time.
> 
> 2) is it possible to change the length of the output USRP2 vector? I can see it is 358x1 but I don't find the option to change it. (frameLength)
> 
> I would like to talk about this issues from some knowledged person.
> 
> Many thanks in advance,
> Jorge.