Re: [Discuss-gnuradio] USRP2 and Data Rate

[Matt Ettus]

On 07/07/2010 08:32 AM, Garrett Wenger wrote:
> Hi all,
> A few days ago I made a simple program using grc to fsk modulate and
> transmit a pn sequence at 10kbps. Since I was using a USRP1, I set my
> samples per symbol to 25 and the interpolation to 512 to get this data
> rate.
>
> The place I work at just received a couple USRP2's, so I am trying to
> get this same program working with the new devices.  I realize that the
> DAC rate for the USRP2 is 100 MS/s instead of 128 MS/s, so I changed the
> samples per symbol and interpolation rate to  25 and 400, respectively,
> but this does not give me the 10kbps rate like I expected it would.
>
> Is there something major that I am missing here?


Your calculations appear correct, so I'm not sure why you aren't seeing 
10kbs.  What rate does it give you?

Also, 25 samples per symbol is a lot.  You would probably be better off 
doing an additional software decimate/interpolate by 5 operation (using 
an interpolating/decimating FIR filter) and using 5 samples per symbol.


Matt