On Wed, Oct 3, 2012 at 2:00 AM, LD Zhang <[email protected]> wrote: > Hi Nick, > > Thanks for your helpful comments. I have followed up on this train of > thought on specifying a frequency for the USRP. I guess the advantage is one > can achieve the same level of over-sampling with lower sampling rate with > this technique when one shifts closer to the frequency of interest. I gave > it a try in the USRP and have the following observations: > > 1. The spectrum center essentially shifts to the specified frequency. No > band pass filtering seems to be applied at all. My only concern is that this > lack of band pass filtering may hinder dynamic range in certain cases but > not a problem for now.
Yes, that's right. The daughterboards are designed to have a wide range in frequency. If you are concerned about this issue, the idea is that you will have to provide your own filtering (and probably amplification) for a particular frequency band you are interested in. > 2. I have kind of a logistic question. I am running the GRC file which > directs the output to a file sink. Since I am doing different parameter > studies of the system performance, I need to generate different files with > different operating parameters. I don't know how to automatically dump > parameters like samp rate, samp duration, center freq, BW, gain, etc., to > the recorded file so that analysis can be somewhat automated. Maybe this is > a question that should be asked under a different subject heading. There is nothing that really does that right now. It's been on the to-do list for a while, but the issue is doing it right. There's a lot of history about how to store metadata in sample files, and we haven't wanted to lock ourselves into a way of doing this without using something that people would find the most useful. Tom > Thanks, > > LD _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
