On Mon, 2011-05-16 at 15:34 -0500, John Andrews wrote: > I am running it at 2.5GHz.
What magnitude are the samples you're feeding into the USRP sink? --n > > On Mon, May 16, 2011 at 12:39 PM, Nick Foster <[email protected]> wrote: > On Mon, 2011-05-16 at 12:32 -0500, John Andrews wrote: > > I am using the 1st generation USRP with RFX2400 > daughterboards each > > connected to the TX/RX interface. > > > > In the sine source block I am using a frequency of 100kHz. > As the > > interpolation of USRP sink is 128 I am using a sampling > frequency of > > 1Msps. > > > And what center frequency are you running at? > > --n > > > > > On Mon, May 16, 2011 at 12:27 PM, Nick Foster > <[email protected]> wrote: > > On Mon, 2011-05-16 at 12:23 -0500, John Andrews > wrote: > > > I am using GRC. I used a signal source block > generating a > > complex sine > > > at 100kHz. The USRP interpolation is 128 and the > sampling > > rate of the > > > sine generator is 1MHz. The USRP connected to > another > > computer has > > > USRP source configured at 64 decimation and is > connected to > > an FFT > > > block. I don't see any peak at the expected > frequency or > > anywhere in > > > the plot. Its just a flat plot. I checked the USRP > settings > > on both > > > and they are configured right. I even have > transmit gain and > > receive > > > gain as 10dB on both sides. > > > > > > What can be wrong here? > > > > > > What daughterboards are you using? What frequency > are you > > using on the > > source/sink blocks? The BasicRX/TX should be used > with >1MHz > > signals > > (configure the USRP source/sink center freq to 1MHz > or above), > > since the > > transformers won't pass lower frequencies than this. > > > > --n > > > > > > > > > > Thanks > > > > > > On Mon, May 16, 2011 at 12:09 PM, Marcus D. Leech > > <[email protected]> > > > wrote: > > > On 16/05/2011 1:03 PM, John Andrews wrote: > > > > Shouldn't I use some kind of modulation > scheme to > > do this, > > > > like FM or AM, to transmit a tone? > > > No, you can just transmit a narrow, > single-frequency > > tone, and > > > use the receivers FFT to determine how far > off it is > > from > > > where you expect it. > > > > > > use a signal-source producing a SIN wave > at, let's > > say, 1KHz, > > > feed that into a UHD/USRPx sink tuned to > whatever > > your > > > frequency is. > > > The tone will appear at TUNED-FREQUENCY > +1KHz. > > > > > > > > > > > > > > > > > > > > On Mon, May 16, 2011 at 10:02 AM, Marcus > D. Leech > > > > <[email protected]> wrote: > > > > On 16/05/2011 10:26 AM, > Alexander Chemeris > > wrote: > > > > You may also look into > this code: > > > > > http://thre.at/kalibrate/ > > > > It estimates offset of > an USRP > > with regards > > > > to a GSM base station, > but > > > > it can be easily > modified to > > measure offset > > > > from any clean tone, > e.g. > > > > transmitted by a second > USRP. > > > > > > > > Keep in mind that the offset > measured must > > > > necessarily be the total > offset--that is, > > both Rx > > > > and Tx can be "off" in > frequency. > > > > > > > > The practical consequence should > be NIL, > > because > > > > frequency correction should > normally only > > be done on > > > > the Rx-side, and it should > > > > simply adapt to whatever it > sees, > > regardless of the > > > > Tx and Rx components of the > offset. > > > > > > > > > > > > > > _______________________________________________ > > > > Discuss-gnuradio mailing list > > > > [email protected] > > > > > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > > > > > > > > > > > _______________________________________________ > > > Discuss-gnuradio mailing list > > > [email protected] > > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > > > > > > > _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
