On Tue, Dec 8, 2009 at 6:43 AM, Hanno Jung <[email protected]>wrote:
> Hi out there, > > I have several questions on Frequency Hopping. > > I'm trying to send a constant with the *_siggen.py files on different > frequencies in short intervalls. > Because those frequencies are spread over a band of 25MHz I need to change > the center frequency of the board very fast(within micro seconds). > > Now the question. > > Is the usrp1/2 capable of this via the functions in python? How much time > does the usrp need to change the center frequency? > > I have read a few articles abut the minimal available time interval on > desktop pcs. On ubuntu (hardy) there is a file called > /usr/src/linux-Headers-2.6.24-25/kernel/Kconfig.hz where I can adjust the > "Timer Interrupt Frequency Configuration" which allows 1000Hz which > represents 0.001 seconds. (important for python timer functions) > > Now the question. > Is this 0.001 s limit really the shortest time span available for this pc? > It seems to be too long. > Is there an other possibility to send ~8 carriers distributed over a > bandwitdh of 25MHz without preprocessed data? > Realtime/Frequency Hopping (tH=~several micro seconds) > I once looked in to this, and I believe that Matt once told me it takes ~200us for a daughterboard (I think it might have been RFX2400) to lock to a new frequency. You can always set your bandwidth to a larger range and then transmit at different offsets within that range. - George
_______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
