Hi, If I am using RFX2400 then what is the IF frequency and can we change this to some other value? Correct me if the question I asked is wrong. Thanks, Ali
on 2009-05-13 06:06
on 2009-05-13 09:22
> If I am using RFX2400 then what is the IF frequency and can we change this > to some other value? Correct me if the question I asked is wrong. With the RFX2400, and most of the high frequency usrp daughtercards, there is no IF frequency. The samples you receive (or send) from the usrp.source_x (or usrp.sink_x) are baseband I and Q values. Jason
on 2009-05-13 10:26
Yeah, I got it. I read in a tutorial and I understand now. Thanks again.
on 2009-05-14 10:28
Mir A.-4 wrote: > > Yeah, I got it. I read in a tutorial and I understand now. > > > hi Ali, what tutorial do you read for this? hope it will be useful to others especially to me =) tQ Adib -- View this message in context: http://www.nabble.com/Intermediate-frequency-quest... Sent from the GnuRadio mailing list archive at Nabble.com.
on 2011-10-06 03:08
Hi All, I am confused on this reply. The reply said that "With the RFX2400, and most of the high frequency usrp daughtercards, there is no IF frequency". How is that possible? For RFX2400 the RF range is from 2.3GHz to 2.9GHz, the ADC rate for USRP1 is 64MS/s. If there is no IF frequency, the ADC rate is obviously too low. There must be RF front-end on the daughterboard to tune the RF to the IF. Right? If so, my question is what the IF is? Obviously, f_IF = f_RF - f_LO. (1) Are we setting the f_LO when we tune the usrp by usrp.tune(self.u, 0, self.subdev, target_freq)? (2) How to figure out f_IF for different daughterboards? Thanks in advance, Brook Jason U. wrote: > > > _______________________________________________ > Discuss-gnuradio mailing list > firstname.lastname@example.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- View this message in context: http://old.nabble.com/Intermediate-frequency-quest... Sent from the GnuRadio mailing list archive at Nabble.com.
on 2011-10-06 03:12
By "no IF frequency" he meant the LO frequency is the same as the RF frequency. This is called a zero-IF receiver, or direct conversion. http://en.wikipedia.org/wiki/Direct-conversion_receiver --n
on 2011-10-06 03:46
On 10/05/2011 07:11 PM, Nick F. wrote: > By "no IF frequency" he meant the LO frequency is the same as the RF > frequency. This is called a zero-IF receiver, or direct conversion. > > http://en.wikipedia.org/wiki/Direct-conversion_receiver > > --n > More precisely, and completely, they use a direct-conversion, quadrature (I + Q) signal format. Without the I+Q bits, then the the two side-bands created from mixing the RF with LO==RF would cause them to "fold about each other". In the very, very, early days of direct-conversion designs (way back near the start of the 20th century), the fact that the two side-bands overlapped wasn't an issue, because the modulation mode was typically AM, which "doesn't care" about such things. But for anything else, you need to use a complex representation, in order to distinguish (-bandwidth/2-DC) from (DC-bandwidth/2). -- Marcus L. Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org