Re: [Discuss-gnuradio] Intermediate frequency question

[Nick Foster]

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 Wed, Oct 5, 2011 at 4:08 PM, Brook Lin <address@hidden> wrote:
>
> 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 Uher wrote:
>>
>>> 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
>>
>>
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>
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