Forum: GNU Radio LFRX problems

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C64c1417762c07a7587efc9af476f1bd?d=identicon&s=25 Brett L Trotter (Guest)
on 2006-05-04 21:59
(Received via mailing list)
I've been attempting to get my LFRX daughterboard working on a USRP
board. Most of the gnuradio-examples I've tried don't work on the LFRX
(they worked on basic rx). For instance, some of them come up and the
graph displays are not moving until I drop the gain to 0-3. Some lock up
and are not adjustable.

Is there something obvious I'm missing?

Is there a good frequency I should be able to pick up with am_rcv.py and
a 20ft piece of wire?
3719f4fea703e38bcbf8de6fe6bcdf55?d=identicon&s=25 Martin Dvh (Guest)
on 2006-05-05 01:04
(Received via mailing list)
Brett L Trotter wrote:
> I've been attempting to get my LFRX daughterboard working on a USRP
> board. Most of the gnuradio-examples I've tried don't work on the LFRX
> (they worked on basic rx). For instance, some of them come up and the
> graph displays are not moving until I drop the gain to 0-3. Some lock up
> and are not adjustable.
>
> Is there something obvious I'm missing?
The LFRX is a true DC - 30 Mhz board.
DC means you either have to apply the corrent DC-bias to your input

OR

AC-couple your inputs by using capacitors.

For my experiments with capturing analog baseband video with LFRX I used
ac-coupling for both ground and signal line.
(using several uFarad capacitors, to create a frequency response from 10
Hz to 30 MHz)

If you DC-connect the ground from LFRX to real ground without adding a
dc-bias directly you will probably get nothing out of it.

Greetings,
Martin
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