Forum: GNU Radio Sending a Sinusoidal Signal

Announcement (2017-05-07): www.ruby-forum.com is now read-only since I unfortunately do not have the time to support and maintain the forum any more. Please see rubyonrails.org/community and ruby-lang.org/en/community for other Rails- und Ruby-related community platforms.
Dbek B. (Guest)
on 2009-03-16 12:56
(Received via mailing list)
Hello,

i am currently working on the USRP2 board with the LFRX and LFTX
daughterboards. My big goal is to send and receive a signal with FM
transmission (I am using RFX2400 boards for that). But for now I just
want
to transmit a sinusoidal signal over a cable from LFRX to LFTX.

http://www.nabble.com/file/p22535722/loop_test2.grc.jpg



I am using the middle filter to use float signal but that is not a must.

I am ready to change everything such that I just can get the sinusoidal
signal on Scope Sink at the receiver. Please help me!

Thank you
--
View this message in context:
http://www.nabble.com/Sending-a-Sinusoidal-Signal-...
Sent from the GnuRadio mailing list archive at Nabble.com.
Dbek B. (Guest)
on 2009-03-16 12:59
(Received via mailing list)
To give more detail,

even in the following simple configuration i cannot receive the exact
signal
I am sending. I am very new to USRP2 and SDR.

My simplified system:

http://www.nabble.com/file/p22535780/loop_test.grc.jpg

My TX graph:

http://www.nabble.com/file/p22535780/graphTx.jpg

and finally what I receive:

http://www.nabble.com/file/p22535780/graphRX.jpg
--
View this message in context:
http://www.nabble.com/Sending-a-Sinusoidal-Signal-...
Sent from the GnuRadio mailing list archive at Nabble.com.
Henry Hallam (Guest)
on 2009-03-16 13:31
(Received via mailing list)
Hi dbeken,
I'm very much a radio newbie and don't even have a USRP yet, so take
this with a pinch of salt.
It looks like your signal is saturating the receiver, i.e. the output
power is too high.  Try putting an attenuator inline - maybe start
with 40dB or so?  Can you turn down the TX power and see if that
helps?

Good luck,

Henry
Dbek B. (Guest)
on 2009-03-16 13:42
(Received via mailing list)
Ok, i will try it. But here is another question. This looks like some
kind of
clipping as you said it, and from signal processing, I remember that
there
were some sort of Millican Terms (can be millian too, can`t figure out
right
now) with %9 overshoot at the edges of a rectangular signal (resulting
from
the addition of many sinusiodal signals). Well if that signal is coming
out
at my receiver, (and i am not sure of it too) what could be the reasons?

Thanks again



Henry Hallam-2 wrote:
>
>> I am sending. I am very new to USRP2 and SDR.
>>
>> removed_email_address@domain.invalid
>> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>
>
>
> _______________________________________________
> Discuss-gnuradio mailing list
> removed_email_address@domain.invalid
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>

--
View this message in context:
http://www.nabble.com/Sending-a-Sinusoidal-Signal-...
Sent from the GnuRadio mailing list archive at Nabble.com.
Dbek B. (Guest)
on 2009-03-16 14:11
(Received via mailing list)
I did set the amplitude in the signal source to 0.001. But still i don´t
get
a smooth output signal.

http://www.nabble.com/file/p22536861/saturation.jpg

What may be the problem in sampling rates, interpolations, decimations.

Thanks

Dincer



Henry Hallam-2 wrote:
>
>> I am sending. I am very new to USRP2 and SDR.
>>
>> removed_email_address@domain.invalid
>> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>
>
>
> _______________________________________________
> Discuss-gnuradio mailing list
> removed_email_address@domain.invalid
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>

--
View this message in context:
http://www.nabble.com/Sending-a-Sinusoidal-Signal-...
Sent from the GnuRadio mailing list archive at Nabble.com.
This topic is locked and can not be replied to.