Forum: GNU Radio Problem setting USRP transmitting signal power

Hi~

I found some strange problem setting USRP transmitting signal power. The
method I change the transmit power is to use a constant to multiply the
signals. the problem is that I use bigger constant like 2.0, the SNR 
value i
calculate is lower than using constant like 1.0. the transmit signal 
values
are 0.005,-0.005. my experiment platform is USRP N210 plus motherboard
RFX2400. Is there anything wrong or there are better method to setting 
USRP
transmiting power?

thanks!!!



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On Sun, Feb 24, 2013 at 10:36 PM, warren4300137 
<warren4300137@gmail.com> wrote:
> thanks!!!
The USRPs take in normalized signals, so you want to scale your
signals to +/-1 at most. If you want increased power, adjust the gain
of the USRP itself.

The reason you're seeing a bad signal as you increase the amplitude is
that you are causing nonlinearities in the hardware from a signal
that's too large. So even though the USRP will take in a +1 signal,
you'll want to back off some to keep the signal in the linear range of
the transmitter.

Tom