[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] Recovering x(t) from IQ samples
From: |
Jens Elsner |
Subject: |
Re: [Discuss-gnuradio] Recovering x(t) from IQ samples |
Date: |
Sat, 18 Aug 2007 15:00:39 +0200 |
User-agent: |
Mutt/1.5.9i |
> So the problem remains: Given only the i(t) and q(t) samples, which is all
> the USRP gives back, how do I reconstruct x(t)?
Two options:
1) you need some kind of phase reference (coherent
demodulation), insert pilot symbols into x(t)
2) use AM modulation over one carrier only; this requires x(t) to have a
known maximum amplitude:
Let's assume x(t) in [-1, 1] and zero mean.
The carrier c(t) = c_0 cos(wt+phi) is used to modulate x(t):
s(t) = ( c_0 + x(t) ) cos(wt+phi) .
This requires c_0 to be greater than 1, otherwise the sign
ambiguity you've been talking about occurs.
Please correct me if I'm mistaken. All in all it would be best to know
what this BBC application is supposed to do.
Regards,
Jens
- [Discuss-gnuradio] Recovering x(t) from IQ samples, Bahn William L Civ USAFA/DFCS, 2007/08/16
- RE: [Discuss-gnuradio] Recovering x(t) from IQ samples, Bahn William L Civ USAFA/DFCS, 2007/08/16
- Re: [Discuss-gnuradio] Recovering x(t) from IQ samples, Johnathan Corgan, 2007/08/17
- RE: [Discuss-gnuradio] Recovering x(t) from IQ samples, Bahn William L Civ USAFA/DFCS, 2007/08/17
- Re: [Discuss-gnuradio] Recovering x(t) from IQ samples, Jens Elsner, 2007/08/18
- Re: [Discuss-gnuradio] Recovering x(t) from IQ samples, Jonathan P Jacky, 2007/08/18
- Re: [Discuss-gnuradio] Recovering x(t) from IQ samples, Jeff Brower, 2007/08/18
- Re: [Discuss-gnuradio] Recovering x(t) from IQ samples, Jonathan Jacky, 2007/08/20
- Re: [Discuss-gnuradio] Recovering x(t) from IQ samples, Chris Stankevitz, 2007/08/20
- Re: [Discuss-gnuradio] Recovering x(t) from IQ samples, Brian Padalino, 2007/08/20
- Re: [Discuss-gnuradio] Recovering x(t) from IQ samples,
Jens Elsner <=
- [Discuss-gnuradio] Problem with the FPGA firmware (getting clock like output only), eenrti, 2007/08/19
Re: [Discuss-gnuradio] Recovering x(t) from IQ samples, Jeff Brower, 2007/08/17