[Discuss-gnuradio] Re: Complex samples format with ASK modulation

[C.cc Jay]

Hello Marco

I not familiar with RFID ASK10% or ASK100%.

(1)
I use usrp -> sinkfft. I can see the wave and tune the target frequency 
to 13.56MHz

However, I don't understand the question "why USRP outputs I/Q samples?"
I have to reading more knowledge about communication theory.

(2) You want to plot in the time domain
When I got RFID signal, I will do demodulation and get the information 
carried by the phase. I still trying.

CJay

Marco Bottino wrote:
> hello everybody,
> 
> I am using the USRP with LFRX daughterboard to catch an RFID signal ASK
> modulated (frequency 13.56MHz, decimation factor 16).
> I really need an help because I don't understand very well the meaning 
> of the
> outputs of my USRP: if the information related to the ASK is only the
> amplitude, so  why USRP outputs I/Q samples?
> Which is the meaning of the Q samples? Which is the information carried 
> by the
> phase (that should not be important in ASK modulation)?
> If I want to plot in the time domain the samples got, which kind of 
> operation is
> necessary (given that I would compare my result with the 
> usrp_oscope.py)?
> 
> Any kind of help will be really well appreciated.
> Thank you,
> 
> Marco

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