(1) I mean “usrp.tune”, use the instruction i can set my target
frequency at 13.56MHz.
Now, I know you mean Usrp output I/Q samples. And you want to use one of
them (I or Q sample).
My answer is NO, because I/Q sample you can see it like SIN and COS
signal. So need both I/Q to demodulate signal. (If I am wrong, please
The detail in book is very diffcult to me. I don’t know how to explain.
Maybe someone can help me to explain it.
Sorry for my misunderstand before.
Use fft_sink, you can see usrp get the target frequency signal.
for example, my target is 13.56MHz. When my RFID device near USRP, I
will see a wavefrom raise in 13.56MHz.
(3) In ISO/IEC 14443A
PCD to PICC using ASK100%, PICC to PCD using different modulation (OOK).
I just got draft spec. I need more study to understand the spec.
(4) My question to RFID spec. Do you know, what is Pause_A?
Marco Bottino wrote:
What do you mean with tune the target frequency? Isn’t the carrier
However, I don’t understand the question “why USRP outputs I/Q samples?”
I have to reading more knowledge about communication theory.
I asked that because in my opinion I should not need any kind of phase
information because of the ASK modulation used that is an amplitude
So I don’t know if I have simply to throw away the Q samples or not…
(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.
I’m sorry for my ignorance but which is the information carried by the
With “demodulation” what do you exactly mean? USRP isn’t able to sample
directly at the RFID’s frequency?
Finally, reading the ISO standards it seems that is always used the ASK
modulation… isn’t it?