I will write my theory about usrp working and some math in Am modulation, because I want to be sure before continuing:
If I want to modulate in DSB amplitude a carrier of saying 1GHz ,with a m(t) signal (in this case a simple 1kHz cosine tone) the carrier is sourcing by USRP module, and I have to set up the freq of usrp in 1GHz and based on Leon Couch Book the complex envelope for DSB AM should be I=Ac(1+m(t)) Q=0. (In my case Ac=1). This is equivalent to (1+m(t))(e^0) eq.1 I and Q are a complex signal that I connect to the usrp sink. Internally the usrp multiplies eq.1 by e^(2*pi*1GHz*t) resulting (1+m(t))e^(2*pi*1GHz*t) eq.2 Eq2. travels by the air to the receiver. In the USRP receiver, Eq. 2 is multiplied by e^-(2*pi*1GHz*t) resulting (1+m(t))(e^0) whose I and Q components are 1+m(t) and 0 respectively , and I can obtain the magnitude with a complex to magnitude block, this magnitude is 1+m(t). This my theory and I want to be sure if this is correct . Thanks.
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