Hi,

If the signal transmitted at the transmitter is represented as,

x(t) = X_i(t)cos(2*pi*fc*t) - X_q(t)sin(2*pi*fc*t), where X_i(t) and

X_q(t)

are inphase and quadrature components of the message signal.

then, at the receiver does the following equation correctly represent

the

signal after downcoversion to baseband like in a "RFX2400 + USRP’ set

up.

inphase component of received signal = X_i(t)cos(2*pi*f_offset*t + phi )
+
noise_component
quadrature component of received signal = X_q(t)sin(2*pi

*f_offset*t +

phi) +

noise_component

where, ‘f_offset’ is the frequency offset present and ‘phi’ is the

received

signal phase.

Can someone suggest a good reference to direct conversion receivers?

Thanks.